Structural Determinants Research Articles

Social and Structural Determinants of Health Associated with COVID-19 Vaccine Hesitancy among Older Adults in the United States

State-level COVID-19 vaccination rates among older adults have been uneven in the United States. Due to the immunocompromised nature of older adults, vaccine hesitancy increases the risk of morbidity and mortality. This study aims to determine the association between the social determinants of health, the structural determinants of health, and COVID-19 vaccine hesitancy among older adults in the United States. Secondary data from the Health and Retirement Study (HRS) dataset were used. A descriptive analysis and multinomial multivariable logistic regression were performed to examine the association of the independent variables—gender, age, race, immigration status, marital status, broadband internet access, social security income, Medicare coverage, education, and frequency of religious service—with the dependent variable, vaccine hesitancy. Compared to the respondents with no vaccine hesitancy and without the specific predictor, the respondents who reported religious attendance at least once/week were more likely to be “somewhat hesitant”, divorced respondents had higher odds of being “somewhat hesitant”, and older adults aged 65–74 years were more likely to be “very hesitant” or “somewhat hesitant” about the COVID-19 vaccine. Compared to the respondents with no vaccine hesitancy and without the specific predictor, females had higher odds of being “very hesitant”, “somewhat hesitant”, or a “little hesitant”, and African Americans were more likely to be “very hesitant”, “somewhat hesitant”, or a “little hesitant” about the COVID-19 vaccine. Addressing these factors may limit the barriers to vaccine uptake reported among older adults and improve herd immunity among the immunocompromised population.

'You never know when you will need an antibiotic': A qualitative study of structural barriers and cultural assumptions in antibiotic misuse among immigrants in the United States.

The use of nonprescribed antibiotics increases the risk of antibiotic resistance, which is a primary public health concern of the 21st century. This study explores structural and cultural determinants of antibiotic misuse among immigrants living in the United States who arrived from home countries with easier access to antibiotics. Adopting a qualitative approach, we interviewed 34 immigrants living in the United States and who had traveled back to their home countries within 1year of the interview. We followed the steps of constructive grounded theory to analyze the data. We found two primary influences of immigrants' use of nonprescribed antibiotics. The first was structural barriers to health care access in the host country, including insurance coverage, cost of an emergency department visit, cost of missing a paid day of work, complexity of the healthcare system, and communication issues with health care providers. The second was participants' cultural assumptions, including their experiences of antibiotics use, beliefs about antibiotics, a habit of self-medication, and uncertainty about future medical needs. This study informs policymakers concerned with combating antibiotic resistance. Promoting antibiotic stewardship among immigrants from countries with lax antibiotic-prescribing practices and improving access to appropriate channels for preventative and same-day care may reduce the inappropriate use of antibiotics.

The structural landscape and diversity of Pyricularia oryzae MAX effectors revisited.

Magnaporthe AVRs and ToxB-like (MAX) effectors constitute a family of secreted virulence proteins in the fungus Pyricularia oryzae (syn. Magnaporthe oryzae), which causes blast disease on numerous cereals and grasses. In spite of high sequence divergence, MAX effectors share a common fold characterized by a ß-sandwich core stabilized by a conserved disulfide bond. In this study, we investigated the structural landscape and diversity within the MAX effector repertoire of P. oryzae. Combining experimental protein structure determination and in silico structure modeling we validated the presence of the conserved MAX effector core domain in 77 out of 94 groups of orthologs (OG) identified in a previous population genomic study. Four novel MAX effector structures determined by NMR were in remarkably good agreement with AlphaFold2 (AF2) predictions. Based on the comparison of the AF2-generated 3D models we propose a classification of the MAX effectors superfamily in 20 structural groups that vary in the canonical MAX fold, disulfide bond patterns, and additional secondary structures in N- and C-terminal extensions. About one-third of the MAX family members remain singletons, without strong structural relationship to other MAX effectors. Analysis of the surface properties of the AF2 MAX models also highlights the high variability within the MAX family at the structural level, potentially reflecting the wide diversity of their virulence functions and host targets.

Determinants of public-private partnership governance structures: evidence from India

ABSTRACT Public-private partnerships (PPPs) represent a continuum of governance structures characterized by wide variability in private sector risk transfer. Despite the widespread adoption of PPPs, few studies examine the reasons for such heterogeneity. We investigate the factors explaining variability across PPP governance structures and their impact on the extent of private sector risk transfer using ordinal logistic regression on a novel dataset of 2330 Indian PPP projects. We find that the risk transfer is mainly driven by economic and fiscal factors, service-specific transaction costs and project-specific factors, while political factors and institutional quality barely influence it.

Patient Experience and Nurse Staffing Level in South Korea.

Patient experience has recently become a key driver for hospital quality improvement in South Korea, marked by the introduction of the Patient Experience Assessment (PXA) within its National Health Insurance (NHI) in 2017. While the PXA has garnered special attention from the media and hospitals, there has been a lack of focus on its structural determinants, hindering continuous and sustained improvement in patient experience. Given the relatively low number of practicing nurses per 1,000 population in South Korea and the significant variation in nurse staffing levels across hospitals, the staffing level of nurses in hospitals could be a crucial structural determinant of patient experience. This study examines the association between patient experience and hospital nurse staffing levels in South Korea. We used individual- and hospital-level data from the 2019 PXA, encompassing 7,250 patients from 42 tertiary hospitals and 16,235 patients from 109 non-tertiary general hospitals with 300 or more beds. The dependent variables were derived from the complete set of 21 proper questions on patient experience in the Nurse and other domains. The main explanatory variable was the hospital-level Nurse Staffing Grade (NSG), employed by the NHI to adjust reimbursement to hospitals. Multi-level ordered/binomial logistic or linear regression was conducted accounting for other hospital- and patient-level characteristics as well as acknowledging the nested nature of the data. A clear, positive association was observed between patient experience in the Nurse domain and NSG, even after accounting for other characteristics. For example, the predicted probability of reporting the top-box category of "Always" to the question "How often did nurses treat you with courtesy and respect?" was 70.3% among patients from non-tertiary general hospitals with the highest NSG, compared to 63.1% among patients from their peer hospitals with the lowest NSG. Patient experience measured in other domains that were likely to be affected by nurse staffing levels also showed similar associations, although generally weaker and less consistent than in the Nurse domain. Better patient experience was associated with higher hospital nurse staffing levels in South Korea. Alongside current initiatives focused on measuring and publicly reporting patient experience, strengthening nursing and other hospital workforce should also be included in policy efforts to improve patient experience.

Comprehensive clinical and genetic analyses of circulating bile acids and their associations with diabetes and its indices.

Bile acids (BAs) are cholesterol-derived compounds that regulate glucose, lipid, and energy metabolism. Despite their significance in glucose homeostasis, the association between specific BA molecular species and their synthetic pathways with diabetes mellitus (DM) is unclear. Here, we used a recently validated stable-isotope dilution highperformance liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify a panel of BAs in fasting plasma from subjects (n=2,145) and explored structural and genetic determinants of BAs linked to DM, insulin resistance and obesity. Multiple 12α-hydroxylated BAs were associated with DM [adjusted odds ratios (aORs):1.3-1.9 (all P<0.05)] and insulin resistance [aORs:1.3-2.2 (all P<0.05)]. Conversely, multiple 6a-hydroxylated BAs and isolithocholic acid (Iso-LCA) were inversely associated with DM and obesity [aORs:0.3-0.9 (all P<0.05)]. Genome-wide association studies (GWAS) revealed multiple genome-wide significant loci linked with nine of the 14 DM-associated BAs, including a locus for Iso-LCA (rs11866815). Mendelian randomization analyses showed genetically elevated DCA levels were causally associated with higher BMI, and Iso-LCA levels were causally associated with reduced BMI and DM risk. In conclusion, comprehensive large-scale quantitative mass spectrometry and genetics analyses show circulating levels of multiple structurally specific BAs, especially DCA and Iso-LCA, are clinically associated with and genetically linked to obesity and DM.

Family Management and Historical Origins: The Italian Experience

ABSTRACTResearch Question/IssueThe purpose of this paper is to analyze the long‐run determinants of the corporate structure of Italian firms to explain the persistent role of a long‐run tradition of civic capital that has favored interpersonal trust, fostered cooperation outside of the narrow ties of family members and limited the diffusion of family businesses managed predominantly by family members.Research Findings/InsightsWe examined a large sample of Italian listed and not listed firms and identified those that operate in current municipalities that in the past used to be independent communes. Such firms featuring experiences of civic engagement are today less likely to be owned by a family and run by family management.Theoretical/Academic ImplicationsOur findings highlight the role of institutions as drivers of corporate governance and signal that long forgotten institutions, by modifying local social capital, may interact with family social capital and have important persistent effects on current corporate governance arrangements. Therefore, significant elements of path dependency may explain current patterns of unbundling of ownership and management.Practitioner/Policy ImplicationsPersistent corporate governance structures are difficult even for policymakers to modify. Our findings suggest that political measures should favor the accumulation of social capital at the local level when aiming to change ownership and management arrangements and limit the misallocation of resources due to family management.

Abstract PO5-20-05: The FOR ME (Fostering Opportunities in Research through Messaging and Education) study: Using multiple qualitative methods to develop a culturally sensitive narrative intervention to promote equity in clinical trials

Abstract Background: Black women are more likely to present with advanced stage disease and to die following a breast cancer (BC) diagnosis compared to women from other racial/ethnic groups. In 2020, only 7.2% of enrollees in clinical trials that led to the approval of 3 novel drugs for breast cancer were Black. While there are many contributing factors to this inequity (i.e., tumor biology, social and structural health determinants, racial injustice, and differential access to and utilization of high-quality mammography, diagnostics, and therapies), persistent underrepresentation of Black patients in cancer clinical trials (CTs) slows scientific advancements. Objective: The aim of this study is to develop, optimize, and test a narrative decision aid intervention (web-based video) for Black women diagnosed with BC to promote shared decision making and CT participation. The first aim is to conduct multiple qualitative methods with multi-level stakeholders to identify barriers, facilitators, and intervention priorities that would assist Black breast cancer patients to make informed decisions about participating in clinical trials. The second aim is to create a culturally sensitive, narrative intervention designed to support decision making and motivate Black breast cancer patients to participate in clinical trials. Aim 3 will then pilot a study to determine acceptability of the intervention among patients and assess whether it increases clinical trial participation in a safety net oncology practice. Methods: Guided by community-based participatory research approaches, we used multiple qualitative methods (key informant interviews (KIIs) and story circles) to identify barriers and facilitators that support decision-making and CT participation. The KIIs, completed in-person, via phone, or video conferencing, were recorded and professionally transcribed. The research team used thematic analysis and inductive coding approaches. Next, interviews and focus groups will invite feedback on the educational/motivational content of the intervention and will be used to develop a culturally sensitive script and story boards. A video production company will produce the narrative intervention. Finally, focus groups and interviews with participant cohorts will provide feedback on the completed intervention. Black women diagnosed with BC will view the intervention in an oncology clinic. Using a pretest/posttest design, we will analyze the acceptability of the intervention and its effect on intention to participate in clinical trials. We will then conduct a quasi-experimental study in a safety net oncology practice to determine whether the rate of clinical trial participation among Black breast cancer patients increases following implementation of the intervention as a standard component of new patient education. Progress: Recruitment started in July 2022 and currently 30 of 30 interviews with patients are completed, 20 of 20 interviews with clinical stakeholders (oncologists and clinical trial staff) are completed, and 14 of 20 interviews with advocates and community partners are completed. Data collection and the analysis of the interviews and story circles is ongoing. Citation Format: Neha Hippalgaonkar, Ryan Nguyen, Leslie Carnahan, Vida Henderson, Tigist Mersha, Eliza Cohn, Kauthar Salum, Ana Williams, Lolita Coleman, Beulah Brent, AnneMarie Murphy, Paris Thomas, Paramjeet Khosla, Kent Hoskins. The FOR ME (Fostering Opportunities in Research through Messaging and Education) study: Using multiple qualitative methods to develop a culturally sensitive narrative intervention to promote equity in clinical trials [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-20-05.

Structural determinants for activity of the antidepressant vortioxetine at human and rodent 5-HT3 receptors.

Vortioxetine (VTX) is a recently approved antidepressant that targets a variety of serotonin receptors. Here, we investigate the drug's molecular mechanism of operation at the serotonin 5-HT3 receptor (5-HT3R), which features two properties: VTX acts differently on rodent and human 5-HT3R, and VTX appears to suppress any subsequent response to agonists. Using a combination of cryo-EM, electrophysiology, voltage-clamp fluorometry and molecular dynamics, we show that VTX stabilizes a resting inhibited state of the mouse 5-HT3R and an agonist-bound-like state of human 5-HT3R, in line with the functional profile of the drug. We report four human 5-HT3R structures and show that the human receptor transmembrane domain is intrinsically fragile. We also explain the lack of recovery after VTX administration via a membrane partition mechanism.

Social and Structural Determinants of Cardiovascular Complications of Diabetes.

Cardiovascular disease (CVD) is the leading cause of mortality in people who have diabetes. Racial and ethnic minorities with diabetes have suboptimal management of cardiovascular risk factors, leading to higher mortality. Social and structural determinants of health are external factors that influence an individual's ability to choose positive health behaviors. In this review, we will discuss cardiovascular complications in people who have diabetes and their relationship to social determinants of health (SDOH). Recent innovations in diabetes treatment, including new devices and medications, have improved care and survival. However, disparities in the availability of these treatments to racial and ethnic minorities may contribute to continued inequities in CVD outcomes. Racial/ethnic disparities in CVD relate to inequities in economic opportunity, education and health literacy, neighborhoods and social cohesion, and health care access and quality driven by structural racism.

Exploring Binding Pockets in the Conformational States of the SARS-CoV-2 Spike Trimers for the Screening of Allosteric Inhibitors Using Molecular Simulations and Ensemble-Based Ligand Docking.

Understanding mechanisms of allosteric regulation remains elusive for the SARS-CoV-2 spike protein, despite the increasing interest and effort in discovering allosteric inhibitors of the viral activity and interactions with the host receptor ACE2. The challenges of discovering allosteric modulators of the SARS-CoV-2 spike proteins are associated with the diversity of cryptic allosteric sites and complex molecular mechanisms that can be employed by allosteric ligands, including the alteration of the conformational equilibrium of spike protein and preferential stabilization of specific functional states. In the current study, we combine conformational dynamics analysis of distinct forms of the full-length spike protein trimers and machine-learning-based binding pocket detection with the ensemble-based ligand docking and binding free energy analysis to characterize the potential allosteric binding sites and determine structural and energetic determinants of allosteric inhibition for a series of experimentally validated allosteric molecules. The results demonstrate a good agreement between computational and experimental binding affinities, providing support to the predicted binding modes and suggesting key interactions formed by the allosteric ligands to elicit the experimentally observed inhibition. We establish structural and energetic determinants of allosteric binding for the experimentally known allosteric molecules, indicating a potential mechanism of allosteric modulation by targeting the hinges of the inter-protomer movements and blocking conformational changes between the closed and open spike trimer forms. The results of this study demonstrate that combining ensemble-based ligand docking with conformational states of spike protein and rigorous binding energy analysis enables robust characterization of the ligand binding modes, the identification of allosteric binding hotspots, and the prediction of binding affinities for validated allosteric modulators, which is consistent with the experimental data. This study suggested that the conformational adaptability of the protein allosteric sites and the diversity of ligand bound conformations are both in play to enable efficient targeting of allosteric binding sites and interfere with the conformational changes.

Disruption of Ca2+/calmodulin:KSR1 interaction lowers ERK activation.

KSR1, a key scaffold protein for the MAPK pathway, facilitates ERK activation upon growth factor stimulation. We recently demonstrated that KSR1 binds the Ca2+-binding protein calmodulin (CaM), thereby providing an intersection between KSR1-mediated and Ca2+ signaling. In this study, we set out to generate a KSR1 point mutant with reduced Ca2+/CaM binding in order to unravel the functional implications of their interaction. To do so, we solved the structural determinants of complex formation. Using purified fragments of KSR1, we showed that Ca2+/CaM binds to the CA3 domain of KSR1. We then used in silico molecular modeling to predict contact residues for binding. This approach identified two possible modes of interaction: (1) binding of extended Ca2+/CaM to a globular conformation of KSR1-CA3 via electrostatic interactions or (2) binding of collapsed Ca2+/CaM to α-helical KSR1-CA3 via hydrophobic interactions. Experimentally, site-directed mutagenesis of the predicted contact residues for the two binding models favored that where collapsed Ca2+/CaM binds to the α-helical conformation of KSR1-CA3. Importantly, replacing KSR1-Phe355 with Asp reduces Ca2+/CaM binding by 76%. The KSR1-F355D mutation also significantly impairs the ability of EGF to activate ERK, which reveals that Ca2+/CaM binding promotes KSR1-mediated MAPK signaling. This work, by uncovering structural insight into the binding of KSR1 to Ca2+/CaM, identifies a KSR1 single-point mutant as a bioreagent to selectively study the crosstalk between Ca2+ and KSR1-mediated signaling.

Antenatal care services in Yobe state Nigeria: The determinants and interventions to increase utilization

Introduction: Maternal and perinatal mortality are global public health issues and Nigeria in particular carries a high burden as 33,000 women dies every year though significant decline in maternal mortality ratio has been observed; neonatal mortality rate is 37 per 100,000 livebirths against the 2015 MDGs target of 12 per 100, 000 and stillbirth is unbearably high. Yobe State remains one of the regions with high maternal and perinatal death in Nigeria most of which are preventable with quality Antenatal care (ANC) services yet the ANC coverage is only 49% against the Nigerian national figure of 68.9% (which is moderate) and more than 67% of the pregnant women did not receive atleast 4 ANC visits in Yobe as recommended by World Health Organization. The aimed of this study was to analyse and recommend interventions in ANC services in order to increase utilization to improve maternal and perinatal health in Yobe State, Nigeria. Methods: This is an in-depth study on ANC service utilization from local and international literatures; databases used are PubMed, Medline and Global health. The conceptual framework is based on socio ecological model. The analytical tools used to analyse the proposed intervention strategies are based on the criteria of technical effectiveness, organisational feasibility, sociocultural feasibility, financial feasibility and equity consideration. Results: Multilevel determinants are responsible for low Utilization of ANC services in Yobe State which include intrapersonal (women education and literacy), interpersonal (families, peers, relatives influence), community (culture and beliefs), health system (health services, human resources, and health policy) and structural determinants (conflicts and poverty). Effective and feasible strategies to increase ANC services Utilization identified and appraised include outreach and health and education; men involvement in ANC; community based health insurance scheme; improving the skills and supportive supervision of ANC providers; employment of CHW and task shifting to lower cadres. Conclusion: ANC services requires multi-dimensional approach to increase Utilization, each intervention augment one another for the desired effects and better outcome of improving maternal and perinatal health. Further research is recommended on interventions of determinants like conflicts, poverty and women education which are beyond the scope of this dissertation and men involvement in ANC, community based health insurance scheme, improving the skills and supportive supervision of health ANC providers; task shifting to lower cadres and further research.

Secondary Sites of the C-type Lectin-Like Fold.

C-type lectins are a large superfamily of proteins involved in a multitude of biological processes. In particular, their involvement in immunity and homeostasis has rendered them attractive targets for diverse therapeutic interventions. They share a characteristic C-type lectin-like domain whose adaptability enables them to bind a broad spectrum of ligands beyond the originally defined canonical Ca2+-dependent carbohydrate binding. Together with variable domain architecture and high-level conformational plasticity, this enables C-type lectins to meet diverse functional demands. Secondary sites provide another layer of regulation and are often intricately linked to functional diversity. Located remote from the canonical primary binding site, secondary sites can accommodate ligands with other physicochemical properties and alter protein dynamics, thus enhancing selectivity and enabling fine-tuning of the biological response. In this review, we outline the structural determinants allowing C-type lectins to perform a large variety of tasks and to accommodate the ligands associated with it. Using the six well-characterized Ca2+-dependent and Ca2+-independent C-type lectin receptors DC-SIGN, langerin, MGL, dectin-1, CLEC-2 and NKG2D as examples, we focus on the characteristics of non-canonical interactions and secondary sites and their potential use in drug discovery endeavors.

Perceived legal protection and institutional trust predict a lower psychological distress level for transgender people in Aotearoa/New Zealand

Background Few studies have assessed the role of legal protection and institutional trust as structural determinants of health among trans people. Aim This study investigated the responses of a nationwide survey of trans people in Aotearoa New Zealand to examine the interplay among perceived legal protection, trust toward institutions, and psychological distress. Method Data were employed from the 2018 Counting Ourselves survey (n = 863; Mage = 30.3). We conducted chi-square analyses to identify the extent of differences for institutional trust between trans participants and the Aotearoa/New Zealand general populations. Correlation and mediation analyses were utilised to determine whether structural determinants were associated with lower psychological distress levels. Findings Our results revealed that over a quarter (26%) of trans participants did not feel New Zealand law protects against discrimination for being trans or non-binary. Trans participants reported heightened levels of distrust compared to the general populations across media (65% vs 39%; RR= 1.66) parliament (52% vs 25%; RR = 2.07), police (49% vs 7%; RR = 7.48), and courts (48% vs 13%; RR = 3.84). Significant demographic differences in institutional trust levels were observed, with younger individuals, trans men, non-binary people assigned female at birth, or people with a disability status reporting lower trust toward different institutions. Perceived legal protection and confidence were correlated with lower psychological distress levels, and institutional trust partially mediated this association. Conclusions Findings from this study demonstrate the urgency for government agencies to consult appropriately and work collaboratively with trans communities to identify current gaps in laws and policies that protect the human rights of trans people. Trans-inclusive policies have the potential to elevate community trust toward institutions and improve the meaningful participation of trans people and address inequities.

Determinants of Capital Structure from Malaysian Shariah-Compliant Food and Beverages Firms

This paper addresses the dearth of empirical research on the capital structure of Shariah-compliant food and beverage (F&amp;B) firms in Malaysia. Despite the industry's dynamic growth, specific financing needs, and adherence to Shariah principles, a comprehensive investigation into the determinants of their capital structure choices is lacking. By exploring factors such as profitability, tangibility, growth opportunities, liquidity, and firm size, this paper aims to provide valuable insights into the financial strategies of these specific entities and fill crucial knowledge gaps in empirical evidence. The study employs panel data, a combination of cross-sectional and time-series data, with a sample comprising 24 Shariah-compliant F&amp;B firms listed on Bursa Malaysia, totalling 240 observations. Quantitative methods are applied using secondary data sourced from the Eikon database and financial statements in the annual reports of Bursa Malaysia-listed companies from 2013 to 2022. The findings reveal that profitability, tangibility, liquidity, and firm size significantly impact the capital structure choices of Shariah-compliant F&amp;B firms, while growth opportunities emerge as an insignificant factor. These results support the application of the trade-off theory for profitability and the pecking order theory for tangibility, liquidity, and firm size, shedding light on the nuanced financial decision-making processes within this sector.

A framework for assessing social structure in community governance of sustainable urban drainage systems: insights from a literature review

The utilization of Sustainable Urban Drainage Systems (SUDS) as Nature-based Solutions (NBS) holds significant promise for enhancing resilience against climate change-induced flooding and promoting community well-being in urban areas of Sub-Saharan Africa. While existing research predominantly emphasizes technical aspects within the NBS framework, understanding the socio-governance dynamics at the community level is equally imperative, particularly given the decentralized nature of SUDS. This study aims to complement the prevailing technical focus by examining the social dimensions of community governance related to SUDS implementation. Through a literature review, key determinants of social structure influencing successful community governance in SUDS management are identified, and categorized into actors, resources, discourses, and rules of engagement. An innovative assessment framework comprising 65 indicators is proposed to evaluate these determinants, offering a comprehensive tool for scholars and practitioners. By integrating social considerations into SUDS management practices, this research seeks to inform policy formulation and strategies tailored to Sub-Saharan African cities, facilitating equitable and participatory urban stormwater management initiatives crucial for addressing climate change challenges.

Variable CGRP family peptide signaling durations and the structural determinants thereof

Calcitonin gene-related peptides alpha and beta (αCGRP, βCGRP), adrenomedullin (AM), and adrenomedullin 2/intermedin (AM2/IMD) function in pain signaling, neuroimmune communication, and regulation of the cardiovascular and lymphatic systems by activating either of two class B GPCRs, CLR and CTR, in complex with a RAMP1, −2, or −3 modulatory subunit. Inspired by our recent discovery that AM2/IMD(1–47) activation of CLR-RAMP3 elicits long duration cAMP signaling, here we used a live-cell cAMP biosensor assay to characterize the signaling kinetics of the two CGRP peptides and several bioactive AM and AM2/IMD fragments with variable N-terminal extensions. Remarkably, AM2/IMD(8–47) and AM2/IMD-53 exhibited even longer duration signaling than the 1–47 fragment. AM2/IMD(8–47) was a striking 8-fold longer acting than AM(13–52) at CLR-RAMP3. In contrast, the N-terminal extension of AM had no effect on signaling duration. AM(1–52) and (13–52) were equally short-acting. Analysis of AM2/IMD-AM mid-region chimeras and AM2/IMD R23 and R33 point mutants showed the importance of these residues for long-duration signaling and identified AM2/IMD peptides that exhibited up to 17-fold diminished signaling duration at CLR-RAMP3, while retaining near wildtype signaling potencies. βCGRP was ∼ 3-fold longer acting than αCGRP at the CGRP (CLR-RAMP1) and the amylin1 (CTR-RAMP1) receptors. Chimeric CGRP peptides showed that the single residue difference near the N-terminus, and the two differences in the mid-region, equally contributed to the longer duration of βCGRP signaling. This work uncovers key temporal differences in cAMP signaling among the CGRP family peptides, elucidates the structural bases thereof, and provides pharmacological tools for studying long-duration AM2/IMD signaling.

Structural and functional insights into the enzymatic activities of lipases from Burkholderia stagnalis and Burkholderia plantarii.

Lipases with high interesterification activity are important enzymes for industrial use. The lipase from Burkholderia stagnalis (BsL) exhibits higher interesterification activity than that from Burkholderia plantarii (BpL) despite their significant sequence similarity. In this study, we determined the crystal structure of BsL at 1.40 Å resolution. Utilizing structural insights, we have successfully augmented the interesterification activity of BpL by over twofold. This enhancement was achieved by substituting threonine with serine at position 289 through forming an expansive space in the substrate-binding site. Additionally, we discuss the activity mechanism based on the kinetic parameters. Our study sheds light on the structural determinants of the interesterification activity of lipase.

Biophysical and structural study of La Crosse virus endonuclease inhibition for the development of new antiviral options.

The large Bunyavirales order includes several families of viruses with a segmented ambisense (-) RNA genome and a cytoplasmic life cycle that starts by synthesizing viral mRNA. The initiation of transcription, which is common to all members, relies on an endonuclease activity that is responsible for cap-snatching. In La Crosse virus, an orthobunyavirus, it has previously been shown that the cap-snatching endonuclease resides in the N-terminal domain of the L protein. Orthobunyaviruses are transmitted by arthropods and cause diseases in cattle. However, California encephalitis virus, La Crosse virus and Jamestown Canyon virus are North American species that can cause encephalitis in humans. No vaccines or antiviral drugs are available. In this study, three known Influenza virus endonuclease inhibitors (DPBA, L-742,001 and baloxavir) were repurposed on the La Crosse virus endonuclease. Their inhibition was evaluated by fluorescence resonance energy transfer and their mode of binding was then assessed by differential scanning fluorimetry and microscale thermophoresis. Finally, two crystallographic structures were obtained in complex with L-742,001 and baloxavir, providing access to the structural determinants of inhibition and offering key information for the further development of Bunyavirales endonuclease inhibitors.