Structural Consequences Research Articles

Deciphering the Impact of Rare Missense Variants in EGFR-TKI-Resistant Non-Small-Cell Lung Cancer through Whole Exome Sequencing: A Computational Approach.

Targeted therapy revolutionizes the treatment of non-small-cell lung cancer (NSCLC), harboring molecular change. Epidermal growth factor receptor(EGFR) mutations play a crucial role in the development of NSCLC, serving as a pivotal factor in its pathogenesis. We elucidated the mechanisms of resistance and potential therapeutic strategies in NSCLC resistant to the EGFR-tyrosine kinase inhibitor (EGFR-TKI). This is achieved by identifying rare missense variants through whole exome sequencing (WES). The goal is to enhance our understanding, identify biomarkers, and lay the groundwork for targeted interventions, thereby offering hope for an improved NSCLC treatment landscape. We conducted WES analysis on 16 NSCLC samples with EGFR-TKI-resistant NSCLC obtained from SRA-NCBI (PRJEB50602) to reveal genomic profiles within the EGFR-TKI. Our findings showed that 48% of the variants were missense, and after filtering with the Ensembl variant effect predictor, 53 rare missense variants in 23 genes were identified as highly deleterious. Further examination using pathogenic tools like PredictSNP revealed 12 deleterious rare missense variants in 7 genes: ZNF717, PSPH, ESRRA, SEMA3G, PTPN7, CAVIN4, and MYBBP1A. Molecular dynamics simulation (MDS) suggested that the L385P variant alters the structural flexibility of ESRRA, potentially leading to unfolding of ERRα proteins. This could impact their function and alter ERRα expression. These insights from MDS enhance our understanding of the structural and dynamic consequences of the L385P ESRRA variant and provide valuable implications for subsequent therapeutic considerations and targeted interventions.

Police relationships and engagement with rural citizens: perspectives of front-line police in the United Kingdom, Australia, and France

PurposeThis article examines challenges and strategies related to police relationships and engagement with rural communities in England and Wales, Australia and France. It aims to bridge a gap in knowledge around how police balance public demands with organisational and contextual constraints, exploring the role of communication technology in overcoming geographical and cultural barriers in rural policing.Design/methodology/approachThe research draws upon 121 semi-structured interviews conducted across three distinct jurisdictions. In the United Kingdom and Australia, interviews were conducted via Microsoft Teams, while face-to-face interviews were conducted in France. Participants were recruited through the purposive sampling of police working in rural areas. The data were thematically analysed using NVivo Software.FindingsRural communities have low expectations of policing services, a consequence of geography, organisational structures and limited resource allocation. Building relationships can be challenging owing to isolation and terrain, the need for officers to have local and cultural knowledge, and difficulties in recruiting officers in rural posts. Technology-mediated communication has played a part in the solutions (e.g. social media). However, this may not always be suitable owing to limited connectivity, citizen and police preferences for communication and engagement, and the institutional and cultural nuances surrounding the application of technology.Originality/valueThis article provides empirical insights into the attitudes and experiences of rural police officers, highlighting the distinctive policing context and engagement needs of rural communities. The research underscores the necessity for contextually aware engagement. It suggests that while technology-mediated communication offers some solutions to spatial challenges, its effectiveness may be limited by access, generational preferences and the adaptability of police institutions and cultures.

Breakdown of Ohm's Law in Molecular Junctions with Electrodes of Single-Layer Graphene.

For sufficiently low biases, Ohm's law, the cornerstone of electricity, stating that current I and voltage V are proportional, is satisfied at low biases for all known systems ranging from macroscopic conductors to nanojunctions. In this study, we predict theoretically and demonstrate experimentally that in single-molecule junctions fabricated with single-layer graphene as electrodes the current at low V scales as the cube of V, thereby invalidating Ohm's law. The absence of the ohmic regime is a direct consequence of the unique band structure of the single-layer graphene, whose vanishing density of states at the Dirac points precludes electron transfer from and to the electrodes at low biases.

Marine heatwaves disrupt ecosystem structure and function via altered food webs and energy flux

The prevalence and intensity of marine heatwaves is increasing globally, disrupting local environmental conditions. The individual and population-level impacts of prolonged heatwaves on marine species have recently been demonstrated, yet whole-ecosystem consequences remain unexplored. We leveraged time series abundance data of 361 taxa, grouped into 86 functional groups, from six long-term surveys, diet information from a new diet database, and previous modeling efforts, to build two food web networks using an extension of the popular Ecopath ecosystem modeling framework, Ecotran. We compare ecosystem models parameterized before and after the onset of recent marine heatwaves to evaluate the cascading effects on ecosystem structure and function in the Northeast Pacific Ocean. While the ecosystem-level contribution (prey) and demand (predators) of most functional groups changed following the heatwaves, gelatinous taxa experienced the largest transformations, underscored by the arrival of northward-expanding pyrosomes. We show altered trophic relationships and energy flux have potentially profound consequences for ecosystem structure and function, and raise concerns for populations of threatened and harvested species.

Mapping the APOE structurally on missense variants in elderly Brazilians

Cardiovascular diseases (CVDs) pose a significant global health threat, with familial hypercholesterolemia (FH) being a key genetic contributor. The apolipoprotein E (APOE) gene plays a vital role in lipid metabolism, and its variants are associated with CVD risk. This study explores prevalent APOE variants (p.R163C, p.R176C, p.R246C and p.V254E) using genetic and structural analyses. The research, initiated by identifying high-frequency APOE variants through the ABraOM database, utilizes homology modeling and molecular dynamics (MD) simulations to understand the structural consequences. The major lipid-binding region, a critical domain for lipid metabolism, was a focal point. Structural dynamics, including principal component analyses and domain movement analyses, highlighted distinct patterns in APOE variants compared to the wild type (WT). Results revealed significant differences in the structural behavior of variants, particularly in the Major lipid-binding region. The identification of an ‘elbow’ structure with two states (Elbow I and Elbow II) provided insights into conformational changes. Notably, variants exhibited unique patterns in hydrogen bonding (hb) and hydrophobic interactions, indicating potential functional consequences. The study further associated APOE variants with clinical outcomes, including cognitive impairment and cholesterol levels. Specific variants demonstrated correlations with cognitive decline and variations in lipid profiles, emphasizing their relevance to cardiovascular and neurobiological health. In conclusion, this integrated approach enhances our understanding of APOE variants, shedding light on their role in lipid metabolism and cardiovascular health. The identified structural ‘elbows’ and their association with clinical outcomes offer a nuanced perspective, guiding future research toward targeted interventions for diseases linked to lipid metabolism and neurobiology. Communicated by Ramaswamy H. Sarma

Abstract 1250 Biochemical Investigation on the Structural Consequences of Tandem Mutations Induced by the UV and Cadmium Exposure during DNA Replication

Abstract 1250 Biochemical Investigation on the Structural Consequences of Tandem Mutations Induced by the UV and Cadmium Exposure during DNA Replication

A Resource-Acquisition Perspective: Examining the Effects of Downsizing on Work-Related Relationships and Performance

Today’s corporations increasingly use downsizing as a change strategy to improve organizational performance. Although downsizing and employee networks have garnered attention from both scholars and practitioners, few studies have investigated the influence of downsizing on the temporal dynamics of communication networks among surviving employees or how changes in communication patterns in organizations affect performance. To study how downsizing affects layoff survivors—extending Conservation of Resources theory to longitudinal network and employee-performance data—we examine the impact of downsizing on both the behavioral and structural consequences in an organizational network and test whether temporal changes in network members’ degree centrality predict how employees who survive a downsizing event perform in their jobs. Results indicate that, during the period immediately following a downsizing event, survivors’ new tie-seeking behavior results in gains in degree centrality when compared with degree centrality before the downsizing or after organization routines stabilize. Moreover, survivors with lower pre-downsizing degree centrality achieved greater gains in degree centrality than those with higher degree centrality. We find that substantial gains in degree centrality are positively related to post-downsizing performance. Efforts to regain degree centrality are abandoned during the stabilization period, and changes in degree centrality are no longer positively related to post-downsizing performance. Our results demonstrate that dynamic changes in degree centrality during disruption and stabilization periods following a downsizing event have differential effects on work-related relationships and performance. We discuss the theoretical and managerial implications of these results and suggest future research directions.

FACTORS EFFECTING JOB SATISFACTION FOR ONLINE EDUCATION AMONG LECTURERS IN BANGLADESH

The global pandemic caused by Covid-19 infectious disease during the year 2020 has pierced the life of humankind in almost all countries and all members of the society. This pandemic issue limits one to cope with a changing work environment and it induces both structural and functional consequences on the education system. Thus, the online education system emerged and repositioned itself as one of the most effective mediums of education system recently. This study examined decision factors such as happiness, quality of work-life commitment and attitude toward online education and its influence on job satisfaction of academic staffs in Bangladesh. A quantitative research approach has been taken using a random sampling method to collect data from 293 lecturers working in colleges and universities in the metropolitan city of Dhaka. For the study, Exploratory Factor Analysis and Structural Equation Modelling techniques were performed. The findings helped in filling the satisfaction-behavioural gap in understanding attitude measures of academic staffs toward conducting courses in online mode.

VWD domain stabilization by autocatalytic Asp-Pro cleavage.

Domains known as von Willebrand factor type D (VWD) are found in extracellular and cell-surface proteins including von Willebrand factor, mucins, and various signaling molecules and receptors. Many VWD domains have a glycine-aspartate-proline-histidine (GDPH) amino-acid sequence motif, which is hydrolytically cleaved post-translationally between the aspartate (Asp) and proline (Pro). The Fc IgG binding protein (FCGBP), found in intestinal mucus secretions and other extracellular environments, contains 13 VWD domains, 11 of which have a GDPH cleavage site. In this study, we investigated the structural and biophysical consequences of Asp-Pro peptide cleavage in a representative FCGBP VWD domain. We found that endogenous Asp-Pro cleavage increases the resistance of the domain to exogenous proteolytic degradation. Tertiary structural interactions made by the newly generated chain termini, as revealed by a crystal structure of an FCGBP segment containing the VWD domain, may explain this observation. Notably, the Gly-Asp peptide bond, upstream of the cleavage site, assumed the cis configuration in the structure. In addition to these local features of the cleavage site, a global organizational difference was seen when comparing the FCGBP segment structure with the numerous other structures containing the same set of domains. Together, these data illuminate the outcome of GDPH cleavage and demonstrate the plasticity of proteins with VWD domains, which may contribute to their evolution for function in a dynamic extracellular environment.

Exploring the Influence of Zinc Ions on the Conformational Stability and Activity of Protein Disulfide Isomerase.

The interplay between metal ion binding and the activity of thiol proteins, particularly within the protein disulfide isomerase family, remains an area of active investigation due to the critical role that these proteins play in many vital processes. This research investigates the interaction between recombinant human PDIA1 and zinc ions, focusing on the subsequent implications for PDIA1's conformational stability and enzymatic activity. Employing isothermal titration calorimetry and differential scanning calorimetry, we systematically compared the zinc binding capabilities of both oxidized and reduced forms of PDIA1 and assessed the structural consequences of this interaction. Our results demonstrate that PDIA1 can bind zinc both in reduced and oxidized states, but with significantly different stoichiometry and more pronounced conformational effects in the reduced form of PDIA1. Furthermore, zinc binding was observed to inhibit the catalytic activity of reduced-PDIA1, likely due to induced alterations in its conformation. These findings unveil a potential regulatory mechanism in PDIA1, wherein metal ion binding under reductive conditions modulates its activity. Our study highlights the potential role of zinc in regulating the catalytic function of PDIA1 through conformational modulation, suggesting a nuanced interplay between metal binding and protein stability in the broader context of cellular redox regulation.

Light-sensitive phosphorylation regulates retinal IMPDH1 activity and filament assembly.

Inosine monophosphate dehydrogenase (IMPDH) is the rate-limiting enzyme in guanosine triphosphate (GTP) synthesis and assembles into filaments in cells, which desensitizes the enzyme to feedback inhibition and boosts nucleotide production. The vertebrate retina expresses two splice variants IMPDH1(546) and IMPDH1(595). In bovine retinas, residue S477 is preferentially phosphorylated in the dark, but the effects on IMPDH1 activity and regulation are unclear. Here, we generated phosphomimetic mutants to investigate structural and functional consequences of S477 phosphorylation. The S477D mutation resensitized both variants to GTP inhibition but only blocked assembly of IMPDH1(595) filaments. Cryo-EM structures of both variants showed that S477D specifically blocks assembly of a high-activity assembly interface, still allowing assembly of low-activity IMPDH1(546) filaments. Finally, we discovered that S477D exerts a dominant-negative effect in cells, preventing endogenous IMPDH filament assembly. By modulating the structure and higher-order assembly of IMPDH, S477 phosphorylation acts as a mechanism for downregulating retinal GTP synthesis in the dark when nucleotide turnover is decreased.

Conscientious objection and barriers to abortion within a specific regional context - an expert interview study.

While most countries that allow abortion on women's request also grant physicians a right to conscientious objection (CO), this has proven to constitute a potential barrier to abortion access. Conscientious objection is regarded as an understudied phenomenon the effects of which have not yet been examined in Germany. Based on expert interviews, this study aims to exemplarily reconstruct the processes of abortion in a mid-sized city in Germany, and to identify potential effects of conscientious objection. Five semi-structured interviews with experts from all instances involved have been conducted in April 2020. The experts gave an insight into the medical care structures with regard to abortion procedures, the application and manifestations of conscientious objection in medical practice, and its impact on the care of pregnant women. A content analysis of the transcribed interviews was performed. Both the procedural processes and the effects of conscientious objection are reported to differ significantly between early abortions performed before the 12th week of pregnancy and late abortions performed at the second and third trimester. Conscientious objection shows structural consequences as it is experienced to further reduce the number of possible providers, especially for early abortions. On the individual level of the doctor-patient relationship, the experts confirmed the neutrality and patient-orientation of the vast majority of doctors. Still, it is especially late abortions that seem to be vulnerable to barriers imposed by conscientious objection in individual medical encounters. Our findings indicate that conscientious objection possibly imposes barriers to both early and late abortion provision and especially in the last procedural steps, which from an ethical point of view is especially problematic. To oblige hospitals to partake in abortion provision in Germany has the potential to prevent negative impacts of conscientious objection on women's rights on an individual as well as on a structural level.

Development and outcomes of surgical and urological kidney transplantation programs in Germany: a total population analysis from 2006 to 2021

PurposeKidney transplantation (KT) is the most frequently performed organ transplantation. In Germany, KT is performed in urology and surgery departments with unknown consequences of this parallel structure. The aim of the study was to compare the development and outcome of KT in urology and surgery departments.MethodsOn an institutional level, we analyzed the annual caseload from 2006 to 2021 with the reimbursement. INFO tool based on hospitals’ quality reports (Reimbursement Institute, Hürth, Germany). For outcome comparison we extracted raw data from the transplantation centers' quality reports (Deutsche Stiftung Organtransplantation, DSO).ResultsA total of 23,599 cases (17,781 deceased donor and 5,818 living donor KTs) were included. The total number of KTs decreased from 1851 in 2006 to 1701 in 2021 (− 8%; p = 0.12). The total number of urological KTs decreased from 592 cases in 2006 to 395 cases in 2021 (− 33.3%; p = 0.01). Further analysis revealed no significant differences between intra- and postoperative complications and graft quality at one year for deceased donor KTs (DDKT) although differences in immediate renal function and graft quality at discharge could be observed. There were no significant differences in immediate renal function and graft quality at discharge for living donor KTs (LDKT) between the specialties.ConclusionKTs performed in urology departments declined between 2006 and 2021. Nevertheless, intra- and postoperative complications as well as long-term function did not differ between surgical and urological KT programs. Hence, an interdisciplinary approach, especially considering the upcoming challenges in KT as, e.g., robot-assisted surgery seems reasonable.

Probabilistic modelling of deterioration of reinforced concrete structures

Reinforced concrete (RC) structures deteriorate over time which affects their strength and serviceability. To develop measures for protecting new RC structures against deterioration and assess the condition of existing RC structures subjected to deterioration an understanding of the deterioration processes and the ability to predict their development, including structural consequences, are essential. This problem has attracted significant attention from researchers, including those working in the area of structural reliability (in particular within the JCSS) since there are major uncertainties associated with the deterioration processes and their structural effects. The paper presents an overview of the probabilistic modelling of various deterioration processes affecting RC structures such as corrosion of reinforcing steel, freezing-thawing, alkali-aggregate reaction, sulphate attack and fatigue, and their structural implications, including the historical perspective and current state-of-the-art. It also addresses the issues related to the inspection/monitoring of deteriorating RC structures and the analysis of collected data taking into account relevant uncertainties. Examples illustrating the application of the presented probabilistic models are provided. Finally, the current gaps in the knowledge related to the problem, which require further attention, are discussed.

Abstract TP21: Consequences of Atrial Fibrillation Burden on Deep Cerebral Hemodynamic Related Structural Brain Damage

Background: Recent data using ultrahigh-resolution brain MRI suggests that atrial fibrillation (AF) has adverse effects on wall shear stress and blood flow in lenticulostriate arteries (LSA). The structural consequences of such pathophysiological alterations and whether they contribute to cognitive impairment in AF are not known. We hypothesized that the AF burden is associated with the severity of MRI markers of ischemic and hemorrhagic injury related to LSA disease. Methods: We analyzed data from 560 patients with AF and no clinical history of stroke or neurodegenerative disease, who received brain MRIs at a tertiary referral center. Neuroimaging data were collected by a stroke neurologist who was blinded to the clinical data. The presence of paroxysmal/persistent vs permanent AF was the main measure of AF burden. The imaging outcome variables were counts of deep lacunes, deep cerebral microbleeds (dCMB), and presence of a peri-basal ganglia white matter hyperintensity pattern (peri-BG WMH). Results: The mean age of the 560 AF patients was 73 + 11 and 212 (38%) patients were female. Mean CHA 2 DS 2 -VASc was 3.4 + 1.5 and 86 (15.4%) had permanent atrial fibrillation. Deep lacunes were found in 26.6%, dCMBs in 6.3% and a peri-BG WMH pattern in 2.7% of patients. In univariate analyses, the presence of permanent AF was associated with higher mean deep lacune counts (0.84 vs 0.51, p=0.026), higher mean dCMB counts (0.25 vs 0.1, p=0.018), and peri-BG WMH pattern (7.1% vs 1.9%, p=0.016) when compared to paroxysmal/persistent AF. In separate multivariable analyses, permanent AF type remained an independent predictor of dCMBs (p=0.019) and peri-BG WMH pattern (p=0.028) after controlling for age, sex, and vascular risk factors. Permanent AF also showed a tendency for independent association with deep lacunes (p=0.06) in a similar model. Discussion: Our results show that AF burden independently correlates with parenchymal MRI markers of LSA disease in patients without history of stroke. Such deep brain damage might contribute to AF-induced cognitive changes. The effects of better rhythm control on visible brain damage and cognitive changes should be studied in randomized trials.

Assessment of the state of actual nutrition in the population of the Russian Federation

Introduction. There was conducted the study of the actual nutrition in the population of the Russian Federation in 2017–2021, including a study of its trend and compliance with recommended rational standards.
 Materials and methods. The study used information from the Federal State Statistics Service (Rosstat) on consumption in population of the Russian Federation of the main food groups in households in 2017–2021. The annual representative sample was forty seven thousand eight hundred households. A method used to analyze time series of consumption of basic food products and a comparison of actual nutrition with recommended rational standards was carried out for the whole country, Federal districts, and constituent entities of the Federation.
 Results. In the Russian Federation in 2021, compared to 2017, consumption of most major food groups decreased. Consumption of meat and meat products increased by 6.8%, eggs by 1.3%. Consumption of fish and fish products remained at the same level. The analysis shows a decline in the consumption of bread and bakery products in all federal districts, with the exception of the Far East (an increase of 1.6%); potatoes, vegetable oil, with the exception of the Far East (an increase of 0.8%). At the same time, there is an increase in the consumption of meat and meat products in all federal districts, with the exception of the Far Eastern (decrease by 13.6%). For other product groups, consumption variations were noted.
 Below the recommended rational norms, the Russian population consumes fish and fish products, potatoes, bread, and bakery products, milk and dairy products, vegetables, fruits and berries, eggs, and vegetable oil. At the same time, excessive consumption of sugar (3.8 times higher than the norm), meat and meat products (27% higher than the norm) were noted.
 In the Federal Districts, consumption of most major food groups is below the recommended rational standards. In all federal districts, consumption of meat and meat products, sugar and confectionery products has increased.
 Significant differences have been established in the compliance of consumption levels with recommended rational standards by the population of the constituent entities of the Russian Federation in 2021. In most regions of the Russian Federation, high consumption of meat and meat products by the population is noted. 
 All regions of the Federation have high consumption of sugar and confectionery products.
 Limitations. This study is limited by the size of the representative sample, which was 47.8 thousand households.
 Conclusion. The consequence of an irrational nutrition structure is a violation of the nutritional status, which is expressed in an increase in the prevalence among the population in recent years of such alimentary-dependent pathologies as obesity, hypertension, diabetes mellitus, and a number of others.

Algorithmic assessment reveals functional implications of GABRD gene variants linked to idiopathic generalized epilepsy

Objective The primary objective of this study is to address the challenge posed by the increasing number of variants of unknown clinical significance within the GABRD gene, which encodes the δ subunit of γ-Aminobutyric acid type A receptors. The focus is on predicting the most pathogenic GABRD VUS to enhance precision medicine and improve our understanding of relevant pathophysiology. Methods The study employs a combination of in silico algorithms to analyze 82 variants of unknown clinical significance of GABRD gene sourced from the ClinVar database. Initially, separate algorithms based on sequence homology are utilized to assess this variant set. Subsequently, consensus variants predicted as pathogenic undergo further evaluation through a web server employing an algorithm based on structural homology. The resulting 11 variants are then validated using in silico tools that assess variant effects based on genetic and molecular data. The evaluation includes consideration of disease association and protein stability due to amino acid substitutions. Results The study identifies specific variants (L111R, R114C, D123N, G150S, and L243P) in the coding region of the GABRD gene, which are predicted as deleterious by multiple algorithms. These variants are evolutionarily conserved, mapped onto the extracellular domain of the δ subunit, and associated with idiopathic generalized epilepsy. Conclusions The findings suggest structural or functional consequences that lead to pathogenicity, offering valuable insights for wet-lab experimentation. Besides, the findings contribute to the validation of clinically significant genetic variants in the GABRD gene, which is critical for epilepsy precision medicine.

A novel likely pathogenetic variant p.(Cys235Arg) of the MEN1 gene in multiple endocrine neoplasia type 1 with multifocal glucagonomas.

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine syndrome caused by pathogenic variants in MEN1 tumor suppressor gene. Diagnosis is commonly based on clinical criteria and confirmed by genetic testing. The objective of the present study was to report on a MEN1 case characterized by multiple pancreatic glucagonomas, with particular concern on the possible predisposing genetic defects. While conducting an extensive review of the most recent scientific evidence on the unusual glucagonoma familial forms, we analyzed the MEN1 gene in a 35-year-old female with MEN1, as well as her son and daughter, using Sanger and next-generation sequencing (NGS) approaches. We additionally explored the functional and structural consequences of the identified variant using in silico analyses. NGS did not show any known pathogenic variant in the tested regions. However, a new non-conservative variant in exon 4 of MEN1 gene was found in heterozygosity in the patient and in her daughter, resulting in an amino acid substitution from hydrophobic cysteine to hydrophilic arginine at c.703T > C, p.(Cys235Arg). This variant is absent from populations databases and was never reported in full papers: its characteristics, together with the high specificity of the patient's clinical phenotype, pointed toward a possible causative role. Our findings confirm the need for careful genetic analysis of patients with MEN1 and establish a likely pathogenic role for the new p.(Cys235Arg) variant, at least in the rare subset of MEN1 associated with glucagonomas.

Morphophonological Innovations in New Speakers’ Kashubian

New Speakers of minority languages are a special case which gives us a unique glimpse into variation and change. In such cases, language change at an accelerated pace tends to lead to profound changes in the structure of the language. Such developments are observable in Kashubian, a minority Slavic language spoken in East Pomerania. For the purpose of this study, spoken data consisting of responses to video stimuli was collected from a group of Kashubian speakers. Chosen morphophonological developments were analysed, especially repatterning and vowel substitution in nouns and verbs, as well as phonemic mergers and their consequences for the morphological structure.

Iron Sequestration by Murine Calprotectin Induces Starvation Responses in Pseudomonas aeruginosa.

Pathogen sensing by the mammalian host induces a pro-inflammatory response that involves release of the antimicrobial metal-sequestering protein calprotectin (CP, S100A8/S100A9 heterooligomer, MRP8/MRP14 heterooligomer) from neutrophils. Biochemical investigations on human CP (hCP) have informed the molecular basis of how this protein sequesters metal ions. Murine models of infection have provided invaluable insights into the ability of murine CP (mCP) to compete with bacterial pathogens for essential metal nutrients. Despite this extensive work, our knowledge of how mCP sequesters metals from bacterial pathogens and its impacts on bacterial physiology is limited. Moreover, whether mCP sequesters iron and induces iron-starvation responses in bacterial pathogens has not been evaluated. Here, we examine the ability of mCP to withhold iron from Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen that causes severe infections in immunocompromised individuals and cystic fibrosis patients. We demonstrate that mCP prevents iron uptake and induces iron-starvation responses in P. aeruginosa laboratory strains PA14 and PAO1 and the JSRI-1 clinical isolate from a cystic fibrosis patient. We also show that mCP prevents iron uptake and induces an iron-starvation response in the Gram-positive bacterial pathogen Staphylococcus aureus. The His6 site of mCP is the iron-sequestering site; it exhibits Ca(II)-dependent Fe(II) affinity and binds Fe(II) with subpicomolar affinity in the presence of excess Ca(II) ions. This work is important for understanding the structure, function, and physiological consequences of mCP and how the mammalian host and bacterial pathogens compete for essential metal nutrients.