Comparative Structural Analysis Research Articles

Three Polyhedron-Based Metal-Organic Frameworks Exhibiting Excellent Acetylene Selective Adsorption.

The separation of acetylene (C2H2) from ethylene (C2H4) and ethane (C2H6) is crucial for the production of high-purity C2H2 and the recovery of other gases. Polyhedron-based metal-organic frameworks (PMOFs) are characterized by their spacious cavities, which facilitate gas trapping, and cage windows with varying sizes that enable gas screening. In this study, we carefully selected a class of PMOFs based on V-type tetracarboxylic acid linker (JLU-Liu22 containing benzene ring, JLU-Liu46 containing urea group and recombinant reconstructed In/Cu CBDA on the basis of JLU-Liu46) to study the relationship between pore environment and C2 adsorption and separation performance. Among the three compounds, JLU-Liu46 exhibits superior selectivity toward C2H2/C2H4 (2.06) as well as C2H2/C2H6 (2.43). Comparative structural analysis reveals that the exceptional adsorbed-C2H2 performance of JLU-Liu46 can be attributed to the synergistic effects arising from coordinatively unsaturated Cu sites combined with an optimal pore environment (matched pore size and polarity, urea functional group), resulting in a strong affinity between the framework and C2H2 molecules. Furthermore, transient breakthrough simulations of JLU-Liu46 confirmed its potential for separating C2H2 in ternary C2 gas.

BESO and SESO: Comparative Analysis of Spatial Structures Considering Self-Weight and Structural Reliability

A comparative analysis between Bidirectional Evolutionary Structural Optimization (BESO) and Smoothing-ESO (SESO), simultaneously considering Reliability-Based Topology Optimization (RBTO) and the structure’s self-weight in the case of three-dimensional elasticity, is presented in this study. Due to the important role of the existence of uncertainties in making the structural design more realistic, geometry, volumetric fraction, modulus of elasticity, compliance, and loading are considered random variables with normal probability distribution. When adopting the First Order Reliability Method (FORM), the failure probability is calculated based on the reliability index. Furthermore, considering the influence of self-weight in problems involving large structures in civil engineering, especially in the case of bridges, this makes the optimal configuration more reliable for design. A series of examples are covered to validate the methods presented, showing their efficiency and robustness.

Features of the part-speech composition of terms of international air law in English and Russian languages

The work reveals a problem of the part-of-speech composition in terms of the English and Russian languages in international air law. The study presents an analysis of the parts of speech included in the term structure in international air law according to the criterion of certain terminological field. The purpose of the study is to determine the most characteristic part-of-speech composition for the terms of several groups, identified on the basis of a common field in terminological systems Russian and English. This principle of analysis helps to compare terminological groups in different language systems. The objectives of the study were to identify the frequency of a certain part-ofspeech structure for the terms of the Russian and English languages. The work presents an empirical study, which prove that the proposed version of the analysis makes it possible to compare each lexical and semantic group in the English language with the Russian language in terms of the frequency of a certain part-of-speech structure; to identify the main dynamics in certain part-ofspeech structures in the English and Russian terminological systems of international air law. Based on the results of the study, the following conclusions were made: comparative analysis of the partof-speech structure based on the criterion of a single semantic core within the branch of international air law is the most objective criterion that allows the comparison of terms from two different language systems within the framework of cross-linguistic research; part-of-speech structures of terms are directly related to the structural features of the Russian and English languages.

Comparative analysis of steel bar structures of solar canopies composed of hyperbolic paraboloid units using genetic algorithms

Building integrated photovoltaics (BIPV) understood as an integral building component, is becoming more and more popular. In turn, the use of BIPV on curvilinear roofs is an interdisciplinary issue covering geometry, environmental engineering, architecture and construction. The article presents an approach to designing efficient steel bar structures of the modular solar canopies using genetic algorithms and their evaluation. Shaping effective forms of solar roofs was subordinated to the idea “form follows environment” in the original way as the roof form, and thus the shape of the structure depended on the amount of solar energy absorbed by the roof surface. The structures designed on a regular polygon plan were created from three, four, five, or six hyperbolic paraboloid (HP) modules arranged radially. Algorithmic definitions of their forms made it possible to obtain many variants of canopies with the adopted preliminary criteria, as well as to conduct genetic optimization, which helped to obtain the best results. For the best solutions in terms of geometrical forms, structural optimization was carried out due to the structures’ minimum masses. As a comparative criterion of structural effectiveness, a coefficient was used that specified the mass of the considered structure per square meter of the covered area. The proposed shaping method may constitute some guidelines for rational shaping of the steel bar structures with radially arranged modules, in which their effectiveness can be established already at the initial design stage. However, the best optimization results, that is, efficient and aesthetic canopies, can be ecological solutions to be used in practice.

The polinton-like supergroup of viruses: evolution, molecular biology, and taxonomy.

SUMMARYPolintons are 15-20 kb-long self-synthesizing transposons that are widespread in eukaryotic, and in particular protist, genomes. Apart from a transposase and a protein-primed DNA polymerase, polintons encode homologs of major and minor jelly-roll capsid proteins, DNA-packaging ATPases, and proteases involved in capsid maturation of diverse eukaryotic viruses of kingdom Bamfordvirae. Given the conservation of these structural and morphogenetic proteins among polintons, these elements are predicted to alternate between transposon and viral lifestyles and, although virions have thus far not been detected, are classified as viruses (class Polintoviricetes) in the phylum Preplasmiviricota. Related to polintoviricetes are vertebrate adenovirids; unclassified polinton-like viruses (PLVs) identified in various environments or integrated into diverse protist genomes; virophages (Maveriviricetes), which are part of tripartite hyperparasitic systems including protist hosts and giant viruses; and capsid-less derivatives, such as cytoplasmic linear DNA plasmids of fungi and transpovirons. Phylogenomic analysis indicates that the polinton-like supergroup of viruses bridges bacterial tectivirids (preplasmiviricot class Tectiliviricetes) to the phylum Nucleocytoviricota that includes large and giant eukaryotic DNA viruses. Comparative structural analysis of proteins encoded by polinton-like viruses led to the discovery of previously undetected functional domains, such as terminal proteins and distinct proteases implicated in DNA polymerase processing, and clarified the evolutionary relationships within Polintoviricetes. Here, we leverage these insights into the evolution of the polinton-like supergroup to develop an amended megataxonomy that groups Polintoviricetes, PLVs (new class 'Aquintoviricetes'), and virophages (renamed class 'Virophaviricetes') together with Adenoviridae (new class 'Pharingeaviricetes') in a preplasmiviricot subphylum 'Polisuviricotina' sister to a subphylum including Tectiliviricetes ('Prepoliviricotina').

Enhancement of the structural behavior of elevated water tanks using X-plate dampers

This study aims at utilizing of X-plate dampers to effectively address vibrations and minimize the possible structural harm to water tank facilities, and also at utilizing a finite element methodology to simulate and analyze the structural reactions. A non-linear time history analysis is employed to assess the effectiveness of X-plate dampers when subjected to different blast-induced ground motions. The efficiency of dampers was evaluated by conducting a comparative analysis of liquid storage structures with and without dampers using 50 m3 and 1500 m3 tanks in empty and full conditions. X – plate dampers are installed in a variety of bracing schemes, such as diagonal, X, V, Inverted V, and K bracing subjected to underground blast loads to improve the resilience of the selected elevated water tanks. The results showed the X-bracing pattern is the most effective configuration for X-plate dampers in mitigating blast loads in a 50 m3 elevated tank without water, resulting in a reduction of displacement, shear force, and bending moment by 43%, 15%, and 22%, in case of elevated tank with water reduced by 39% 25% and 33% respectively. In 1500 m3 elevated tank without water, the K-bracing is determined to be the most effective type of bracing, reducing the displacement, shear force, and bending moment by 50%, 70%, and 70%, in case of elevated tank with water reduced by 53%, 52%, and 54% respectively. The current study makes a significant contribution to the field of structural engineering by providing useful insights into raised water tank construction.

Class B1 GPCRs: Insights into Multi-Receptor Pharmacology for the Treatment of Metabolic Disease.

The secretin-like, class B1 sub-family of seven transmembrane-spanning G protein coupled receptors (GPCRs) consists of 15 members that coordinate important physiological processes. These receptors bind peptide ligands and utilize a distinct mechanism of activation that is driven by evolutionarily conserved structural features. For the class B1 receptors, the C-terminus of the cognate ligand is initially recognized by the receptor via a large N-terminal extracellular domain that forms a hydrophobic ligand binding groove. This binding enables the N-terminus of the ligand to engage deep into a large volume, open transmembrane pocket of the receptor. Importantly, the phylogenetic basis of this ligand-receptor activation mechanism has provided opportunities to engineer analogues of several class B1 ligands for therapeutic use. Among the most successful of these are drugs targeting the glucagon-like peptide-1 (GLP-1) receptor for the treatment of type 2 diabetes and obesity. Recently, multi-functional agonists possessing activity at the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor, such as tirzepatide, and others that also contain glucagon receptor activity, have been developed. In this article, we review members of the class B1 GPCR family with focus on receptors for GLP-1, GIP, and glucagon, including their signal transduction and receptor trafficking characteristics. The metabolic importance of these receptors is also highlighted, along with the benefit of poly-pharmacologic ligands. Further, key structural features and comparative analyses of high-resolution cryogenic electron microscopy structures for these receptors in active-state complex with either native ligands or multi-functional agonists are provided, supporting the pharmacological basis of such therapeutic agents.

Market Squares of Small Towns as Public Space of Opole Silesia on Selected Examples (Legal Status After 2015)

This paper presents the results of research on the diagnosis of the state of public space in the context of the evolution of its structure, on the example of market squares of small cities. The background to the research is the implementation of the Act on Ensuring Accessibility for Persons with Special Needs (The Accessibility Act, 2019) and the Revitalisation Act (2015), as documents with significant impact on the shape of public spaces in Polish cities. The multicultural and cross-border region of Opole Silesia was chosen as the research area. Six small towns in the region, whose market squares have undergone a revitalization in recent years, were selected for analysis: Biała, Dobrodzień, Korfantów, Otmuchów, Paczków, Ujazd. This article aims to diagnose the condition of public space, on the example of the market squares of small towns, based on the solutions adopted in the revitalization projects. The criteria adopted for the analyses are the identity of the place and continuity of development, accessibility, and adaptation to climate change. The research uses the method of comparative analysis of the morphological structure, the method of analyzing the physical parameters of space, and the analysis of historical iconography and cartography. Conducted analyses will make it possible to formulate an answer to the question of to what extent the introduction of the regulations as mentioned above has changed the approach to the revitalization process as a continuation of the historically formed way of building the urban fabric, and to what extent it has forced the introduction of solutions that violate the continuity of historical development. The result of the research will be a diagnosis of the problems in the revitalization processes of small towns in the multicultural area of the Opole region, in the context of current legal conditions, and sustainable development.

Food retail in rural areas: Choosing the optimal format

Tightening competition among food retailers stimulates them to develop new formats of stores for urban spaces, which also can be economically efficient in rural areas. Appearance of a new format of stores that excites clientele’s interest and is able to compete with pick-up points and liquor stores may become a key to the domination in the market. The paper examines the prospects of creating an optimal format for food retailers that hold potential for spread in rural areas. Methodologically, the study relies on a systems approach, the cyclical theory of retail, and spatial development theories. The method encompasses three stages: first, holding a comparative analysis of the format structure of food retailers for 2015–2023; second, evaluating the territorial distribution of the two formats of retail chains (hard discounters and convenience stores) using the case of Volga and Ural Federal Districts; third, determining new formats of retail chains outside cities. Based on the analysis of market trends in the development of retail chain stores the paper suggests a conceptual model of the optimal retail format for rural areas with respect to product range, pricing, distribution of sales area, and additional services. The suggestions about the improvements in the model of the retail format for rural areas may spur the retail trade growth and promote the development of trade infrastructure outside urban areas.

Advances in Label-Free Glucose Detection Using Self-Assembled Nanoparticles and Surface-Enhanced Raman Spectroscopy.

In the landscape of biomolecular detection, surface-enhanced Raman spectroscopy (SERS) confronts notable obstacles, particularly in the label-free detection of biomolecules, with glucose and other sugars presenting a quintessential challenge. This study heralds the development of a pioneering SERS substrate, ingeniously engineered through the self-assembly of nanoparticles of diverse sizes (Ag1@Ag2NPs). This configuration strategically induces 'hot spots' within the interstices of nanoparticles, markedly amplifying the detection signal. Rigorous experimental investigations affirm the platform's rapidity, precision, and reproducibility, and the detection limit of this detection method is calculated to be 6.62 pM. Crucially, this methodology facilitates nondestructive glucose detection in simulated samples, including phosphate-buffered saline and urine. Integrating machine learning algorithms with simulated serum samples, the approach adeptly discriminates between hypoglycemic, normoglycemic, and hyperglycemic states. Moreover, the platform's versatility extends to the detection and differentiation of monosaccharides, disaccharides, and methylated glycosides, underscoring its universality and specificity. Comparative Raman spectroscopic analysis of various carbohydrate structures elucidates the unique SERS characteristics pertinent to these molecules. This research signifies a major advance in nonchemical, label-free glucose determination with enhanced sensitivity via SERS, laying a new foundation for its application in precision medicine and advancing structural analysis in the sugar domain.

Are Active Users the Most Central to Hacker Social Networks? A Comparative Analysis of Public and Private Online Network Structures Among Hackers

ABSTRACT The last decade witnessed significant research of user behavior and social networks within online hacker forums and illicit markets. Researchers have used the quantifiable nature of forum posting behaviors to assess network ties between actors and identify key participants based on their connections. These studies are based on the publicly identifiable associations between actors in public posts. Participants within forums can also connect with users through private messaging systems linking users directly through a sort of e-mail-based exchange. Few have considered how the public and private message networks of actors differ and what can be gleaned from their analysis. This study employed a quantitative analysis of a highly popular web forum used by hackers involved in both legal and criminal hacks. First, the networks were built of the relationships between 1,313 users across 12,531 threads and 19,862 public posts, and between those users’ 1,738 private messages. Then the centrality on hidden networks was estimated from the centrality on the visible networks. The implications of this study for policy and our understanding of online network structures are discussed.

Comparative Anatomical Analysis of Bark Structure in 10 Quercus Species.

Detailed anatomical features of bark are used and interpreted in plant taxonomy, phylogenetics, and other areas of plant science. However, the delicate nature of bark cells, combined with the difficulty of obtaining high-quality sections and reliable data, limits the potential for utilizing and processing bark. In this study, the anatomical structure of the bark of 10 Quercus species growing in Yunnan Province, China, was characterized in detail. The results indicate that the anatomical features of the barks of 10 Quercus spp. show a certain degree of consistency. Specifically, sieve tubes are distributed in solitary elements or in small groups, mostly as compound sieve plates containing 2-8 sieve areas, suggesting that Quercus spp. may occupy a conservative evolutionary position. Additionally, for the first time, this study reports the presence of simple sieve plates in the sieve tube elements of Quercus phloem. Each sieve tube element has a companion cell on one side. The companion cell strands contain 2-7 cells. Axial parenchyma is diffuse, with parenchyma strands typically consisting of 4-7 cells; druses are present within chambered crystalliferous cells. Phloem rays are of two distinct sizes and often exhibit dilatation and sclerification, and the ray composition consists of procumbent cells. Sclerenchyma is composed of fibers and sclereids, both of which contain prismatic crystals. Most of the fibers are gelatinous fibers, which are distributed in discontinuous tangential bands of about five cells in width. Sclereids appear in clusters. The presence of sclerenchyma provides mechanical support to the bark, reducing the collapse of the phloem. Periderm usually consists of around 10-30 layers of phellem, and Quercus acutissima and Q. variabilis can reach dozens or hundreds layers. The phelloderm typically consists of from two to five layers, with Q. variabilis having up to ten or more layers. The filling tissue of lenticels in all Quercus species is nonstratified (homogeneous) and largely nonsuberized. Overall, this study enriches our comprehension of Quercus bark anatomy, elucidating evolutionary patterns, functional adaptations, and ecological ramifications within this significant botanical genus.

Comparative structural analysis of anhydrous and monohydrated polymorphs of diclofenac diethylammonium: Implications for stability, dissolution, and bioavailability

Diclofenac diethylammonium belongs to the class of non-steroidal anti-inflammatory drugs, and it is widely used to relieve pain and reduce systemic inflammation. This drug exists in polymorphic forms, which can directly affect the ability to process the drug, as well as drug product dissolution, stability, and bioavailability. Considering the worldwide regulatory guidance for polymorphs in drug substances, a detailed structural analysis of two polymorphs exhibiting the anhydrous and monohydrated structures of diclofenac diethylammonium is presented here, using the supramolecular arrangement and its relationship with structural-physicochemical properties. The polymorph’s structures show conformational differences in the carboxylic group caused by coordinated water molecules presented in the monohydrated polymorphic structure. Both polymorphs have the supramolecular arrangement stabilized by NH···O and CH···Cl intermolecular interactions, but the monohydrated molecule presents a strong OH···O intermolecular interaction due to the presence of a water molecule. Hirshfeld surface analysis showed CH···π and π···π contacts in the anhydrous and monohydrated polymorphs, respectively. Theoretical results, including solvent effect with explicit and implicit approaches for water, indicated the kinetic stability of the diclofenac diethylammonium drug and showed susceptible electrophilic attacks occurring in the region close to the carbonyl oxygen atom.

Molecular insights into the initiation step of the Rcs signaling pathway.

The Rcs pathway is repressed by the inner membrane protein IgaA under non-stressed conditions. This repression is hypothesized to be relieved by the binding of the outer membrane-anchored RcsF to IgaA. However, the precise mechanism by which RcsF binding triggers the signaling remains unclear. Here, we present the 1.8Å resolution crystal structure capturing the interaction between IgaA and RcsF. Our comparative structural analysis, examining both the bound and unbound states of the periplasmic domain of IgaA (IgaAp), highlights rotational flexibility within IgaAp. Conversely, the conformation of RcsF remains unchanged upon binding. Our invivo and invitro studies do not support the model of a stable complex involving RcsF, IgaAp, and RcsDp. Instead, we demonstrate that the elements beyond IgaAp play a role in the interaction between IgaA and RcsD. These findings collectively allow us to propose a potential mechanism for the signaling across the inner membrane through IgaA.

Thermo-Mechanical Properties of Particulate Banana Epoxy Composite with Fruit Waste (Dragon Fruit Peel) Micro Filler for Household Applications

This study evaluates the thermo-mechanical characteristics of eco-friendly composite made of particulate banana fiber (reinforcement), epoxy resin (matrix) and dragon fruit peel powder (micro filler). The composites were developed using compression moulding technique with 3 factors, 4 variations and Taguchi orthogonal array design (L16). The proposed filler characterization results revealed that the density was 0.97 g/cm3 and combination of C–O, Ca–O, and Ca–Co could improve mechanical strength. Composites with 5 mm fiber length, 40 wt.% fiber weight, and 15 wt.% filler weight have a maximum tensile strength of 25.58 MPa, flexural strength of 44.47 MPa, impact strength 180.33 J/m, and hardness of 82.50 SD. The best composite’s thermal, wear, water and fatigue studies were proposed to suit household applications. The proposed filler improves fiber-resin bonding, which increases thermal stability to 245 °C, wear resistance, decreases water absorption, and results in a fatigue life count of 121000 cycles. Thus, this study concluded that the increasing filler content and decreasing particulate size had an impact on the thermo-mechanical characteristics of banana-reinforced polymeric composites. As a result, an eco-friendly polymeric composite mixer coupler model was developed. Comparative structural and model analyses were performed using ANSYS R17.2. The analysis results confirmed that the proposed composite had higher natural frequencies of 2766.5 Hz and lower deformation values of 0.089293 mm. This proves the proposed eco-friendly composite is a suitable replacement for a synthetic mixer coupler.

Structural insights and functional characterization of a novel β-glucosidase derived from Thermotoga profunda

β-Glucosidase is a crucial cellulase, as its activity determines the efficiency of cellulose hydrolysis into glucose. This study addresses the functional and structural characteristics of Thermotoga profunda β-glucosidase (Tp-BGL). Tp-BGL exhibited a Km of 0.3798 mM for p-nitrophenyl-β-d-glucopyranoside (pNPGlc) and 4.44 mM for cellobiose, with kcat/Km of 1211.16 and 4.18 s−1 mM−1, respectively. In addition, Tp-BGL showed significant pH adaptability and thermal stability, with a Tm of 85.7 °C and retaining >90 % of its activity after incubation at 80 °C for 90 min. The crystal structure of Tp-BGL was resolved at 1.95 Å resolution, and reveals a typical TIM barrel structure. Comparative structural analysis highlighted that the major distinction between Tp-BGL and the other glucosidases lies in their loop regions.

OBTAINING NANOCELLULOSE FROM BIOMASS AND STUDY OF THEIR PHYSICOCHEMICAL PROPERTIES

This work describes the production of nanocellulose by removing lignin from biomass by the peroxide method in the presence of an H2SO4 catalyst and the study of its physicochemical properties. The structure of cellulose and modified nanocellulose was studied using Raman spectroscopy, IR (infrared) spectroscopy, X-ray diffraction, and SEM (scanning electron microscopy). The resulting increase in the crystallinity of NFC (nanofibrous cellulose) was confirmed by X-ray diffraction analysis. This indicates that cellulose was associated with the removal of amorphous parts. As a result of X-ray diffraction, overlap on NFC radiographs occurred even in the area of intense lines. In the sample obtained by IR spectroscopy, the presence of groups (3413.12 cm−1; 2918.34 cm−1; 1373.30 cm−1; 617.52 cm−1) corresponding to the nature of NFC was detected. Strong absorption at 1429.8 cm−1 in the spectrum of CMC (carboxylmethylcellulose) revealed –COOH groups, indicating successful carboxylation of cellulose. The morphological surface, average particle size and structure of the samples were studied. As a result of a comparative analysis of morphological structures, an ordered filamentous structure of nanofibrous cellulose characteristic of fibers and a porous structure of CMC with a modified surface and uneven fibers were revealed. The developed method for producing modified cellulose from biomass does not require multi-stage processing compared to traditional methods and is safe for the environment. It has been shown that it is possible to obtain high-quality cellulose in one stage without the use of reagents containing sulfur and chlorine, high pressure and high water consumption.

Comparative electronic structure, magnetic and optical properties of cubic perovskite BaXO3 (X=Ti, Sn) with self-defects: A first-principles calculation

In this work, a comparative analysis of the electronic structures and various optical properties of perovskite BaTiO3 and BaSnO3 with self-defects was estimated via DFT calculations. Although both materials are categorized as semiconductors, they exhibit significant differences in band gap values. BaTiO3 possesses a band gap of 1.75 eV, whereas BaSnO3 has a substantially lower band gap of only 0.43 eV. Despite both BaTiO3 and BaSnO3 being nonmagnetic materials, defects can lead to nonzero magnetic moments. For BaTiO3, oxygen vacancies and Ti interstitial strongly induce a magnetic moment of 0.35 μB/f.u. and 0.57 μB/f.u., respectively. In contrast, BaSnO3 shows large magnetic moments of 0.50 μB/f.u. for Ba and Sn interstitials and 0.47 μB/f.u. for O interstitial. We expected that our findings would promote the application of BaTiO3 and BaSnO3 materials not only as semiconductors but also as extensions for ferromagnetic semiconductor materials.

Поведенческая экономика в контексте кризисной ситуации: исследования и выводы

This article is devoted to the problems of behavioral economics, which defines the boundaries of rational consumer choice and studies models and scenarios of consumer behavior. The author examined the features of consumer behavior in the context of economic and geopolitical crises that modern Russia has gone through from the 1990s to the present. The article provides a periodization of crises, taking into account their specifics, causes and consequences. The research included an analysis of models and scenarios of consumer behavior during the acute phase of the crisis period in 2022, a comparative analysis of the cost structure; indices of the decline and growth of spending on the main categories of goods and services were given, and the readiness of consumers to refuse purchases was analyzed. Significant attention in the work was paid to a comparative analysis of the main trends in consumer behavior during the crisis of 1997–1998 and the crisis of 2022, during which it was noted that consumer behavior is influenced by the increased maturity of markets and the preparedness of the public administration system for crisis situations. It is concluded that it is necessary to take into account the growing role of consumer behavior that deviates from the usual rational models, which emphasizes the need to develop new forms for building the economic policy of government bodies. In conclusion, the author focuses special attention on the fact that when making management decisions on the formation of programs to support industries and sectors of the economy, it is necessary to take into account emerging models and scenarios of consumer behavior.

Structural basis for the transport and regulation mechanism of the Multidrug resistance-associated protein 2.

Multidrug resistance-associated protein 2 (MRP2) is an ATP-powered exporter important for maintaining liver homeostasis and a potential contributor to chemotherapeutic resistance. Deficiencies in MRP2 function are associated with Dubin-Johnson Syndrome and increased vulnerability to liver injury from cytotoxic drugs. Using cryogenic electron microscopy (cryo-EM), we determined the structures of human MRP2 in three conformational states: an autoinhibited state, a substrate-bound pre-translocation state, and an ATP-bound post-translocation state. These structures show that MRP2 functions through the classic alternating access model, driven by ATP binding and hydrolysis. Its cytosolic regulatory (R) domain serves as a selectivity gauge, wherein only sufficiently high concentrations of substrates can effectively compete with and disengage the R domain to initiate transport. Comparative structural analyses of MRP2 in complex with different substrates reveal how the transporter recognizes a diverse array of compounds, highlighting the transporter's role in multidrug resistance.