Proteins-Structure Function and Bioinformatics最新文献

{"title":"Mechanistic Insight Into the Conformational Changes of Cas8 Upon Binding to Different PAM Sequences in the Transposon-Encoded Type I-F CRISPR-Cas System.","authors":"Amnah Alalmaie, Raed Khashan","doi":"10.1002/prot.26730","DOIUrl":"10.1002/prot.26730","url":null,"abstract":"<p><p>The INTEGRATE system is a gene-editing approach that offers advantages over the widely used CRISPR-Cas9 system. It does not introduce double strand breaks in the target DNA but rather integrates the desired DNA sequence directly into it. The first step in the integration process is PAM recognition, which is critical to understanding and optimizing the system. Experimental testing revealed varying integration efficiencies of different PAM mutants, and computational simulations were carried out to gain mechanistic insight into the conformational changes of Cas8 during PAM recognition. Our results showed that the interaction between Arg246 and guanine at position (-1) of the target strand is critical for PAM recognition. We found that unfavorable interactions in the 5'-AC-3' PAM mutant disrupted this interaction and may be responsible for its 0% integration efficiency. Additionally, we discovered that PAM sequences not only initiate the integration process but also regulate it through an allosteric mechanism that connects the N-terminal domain and the helical bundle of Cas8. This allosteric regulation was present in all PAMs tested, even those with lower integration efficiencies, such as 5'-TC-3' and 5'-AC-3'. We identified the Cas8 residues that are involved in this regulation. Our findings provide valuable insights into PAM recognition mechanisms in the INTEGRATE system and can help improve the gene-editing technology.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":"1428-1448"},"PeriodicalIF":3.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142019713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Myotubularin Related Proteins and the Untapped Interaction Potential of Their Disordered C-Terminal Regions.","authors":"Daniel Saar, Caroline L E Lennartsson, Philip Weidner, Elke Burgermeister, Birthe B Kragelund","doi":"10.1002/prot.26774","DOIUrl":"https://doi.org/10.1002/prot.26774","url":null,"abstract":"<p><p>Intrinsically disordered regions (IDRs) of proteins remain understudied with enigmatic sequence features relevant to their functions. Members of the myotubularin-related protein (MTMR) family contain uncharacterized IDRs. After decades of research on their phosphatase activity, recent work on the C-terminal IDRs of MTMR7 revealed new interactions and important new functions beyond the phosphatase function. Here we take a broader look at the C-terminal domains (CTDs) of 14 human MTMRs and use bioinformatic tools and biophysical methods to ask which other functions may be probable in this protein family. The predictions show that the CTDs are disordered and carry short linear motifs (SLiMs) important for targeting of MTMRs to defined subcellular compartments and implicating them in signaling, phase separation, interaction with diverse proteins, including transcription factors and are of relevance for cancer research and neuroscience. We also present experimental methods to study the CTDs and use them to characterize the coiled coil (CC) domains of MTMR7 and MTMR9. We show homo- and hetero-oligomerization with preference for MTMR7-CC to form dimers, while MTMR9-CC forms trimers. We relate the results to sequence features and make predictions for the structural landscape of other MTMRs. Our work gives a broad insight into the so far unrecognized features and SLiMs in MTMR-CTDs, and provides the basis for more in-depth experimental research on this diverse protein family and understudied IDRs in proteins in general.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142775190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The High-Resolution Structure of a Variable Lymphocyte Receptor From Petromyzon marinus Capable of Binding to the Brain Extracellular Matrix.","authors":"Elizabeth A Appelt, James B Thoden, Seth A Gehrke, Hannah D Bachmeier, Ivan Rayment, Eric V Shusta, Hazel M Holden","doi":"10.1002/prot.26768","DOIUrl":"10.1002/prot.26768","url":null,"abstract":"<p><p>Variable lymphocyte receptors (VLRs) are antigen receptors derived from the adaptive immune system of jawless vertebrates such as lamprey (Petromyzon marinus). First discovered in 2004, VLRs have been the subject of numerous biochemical and structural investigations. Due to their unique antigen binding properties, VLRs have been leveraged as possible drug delivery agents. One such VLR, previously identified and referred to as P1C10, was shown to bind to the brain extracellular matrix. Here, we present the high-resolution X-ray crystal structure of this VLR determined to 1.3 Å resolution. The fold is dominated by a six-stranded mixed β-sheet which provides a concave surface for possible antigen binding. Electron density corresponding to a 4-(2-hydroxyethyl)piperazine-1-propanesulfonic acid buffer molecule (HEPPS) was found in this region. By comparing the P1C10 molecular architecture and its buffer binding residues with those of other VLRs previously reported, it was possible to illustrate how this unique class of proteins can accommodate diverse binding partners. Additionally, we provide an analysis of the experimentally determined structure compared to the models generated by the commonly used AlphaFold and iTASSER structure prediction software packages.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142735033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using Short Molecular Dynamics Simulations to Determine the Important Features of Interactions in Antibody-Protein Complexes.","authors":"A Clay Richard, Robert J Pantazes","doi":"10.1002/prot.26773","DOIUrl":"https://doi.org/10.1002/prot.26773","url":null,"abstract":"<p><p>The last few years have seen the rapid proliferation of machine learning methods to design binding proteins. Although these methods have shown large increases in experimental success rates compared to prior approaches, the majority of their predictions fail when they are experimentally tested. It is evident that computational methods still struggle to distinguish the features of real protein binding interfaces from false predictions. Short molecular dynamics simulations of 20 antibody-protein complexes were conducted to identify features of interactions that should occur in binding interfaces. Intermolecular salt bridges, hydrogen bonds, and hydrophobic interactions were evaluated for their persistences, energies, and stabilities during the simulations. It was found that only the hydrogen bonds where both residues are stabilized in the bound complex are expected to persist and meaningfully contribute to binding between the proteins. In contrast, stabilization was not a requirement for salt bridges and hydrophobic interactions to persist. Still, interactions where both residues are stabilized in the bound complex persist significantly longer and have significantly stronger energies than other interactions. Two hundred and twenty real antibody-protein complexes and 8194 decoy complexes were used to train and test a random forest classifier using the features of expected persistent interactions identified in this study and the macromolecular features of interaction energy (IE), buried surface area (BSA), IE/BSA, and shape complementarity. It was compared to a classifier trained only on the expected persistent interaction features and another trained only on the macromolecular features. Inclusion of the expected persistent interaction features reduced the false positive rate of the classifier by two- to five-fold across a range of true positive classification rates.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142735041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling GPCRs Allosteric Modulation. Cannabinoid 1 Receptor as a Case Study.","authors":"Alejandro Cruz, Arieh Warshel","doi":"10.1002/prot.26762","DOIUrl":"https://doi.org/10.1002/prot.26762","url":null,"abstract":"<p><p>G-protein-coupled receptors (GPCRs) constitute one of the most prominent families of integral membrane receptor proteins that mediate most transmembrane signaling processes. Malfunction of these signal transduction processes is one of the underlying causes of many human pathologies (Parkinson's, Huntington's, heart diseases, etc), provoking that GPCRs are the largest family of druggable proteins. However, these receptors have been targeted traditionally by orthosteric ligands, which usually causes side effects due to the simultaneous targeting of homologous receptor subtypes. Allosteric modulation offers a promising alternative approach to circumvent this problematic and, thus, comprehending its details is a most important task. Here we use the Cannabinoid type-1 receptor (CB1R) in trying to shed light on this issue, focusing on positive allosteric modulation. This is done by using the protein-dipole Langevin-dipole (PDLD) within the linear response approximation (LRA) framework (PDLD/S-2000) along with our coarse-grained (CG) model of membrane proteins to evaluate the dissociation constants (K_Bs) and cooperativity factors (αs) for a diverse series of CB1R positive allosteric modulators belonging to the 2-phenylindole structural class, considering CP55940 as an agonist. The agreement with the experimental data evinces that significantly populated allosteric modulator:CB1R and allosteric modulator:CP55940:CB1R complexes have been identified and characterized successfully. Analyzing them, it has been determined that CB1R positive allosteric modulation lies in an outwards displacement of transmembrane α helix (TM) 4 extracellular end and in the regulation of the range of motion of a compound TM7 movement for binary and ternary complexes, respectively. In this respect, we achieved a better comprehension of the molecular architecture of CB1R positive allosteric site, identifying Lys192^3.28 and Gly194^3.30 as key residues regarding electrostatic interactions inside this cavity, and to rationalize (at both structural and molecular level) the exhibited stereoselectivity in relation to positive allosteric modulation activity by considered CB1R allosteric modulators. Additionally, putative/postulated allosteric binding sites have been screened successfully, identifying the real CB1R positive allosteric site, and most structure-activity relationship (SAR) studies of CB1R 2-phenylindole allosteric modulators have been rationalized. All these findings point out towards the predictive value of the methodology used in the current work, which can be applied to other biophysical systems of interest. The results presented in this study contribute significantly to understand GPCRs allosteric modulation and, hopefully, will encourage a more thorough exploration of the topic.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142711818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Crystal Structure of Human IgD-Fc Reveals Unexpected Differences With Other Antibody Isotypes.","authors":"Anna M Davies, Tam T T Bui, Raúl Pacheco-Gómez, Susan K Vester, Andrew J Beavil, Hannah J Gould, Brian J Sutton, James M McDonnell","doi":"10.1002/prot.26771","DOIUrl":"https://doi.org/10.1002/prot.26771","url":null,"abstract":"<p><p>Of the five human antibody isotypes, the function of IgD is the least well-understood, although various studies point to a role for IgD in mucosal immunity. IgD is also the least well structurally characterized isotype. Until recently, when crystal structures were reported for the IgD Fab, the only structural information available was a model for intact IgD based on solution scattering data. We now report the crystal structure of human IgD-Fc solved at 3.0 Å resolution. Although similar in overall architecture to other human isotypes, IgD-Fc displays markedly different orientations of the Cδ3 domains in the Cδ3 domain dimer and the lowest interface area of all the human isotypes. The nature of the residues that form the dimer interface also differs from those conserved in the other isotypes. By contrast, the interface between the Cδ2 and Cδ3 domains in each chain is the largest among the human isotypes. This interface is characterized by two binding pockets, not seen in other isotypes, and points to a potential role for the Cδ2/Cδ3 interface in stabilizing the IgD-Fc homodimer. We investigated the thermal stability of IgD-Fc, alone and in the context of an intact IgD antibody, and found that IgD-Fc unfolds in a single transition. Human IgD-Fc clearly has unique structural features not seen in the other human isotypes, and comparison with other mammalian IgD sequences suggests that these unique features might be widely conserved.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142711704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Alignments on the Accuracy of Protein Subcellular Localization Predictions.","authors":"Maryam Gillani, Gianluca Pollastri","doi":"10.1002/prot.26767","DOIUrl":"https://doi.org/10.1002/prot.26767","url":null,"abstract":"<p><p>Alignments in bioinformatics refer to the arrangement of sequences to identify regions of similarity that can indicate functional, structural, or evolutionary relationships. They are crucial for bioinformaticians as they enable accurate predictions and analyses in various applications, including protein subcellular localization. The predictive model used in this article is based on a deep - convolutional architecture. We tested configurations of Deep N-to-1 convolutional neural networks of various depths and widths during experimentation for the evaluation of better-performing values across a diverse set of eight classes. For without alignment assessment, sequences are encoded using one-hot encoding, converting each character into a numerical representation, which is straightforward for non-numerical data and useful for machine learning models. For with alignments assessment, multiple sequence alignments (MSAs) are created using PSI-BLAST, capturing evolutionary information by calculating frequencies of residues and gaps. The average difference in peak performance between models with alignments and without alignments is approximately 15.82%. The average difference in the highest accuracy achieved with alignments compared with without alignments is approximately 15.16%. Thus, extensive experimentation indicates that higher alignment accuracy implies a more reliable model and improved prediction accuracy, which can be trusted to deliver consistent performance across different layers and classes of subcellular localization predictions. This research provides valuable insights into prediction accuracies with and without alignments, offering bioinformaticians an effective tool for better understanding while potentially reducing the need for extensive experimental validations. The source code and datasets are available at http://distilldeep.ucd.ie/SCL8/.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142689808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the Structural Basis of Biased Agonism in the β₂-Adrenergic Receptor Through Molecular Dynamics Simulations.","authors":"Wojciech Plazinski, Aneta Archala, Krzysztof Jozwiak, Anita Plazinska","doi":"10.1002/prot.26766","DOIUrl":"https://doi.org/10.1002/prot.26766","url":null,"abstract":"<p><p>Biased agonism in G protein-coupled receptors is a phenomenon resulting in the selective activation of distinct intracellular signaling pathways by different agonists, which may exhibit bias toward either Gs, Gi, or arrestin-mediated pathways. This study investigates the structural basis of ligand-induced biased agonism within the context of the β₂-adrenergic receptor (β₂-AR). Atomistic molecular dynamics simulations were conducted for β₂-AR complexes with two stereoisomers of methoxynaphtyl fenoterol (MNFen), that is, compounds eliciting qualitatively different cellular responses. The simulations reveal distinct interaction patterns within the binding cavity, dependent on the stereoisomer. These changes propagate to the intracellular parts of the receptor, triggering various structural responses: the dynamic structure of the intracellular regions of the (R,R)-MNFen complex more closely resembles the \"G_s-compatible\" and \"β-arrestin-compatible\" conformation of β₂-AR, while both stereoisomers maintain structural responses equidistant from the inactive conformation. These findings are confirmed by independent coarse-grained simulations. In the context of deciphered molecular mechanisms, Trp313 plays a pivotal role, altering its orientation upon interactions with (R,R)-MNFen, along with the Lys305-Asp192 ionic bridge. This effect, accompanied by ligand interactions with residues on TM2, increases the strength of interactions within the extracellular region and the binding cavity, resulting in a slightly more open conformation and a minor (by ca. 0.2 nm) increase in the distance between the TM5-TM7, TM1-TM6, TM6-TM7, and TM1-TM5 pairs. On the other hand, an even slighter decrease in the distance between the TM1-TM4 and TM2-TM4 pairs is observed.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LGS-PPIS: A Local-Global Structural Information Aggregation Framework for Predicting Protein-Protein Interaction Sites.","authors":"Zhengli Zhai, Shiya Xu, Wenjian Ma, Niuwangjie Niu, Chunyu Qu, Chao Zong","doi":"10.1002/prot.26763","DOIUrl":"https://doi.org/10.1002/prot.26763","url":null,"abstract":"<p><p>Exploring protein-protein interaction sites (PPIS) is of significance to elucidating the intrinsic mechanisms of diverse biological processes. On this basis, recent studies have applied deep learning-based technologies to overcome the high cost of wet experiments for PPIS determination. However, the existing methods still suffer from two limitations that remain to be solved. Firstly, the process of feature aggregation in most methods only took into account node features, but ignored the complex edge features of the target residue to its neighbor residues, resulting in insufficient local feature extraction. Secondly, such feature aggregation was limited to aggregating spatially adjacent residues, and could not capture the \"remote\" residues that played a critical role in determining PPIS, which can be summed up as the lack of global feature at the residue level. To break the above limitations, a local-global structural information aggregation framework, LGS-PPIS, was proposed in this study, including two modules of edge-aware graph convolutional network (EA-GCN) and self-attention integrated with initial residual and identity mapping (SA-RIM), which achieved the aggregation of local and global information for PPIS prediction. Evaluation results of LGS-PPIS showed that the proposed method outperformed state-of-the-art deep learning methods on three widely used PPIS prediction benchmarks. Besides, the results of ablation experiments demonstrated that the local features from spatially adjacent residues and global features from \"remote\" residues separately captured by EA-GCN and SA-RIM could benefit the model performance. Among them, the former was shown to have a more significant role in the PPIS prediction.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142633086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Localized Amino Acid Enrichment Analysis as a Tool for Understanding Protein Extremophilicity.","authors":"Elliot Hill, Avery Hill, Elena Voisin, Amber Byrd, Allyn Schoeffler","doi":"10.1002/prot.26760","DOIUrl":"https://doi.org/10.1002/prot.26760","url":null,"abstract":"<p><p>Sequence conservation analyses offer us a powerful glimpse of natural selection at work. Standard tools for measuring sequence conservation report conservation as a function of a specific location in a multiple sequence alignment and have proven indispensable in identifying highly constrained features such as active site residues. The advent of large-scale genomic sequencing efforts allows researchers to expand this paradigm and investigate more nuanced relationships between sequence and function. Here, we present a simple tool (SWiLoDD: Sliding Window Localized Differentiation Detection) that allows researchers to analyze local, rather than site-specific, conservation using a sliding window approach. Our tool accepts multiple sequence alignments partitioned based on a biological differentiator and returns alignment position-based, localized differential enrichment metrics for amino acids of choice. We present two case studies of this analysis in action: local-but-diffuse glycine enrichments in the ATPase subunits of thermophilic and psychrophilic bacterial gyrase homologs, and ligand- and interface-specific amino acid enrichments in halophilic bacterial crotonyl-CoA carboxylases/reductases. Though we have described examples of extremophilic bacterial proteins in this study, our tool may be used to investigate any set of homologous sequences from which sub-groups can be meaningfully partitioned. Our results suggest that investigating differential localized conservation in partitioned MSAs will expand our understanding of how sequence conservation and protein function are connected.</p>","PeriodicalId":56271,"journal":{"name":"Proteins-Structure Function and Bioinformatics","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142606480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}