scholarly journals Structural properties and peptide ligand binding of the capsid homology domains of human Arc

2020 ◽  
Author(s):  
Erik I. Hallin ◽  
Clive R. Bramham ◽  
Petri Kursula

AbstractThe activity-regulated cytoskeleton-associated protein (Arc) is important for synaptic scaling and the normal function of the brain. Arc interacts with many neuronal postsynaptic proteins, but the mechanistic details of its function have not been fully established. The C-terminal domain of Arc consists of tandem domains, termed the N- and C-lobe. The N-lobe harbours a peptide binding site, able to bind to multiple targets. By measuring the affinity of various peptides towards human Arc, we have refined the specificity determinants of this site. We found two sites in the GKAP repeat region that may bind to Arc and confirmed these interactions by X-ray crystallography. Comparison of the crystal structures of three human Arc-peptide complexes identifies 3 conserved C-H...π interactions at the binding cavity, which explain the sequence specificity of short linear motif binding by Arc. By analysing the structures, we further characterise central residues of the Arc lobe fold, show the effects of peptide binding on protein dynamics, and identify acyl carrier proteins as structures similar to the Arc lobes. We hypothesise that Arc may affect protein-protein interactions and phase separation at the postsynaptic density, affecting protein turnover and re-modelling of the synapse.

2020 ◽  
Vol 20 (10) ◽  
pp. 855-882
Author(s):  
Olivia Slater ◽  
Bethany Miller ◽  
Maria Kontoyianni

Drug discovery has focused on the paradigm “one drug, one target” for a long time. However, small molecules can act at multiple macromolecular targets, which serves as the basis for drug repurposing. In an effort to expand the target space, and given advances in X-ray crystallography, protein-protein interactions have become an emerging focus area of drug discovery enterprises. Proteins interact with other biomolecules and it is this intricate network of interactions that determines the behavior of the system and its biological processes. In this review, we briefly discuss networks in disease, followed by computational methods for protein-protein complex prediction. Computational methodologies and techniques employed towards objectives such as protein-protein docking, protein-protein interactions, and interface predictions are described extensively. Docking aims at producing a complex between proteins, while interface predictions identify a subset of residues on one protein that could interact with a partner, and protein-protein interaction sites address whether two proteins interact. In addition, approaches to predict hot spots and binding sites are presented along with a representative example of our internal project on the chemokine CXC receptor 3 B-isoform and predictive modeling with IP10 and PF4.


The Copley Medal is awarded to Professor Dorothy M. C. Hodgkin, O. M., F. R. S. Professor Dorothy Hodgkin is distinguished for her research on the structure of complex organic molecules by the method of X-ray crystallography. She was among the first to appreciate the importance of heavy-atom phase-determining methods and these she used to effect the first complete determination of the stereochemistry of a sterol derivative in her analysis of cholesteryl iodide. The same powerful method of analysis and in particular her extraordinary gift of being able to interpret correctly the complex, partially resolved and often misleading electron density patterns that are first obtained, have been responsible for her success in elucidating the structures of many other important natural products, especially penicillin and vitamin B 12 . This last is by far the most beautiful and complex analysis which has yet been completed in this field and it is of fundamental importance to chemical science. In recent years Professor Hodgkin’s main interest has been devoted to the structure of insulin, on which she has been working on and off since 1935. Carried out with characteristic precision, this work has become a mine of stereochemical information relating to contacts between polypeptide chains and is of great significance for our interpretation of protein-protein interactions.


2009 ◽  
Vol 390 (8) ◽  
Author(s):  
Reinhard Krämer ◽  
Christine Ziegler

Abstract Activation of the osmoregulated trimeric betaine transporter BetP from Corynebacterium glutamicum was shown to depend mainly on the correct folding and integrity of its 55 amino acid long, partly α-helical C-terminal domain. Reorientation of the three C-terminal domains in the BetP trimer indicates different lipid-protein and protein-protein interactions of the C-terminal domain during osmoregulation. A regulation mechanism is suggested where this domain switches the transporter from the inactive to the active state. Interpretation of recently obtained electron and X-ray crystallography data of BetP led to a structure-function based model of C-terminal molecular switching involved in osmoregulation.


Biochemistry ◽  
2005 ◽  
Vol 44 (45) ◽  
pp. 14932-14947 ◽  
Author(s):  
Michael C. Sweeney ◽  
Anne-Sophie Wavreille ◽  
Junguk Park ◽  
Jonathan P. Butchar ◽  
Susheela Tridandapani ◽  
...  

Author(s):  
Fatma-Elzahraa Eid ◽  
Haitham Elmarakeby ◽  
Yujia Alina Chan ◽  
Nadine Fornelos Martins ◽  
Mahmoud ElHefnawi ◽  
...  

AbstractRepresentational biases that are common in biological data can inflate prediction performance and confound our understanding of how and what machine learning (ML) models learn from large complicated datasets. However, auditing for these biases is not a common practice in ML in the life sciences. Here, we devise a systematic auditing framework and harness it to audit three different ML applications of significant therapeutic interest: prediction frameworks of protein-protein interactions, drug-target bioactivity, and MHC-peptide binding. Through this, we identify unrecognized biases that hinder the ML process and result in low model generalizability. Ultimately, we show that, when there is insufficient signal in the training data, ML models are likely to learn primarily from representational biases.


2012 ◽  
Vol 45 (4) ◽  
pp. 383-426 ◽  
Author(s):  
Anja Winter ◽  
Alicia P. Higueruelo ◽  
May Marsh ◽  
Anna Sigurdardottir ◽  
Will R Pitt ◽  
...  

AbstractDrug discovery has classically targeted the active sites of enzymes or ligand-binding sites of receptors and ion channels. In an attempt to improve selectivity of drug candidates, modulation of protein–protein interfaces (PPIs) of multiprotein complexes that mediate conformation or colocation of components of cell-regulatory pathways has become a focus of interest. However, PPIs in multiprotein systems continue to pose significant challenges, as they are generally large, flat and poor in distinguishing features, making the design of small molecule antagonists a difficult task. Nevertheless, encouragement has come from the recognition that a few amino acids – so-called hotspots – may contribute the majority of interaction-free energy. The challenges posed by protein–protein interactions have led to a wellspring of creative approaches, including proteomimetics, stapled α-helical peptides and a plethora of antibody inspired molecular designs. Here, we review a more generic approach: fragment-based drug discovery. Fragments allow novel areas of chemical space to be explored more efficiently, but the initial hits have low affinity. This means that they will not normally disrupt PPIs, unless they are tethered, an approach that has been pioneered by Wells and co-workers. An alternative fragment-based approach is to stabilise the uncomplexed components of the multiprotein system in solution and employ conventional fragment-based screening. Here, we describe the current knowledge of the structures and properties of protein–protein interactions and the small molecules that can modulate them. We then describe the use of sensitive biophysical methods – nuclear magnetic resonance, X-ray crystallography, surface plasmon resonance, differential scanning fluorimetry or isothermal calorimetry – to screen and validate fragment binding. Fragment hits can subsequently be evolved into larger molecules with higher affinity and potency. These may provide new leads for drug candidates that target protein–protein interactions and have therapeutic value.


The Copley Medal is awarded to Professor Dorothy M. C. Hodgkin, O. M., F. R. S. Professor Dorothy Hodgkin is distinguished for her research on the structure of complex organic molecules by the method of X-ray crystallography. She was among the first to appreciate the importance of heavy-atom phase-determining methods and these she used to effect the first complete determination of the stereochemistry of a sterol derivative in her analysis of cholesteryl iodide. The same powerful method of analysis and in particular her extraordinary gift of being able to interpret correctly the complex, partially resolved and often misleading electron density patterns that are first obtained, have been responsible for her success in elucidating the structures of many other important natural products, especially penicillin and vitamin B 12 . This last is by far the most beautiful and complex analysis which has yet been completed in this field and it is of fundamental importance to chemical science. In recent years Professor Hodgkin’s main interest has been devoted to the structure of insulin, on which she has been working on and off since 1935. Carried out with characteristic precision, this work has become a mine of stereochemical information relating to contacts between polypeptide chains and is of great significance for our interpretation of protein-protein interactions.


2018 ◽  
Vol 46 (14) ◽  
pp. 7469-7470 ◽  
Author(s):  
Moran Shalev ◽  
Rona Aviram ◽  
Yaarit Adamovich ◽  
Judith Kraut-Cohen ◽  
Tal Shamia ◽  
...  

2020 ◽  
Vol 36 (8) ◽  
pp. 2458-2465 ◽  
Author(s):  
Isak Johansson-Åkhe ◽  
Claudio Mirabello ◽  
Björn Wallner

Abstract Motivation Interactions between proteins and peptides or peptide-like intrinsically disordered regions are involved in many important biological processes, such as gene expression and cell life-cycle regulation. Experimentally determining the structure of such interactions is time-consuming and difficult because of the inherent flexibility of the peptide ligand. Although several prediction-methods exist, most are limited in performance or availability. Results InterPep2 is a freely available method for predicting the structure of peptide–protein interactions. Improved performance is obtained by using templates from both peptide–protein and regular protein–protein interactions, and by a random forest trained to predict the DockQ-score for a given template using sequence and structural features. When tested on 252 bound peptide–protein complexes from structures deposited after the complexes used in the construction of the training and templates sets of InterPep2, InterPep2-Refined correctly positioned 67 peptides within 4.0 Å LRMSD among top10, similar to another state-of-the-art template-based method which positioned 54 peptides correctly. However, InterPep2 displays a superior ability to evaluate the quality of its own predictions. On a previously established set of 27 non-redundant unbound-to-bound peptide–protein complexes, InterPep2 performs on-par with leading methods. The extended InterPep2-Refined protocol managed to correctly model 15 of these complexes within 4.0 Å LRMSD among top10, without using templates from homologs. In addition, combining the template-based predictions from InterPep2 with ab initio predictions from PIPER-FlexPepDock resulted in 22% more near-native predictions compared to the best single method (22 versus 18). Availability and implementation The program is available from: http://wallnerlab.org/InterPep2. Supplementary information Supplementary data are available at Bioinformatics online.


2021 ◽  
Vol 9 (7) ◽  
pp. 1509
Author(s):  
Ilena Benoit ◽  
Signy Brownell ◽  
Renée N. Douville

Integrase (IN) enzymes are found in all retroviruses and are crucial in the retroviral integration process. Many studies have revealed how exogenous IN enzymes, such as the human immunodeficiency virus (HIV) IN, contribute to altered cellular function. However, the same consideration has not been given to viral IN originating from symbionts within our own DNA. Endogenous retrovirus-K (ERVK) is pathologically associated with neurological and inflammatory diseases along with several cancers. The ERVK IN interactome is unknown, and the question of how conserved the ERVK IN protein–protein interaction motifs are as compared to other retroviral integrases is addressed in this paper. The ERVK IN protein sequence was analyzed using the Eukaryotic Linear Motif (ELM) database, and the results are compared to ELMs of other betaretroviral INs and similar eukaryotic INs. A list of putative ERVK IN cellular protein interactors was curated from the ELM list and submitted for STRING analysis to generate an ERVK IN interactome. KEGG analysis was used to identify key pathways potentially influenced by ERVK IN. It was determined that the ERVK IN potentially interacts with cellular proteins involved in the DNA damage response (DDR), cell cycle, immunity, inflammation, cell signaling, selective autophagy, and intracellular trafficking. The most prominent pathway identified was viral carcinogenesis, in addition to select cancers, neurological diseases, and diabetic complications. This potentiates the role of ERVK IN in these pathologies via protein–protein interactions facilitating alterations in key disease pathways.


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