scholarly journals α-Helix stabilization by co-operative side chain charge-reinforced interactions to phosphoserine in a basic kinase-substrate motif

2021 ◽  
Author(s):  
Matthew Batchelor ◽  
Robert S Dawber ◽  
Andrew J Wilson ◽  
Richard Bayliss
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Side Chain ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Kinase Substrate ◽  
Human Proteins ◽  
Recognition Motifs ◽  
Α Helix ◽  
General Method

How cellular functions are regulated through protein phosphorylation events that promote or inhibit protein-protein interactions (PPIs) is key to understanding regulatory molecular mechanisms. Whilst phosphorylation can orthosterically or allosterically influence protein recognition, phospho-driven changes in the conformation of recognition motifs are less well explored. We recently discovered that clathrin heavy chain recognises phosphorylated TACC3 through a helical motif that, in the unphosphorylated protein, is disordered. However, it was unclear whether and how phosphorylation could stabilize a helix in a broader context. In the current manuscript, we address this challenge using poly-Ala based model peptides and a suite of circular dichroism and nuclear magnetic resonance spectroscopies. We show that phosphorylation of a Ser residue stabilizes the α-helix in the context of an Arg(i - 3)pSeri Lys(i + 4) triad through charge-reinforced side chain interactions with positive co-operativity, whilst phosphorylation of Thr induces an opposing response. This is significant as it may represent a general method for control of PPIs by phosphorylation; basic kinase-substrate motifs are common with 55 human protein kinases recognising an Arg at a position -3 from the phosphorylated Ser, whilst the Arg(i - 3)pSeri Lys(i + 4) is a motif found in over 2000 human proteins.

α-Helix mimetics as inhibitors of protein–protein interactions

2008 ◽  
Vol 36 (6) ◽  
pp. 1414-1417 ◽  
Author(s):  
Ishu Saraogi ◽  
Andrew D. Hamilton
Keyword(s):  
Protein Interactions ◽  
First Generation ◽  
Side Chain ◽  
Protein Protein Interactions ◽  
Substitution Pattern ◽  
Pathological Conditions ◽  
Synthetic Accessibility ◽  
Helix Mimetics ◽  
Viable Approach ◽  
Α Helix

The inhibition of protein–protein interactions using small molecules is a viable approach for the treatment of a range of pathological conditions that result from a malfunctioning of these interactions. Our strategy for the design of such agents involves the mimicry of side-chain residues on one face of the α-helix; these residues frequently play a key role in mediating protein–protein interactions. The first-generation terphenyl scaffold, with a 3,2′,2″-substitution pattern, is able to successfully mimic key helix residues and disrupt therapeutically relevant interactions, including the Bcl-XL–Bak and the p53–hDM2 (human double minute 2) interactions that are implicated in cancer. The second- and third-generation scaffolds have resulted in greater synthetic accessibility and more drug-like character in these molecules.

scholarly journals Structural basis for the interaction of SARS-CoV-2 virulence factor nsp1 with Pol α - Primase

2021 ◽  
Author(s):  
Mairi L Kilkenny ◽  
Charlotte E Veale ◽  
Amir Guppy ◽  
Steven W Hardwick ◽  
Dimitri Y Chirgadze ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Structural Basis ◽  
Structural Protein ◽  
Protein Protein Interactions ◽  
Major Virulence Factor ◽  
Biochemical Characterisation ◽  
Human Proteins ◽  
Primase Complex

The molecular mechanisms that drive the infection by the SARS-CoV-2 coronavirus, the causative agent of the COVID-19 (Coronavirus disease-2019) pandemic, are under intense current scrutiny, to understand how the virus operates and to uncover ways in which the disease can be prevented or alleviated. Recent cell-based analyses of SARS-CoV-2 protein - protein interactions have mapped the human proteins targeted by the virus. The DNA polymerase α - primase complex or primosome, responsible for initiating DNA synthesis in genomic duplication, was identified as a target of nsp1 (non structural protein 1), a major virulence factor in the SARS-CoV-2 infection. Here, we report the biochemical characterisation of the interaction between nsp1 and the primosome and the cryoEM structure of the primosome - nsp1 complex. Our data provide a structural basis for the reported interaction between the primosome and nsp1. They suggest that Pol α - primase plays a part in the immune response to the viral infection, and that its targeting by SARS-CoV-2 aims to interfere with such function.

scholarly journals Towards a structurally resolved human protein interaction network

2021 ◽  
Author(s):  
David F Burke ◽  
Patrick Bryant ◽  
Inigo Barrio-Hernandez ◽  
Danish Memon ◽  
Gabriele Pozzati ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Interaction Network ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Human Interactions ◽  
Pathogenic Variants ◽  
Binary Complexes

All cellular functions are governed by complex molecular machines that assemble through protein-protein interactions. Their atomic details are critical to the study of their molecular mechanisms but fewer than 5% of hundreds of thousands of human interactions have been structurally characterized. Here, we test the potential and limitations of recent progress in deep-learning methods using AlphaFold2 to predict structures for 65,484 human interactions. We show that higher confidence models are enriched in interactions supported by affinity or structure based methods and can be orthogonally confirmed by spatial constraints defined by cross-link data. We identify 3,137 high confidence models, of which 1,371 have no homology to a known structure, from which we identify interface residues harbouring disease mutations, suggesting potential mechanisms for pathogenic variants. We find groups of interface phosphorylation sites that show patterns of co-regulation across conditions, suggestive of coordinated tuning of multiple interactions as signalling responses. Finally, we provide examples of how the predicted binary complexes can be used to build larger assemblies. Accurate prediction of protein complexes promises to greatly expand our understanding of the atomic details of human cell biology in health and disease.

Using halo (het) arylboronic species to achieve synthesis of foldamers as protein–protein interaction disruptors

2012 ◽  
Vol 84 (11) ◽  
pp. 2467-2478 ◽  
Author(s):  
Anne Sophie Voisin-Chiret ◽  
Sylvain Rault
Keyword(s):  
Protein Interactions ◽  
Cell Biology ◽  
First Generation ◽  
In Silico Analysis ◽  
Side Chain ◽  
Protein Protein Interactions ◽  
Protein Protein Interaction ◽  
Common Motif ◽  
Difficult Procedure ◽  
Α Helix

Protein–protein interactions (PPIs) play a central role in all biological processes and have been the focus of intense investigations from structural molecular biology to cell biology for the majority of the last two decades and, more recently, are emerging as important targets for pharmaceuticals. A common motif found at the interface of PPIs is the α-helix, and apart from the peptidic structures, numerous nonpeptidic small molecules have been developed to mimic α-helices. The first-generation terphenyl scaffold is able to successfully mimic key helix residues and disrupt relevant interactions, including Bcl-xL-Bak interactions that are implicated in apoptosis mechanism. These scaffolds were designed and evaluated in silico. Analysis revealed that substituents on aromatic scaffolds can efficiently mimic side-chain surfaces. Unfortunately, the literature describes a long and difficult procedure to access these aromatic-based scaffolds. The search for new simpler methodology is the aim of the research of our medicinal chemistry team. On the basis of structural requirements, we developed a program concerning the synthesis of new oligo(het)aryl scaffolds produced by iterative couplings of boronic species (garlanding) in which substituents on rings project functionality in spatial orientations that mimic residues of an α-helix.

scholarly journals Towards a structurally resolved human protein interaction network

2021 ◽  
Author(s):  
Arne Elofsson ◽  
David Burke ◽  
Patrick Bryant ◽  
Inigo Barrio-Hernandez ◽  
Danish Memon ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Interaction Network ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Human Interactions ◽  
Pathogenic Variants ◽  
Binary Complexes

Abstract All cellular functions are governed by complex molecular machines that assemble through protein-protein interactions. Their atomic details are critical to the study of their molecular mechanisms but fewer than 5% of hundreds of thousands of human interactions have been structurally characterized. Here, we test the potential and limitations of recent progress in deep-learning methods using AlphaFold2 to predict structures for 65,484 human interactions. We show that higher confidence models are enriched in interactions supported by affinity or structure based methods and can be orthogonally confirmed by spatial constraints defined by cross-link data. We identify 3,137 high confidence models, of which 1,371 have no homology to a known structure, from which we identify interface residues harbouring disease mutations, suggesting potential mechanisms for pathogenic variants. We find groups of interface phosphorylation sites that show patterns of co-regulation across conditions, suggestive of coordinated tuning of multiple interactions as signalling responses. Finally, we provide examples of how the predicted binary complexes can be used to build larger assemblies. Accurate prediction of protein complexes promises to greatly expand our understanding of the atomic details of human cell biology in health and disease.

scholarly journals Peptide-based inhibitors of protein–protein interactions: biophysical, structural and cellular consequences of introducing a constraint

2021 ◽  
Author(s):  
Hongshuang Wang ◽  
Robert S. Dawber ◽  
Peiyu Zhang ◽  
Martin Walko ◽  
Andrew J. Wilson ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Α Helix ◽  
Cellular Behaviour

This review summarizes the influence of inserting constraints on biophysical, conformational, structural and cellular behaviour for peptides targeting α-helix mediated protein–protein interactions.

Structure, Function, Involvement in Diseases and Targeting of 14-3-3 Proteins: An Update

2018 ◽  
Vol 25 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Ylenia Cau ◽  
Daniela Valensin ◽  
Mattia Mori ◽  
Sara Draghi ◽  
Maurizio Botta
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Cellular Processes ◽  
Protein Partners ◽  
High Sequence Homology ◽  
Small Molecule Modulators

14-3-3 is a class of proteins able to interact with a multitude of targets by establishing protein-protein interactions (PPIs). They are usually found in all eukaryotes with a conserved secondary structure and high sequence homology among species. 14-3-3 proteins are involved in many physiological and pathological cellular processes either by triggering or interfering with the activity of specific protein partners. In the last years, the scientific community has collected many evidences on the role played by seven human 14-3-3 isoforms in cancer or neurodegenerative diseases. Indeed, these proteins regulate the molecular mechanisms associated to these diseases by interacting with (i) oncogenic and (ii) pro-apoptotic proteins and (iii) with proteins involved in Parkinson and Alzheimer diseases. The discovery of small molecule modulators of 14-3-3 PPIs could facilitate complete understanding of the physiological role of these proteins, and might offer valuable therapeutic approaches for these critical pathological states.

scholarly journals Interactions between Integrase and Excisionase in the Phage Lambda Excisive Nucleoprotein Complex

2002 ◽  
Vol 184 (18) ◽  
pp. 5200-5203 ◽  
Author(s):  
Eun Hee Cho ◽  
Richard I. Gumport ◽  
Jeffrey F. Gardner
Keyword(s):  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Mobility Shift ◽  
Host Chromosome ◽  
Amino Terminal ◽  
Nucleoprotein Complex ◽  
Carboxyl Terminal ◽  
Α Helix ◽  
Gel Mobility Shift ◽  
Amino Terminal Domain

ABSTRACT Bacteriophage lambda site-specific recombination comprises two overall reactions, integration into and excision from the host chromosome. Lambda integrase (Int) carries out both reactions. During excision, excisionase (Xis) helps Int to bind DNA and introduces a bend in the DNA that facilitates formation of the proper excisive nucleoprotein complex. The carboxyl-terminal α-helix of Xis is thought to interact with Int through direct protein-protein interactions. In this study, we used gel mobility shift assays to show that the amino-terminal domain of Int maintained cooperative interactions with Xis. This finding indicates that the amino-terminal arm-type DNA binding domain of Int interacts with Xis.

Quantitative analysis of the interactions between HIV-1 integrase and retroviral reverse transcriptases

2008 ◽  
Vol 412 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Alon Herschhorn ◽  
Iris Oz-Gleenberg ◽  
Amnon Hizi
Keyword(s):  
Conformational Changes ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Reaction Model ◽  
Protein Protein Interactions ◽  
Common Site ◽  
Leukaemia Virus ◽  
Reverse Transcriptases ◽  
Interaction Kinetics ◽  
Hiv 1

The RT (reverse transcriptase) of HIV-1 interacts with HIV-1 IN (integrase) and inhibits its enzymatic activities. However, the molecular mechanisms underling these interactions are not well understood. In order to study these mechanisms, we have analysed the interactions of HIV-1 IN with HIV-1 RT and with two other related RTs: those of HIV-2 and MLV (murine-leukaemia virus). All three RTs inhibited HIV-1 IN, albeit to a different extent, suggesting a common site of binding that could be slightly modified for each one of the studied RTs. Using surface plasmon resonance technology, which monitors direct protein–protein interactions, we performed kinetic analyses of the binding of HIV-1 IN to these three RTs and observed interesting binding patterns. The interaction of HIV-1 RT with HIV-1 IN was unique and followed a two-state reaction model. According to this model, the initial IN–RT complex formation was followed by a conformational change in the complex that led to an elevation of the total affinity between these two proteins. In contrast, HIV-2 and MLV RTs interacted with IN in a simple bi-molecular manner, without any apparent secondary conformational changes. Interestingly, HIV-1 and HIV-2 RTs were the most efficient inhibitors of HIV-1 IN activity, whereas HIV-1 and MLV RTs showed the highest affinity towards HIV-1 IN. These modes of direct protein interactions, along with the apparent rate constants calculated and the correlations of the interaction kinetics with the capacity of the RTs to inhibit IN activities, are all discussed.

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