Biology subjects

Peterfia, B.

Publications and source records attributed to Peterfia, B..

4 recordsLinked to original sources

bioRxiv2025

Redistribution of sidechain-sidechain interactions govern ligand-specific binding affinity changes in missense Shank1 PDZ mutants

Shank proteins represent a family of abundant scaffolds in the postsynaptic density. Their dysfunctions had been identified as possible causes behind autism spectrum disorders and various types of cancer. The remarkably promiscuous PDZ domain of the Shank family is highly conserved through isoforms, and contains a unique dynamic segment, the {beta}2-{beta}3 loop, located close to the binding site. We used the Shank1 PDZ as a model system to analyze the perturbing effects of five disease-associated missense mutations on the binding of different partner peptides. Using experimental methods and molecular dynamics simulations, we characterized the interactions in detail, focusing on their dynamic aspect. While the investigated variants in general weaken most interactions, the R736Q variant, unique in having increased thermal stability, also binds the GKAP peptide with higher affinity than the wild type. Overall, our results show that the perturbing effect of mutations is highly partner-specific and depends on the dynamic rearrangements of both uniformly occurring and ligand-specific residue-residue interactions.

molecular biology↗

bioRxiv2025

Structural modelling and dynamics of the full-length Homer1 multimer

Abstract/SummaryHomer proteins are modular scaffold molecules that constitute an integral part of the protein network within the postsynaptic density. Full-length Homer1 forms a large homotetramer via a long coiled coil region, and can interact with proline-rich target sequences with its globular EVH1 domain. Here we report an atomistic model of the full-length Homer1 tetramer along with the NMR solution structure of its EVH1 domain. Compared to the already available EVH1 structures, our NMR ensemble exhibits subtle differences, mostly in and around its partner binding region, suggesting the presence of ligand-induced conformational transitions. Molecular dynamics simulations of the long coiled coil reveal distinct regions with different stability and flexibility, with the N-terminal part of the coiled coil exhibiting the largest motions. Interestingly, this segment is highly conserved, pointing to the functional relevance of the observed dynamical features. Our results indicate previously unexplored aspects of the flexibility of the full-length Homer1 tetramer that might contribute to the dynamic rearrangements of the postsynaptic protein network linked to its functional transitions.

molecular biology↗

bioRxiv2024

Residual flexibility in the topologically constrained multivalent complex between the GKAP scaffold and LC8 hub proteins

Guanylate kinase-associated protein (GKAP) is a large postsynaptic scaffold protein bearing two closely spaced noncanonical binding sites for the bivalent dynein light chain LC8 hub protein. This might allow the formation of heterogeneous complexes with different sizes and topologies. Here, we show that a well-defined hexameric complex is formed, composed of 2 GKAP molecules and 2 LC8 dimers. Using NMR spectroscopy, we demonstrate that the LC8-binding segment of GKAP is intrinsically disordered and the flexibility of the linker region is largely retained even in the complex form. Molecular dynamics calculations suggest that besides the tightly bound residues, the hexamer also exhibits several dynamically interchanging interactions. The flanking regions of the two binding sites on GKAP exhibit different interaction patterns, hinting at additional contacts that might explain the fixed stoichiometry of the assembly. Our results demonstrate that constrained stoichiometry can coexist with substantial flexibility in a multivalent system.

molecular biology↗

bioRxiv2018

Multiple polyvalency provided by intrinsically disordered segments is a key feature of postsynaptic scaffold proteins

The human postsynaptic density is an elaborate network comprising thousands of proteins, playing a vital role in the molecular events of learning and the formation of memory. Despite our growing knowledge of specific proteins and their interactions, atomic-level details of their full three-dimensional structure and their rearrangements are mostly elusive. Advancements in structural bioinformatics enabled us to depict the characteristic features of proteins involved in different processes aiding neurotransmission. We show that postsynaptic protein-protein interactions are mediated through the delicate balance of intrinsically disordered regions and folded domains, and this duality is also imprinted in the amino acid sequence. We introduce Diversity of Potential Interactions (DPI), a structure and regulation based descriptor to assess the diversity of interactions. Our approach reveals that the postsynaptic proteome has its own characteristic features and these properties reliably discriminate them from other proteins of the human proteome. Our results suggest that postsynaptic proteins are especially susceptible to forming diverse interactions with each other, which might be key in the reorganization of the PSD in molecular processes related to learning and memory.

bioinformatics↗