Biology subjects

Calligari, P.

Publications and source records attributed to Calligari, P..

3 recordsLinked to original sources

bioRxiv2025

GROMODEX: Optimisation of GROMACS Performance through a Design of Experiment Approach

We introduce GROMODEX, a novel tool designed to optimise GROMACS molecular dynamics (MD) simulations using a structured Design of Experiments (DoE) approach. GROMACS, though efficient, requires extensive tuning of parameters to perform optimally on different hardware and molecular systems. Manual tuning is tedious and prone to errors, especially for high-performance computing (HPC) environments. GROMODEX automates this process, systematically exploring performance parameters to find the best configurations for each system. By using statistical techniques, it evaluates multiple parameters simultaneously, optimising for CPU and GPU architectures, and reducing simulation times while ensuring efficient resource use. We evaluated GROMODEX on four computational platforms spanning a wide range of cost and hardware complexity using four molecular systems from the NVIDIA GROMACS benchmark suite. Quite surprisingly, our results show that the performance does not always correlate with the hardware complexity and cost in a system-dependent manner. Furthermore, a fine system-dependent tuning assures substantial performance gains and time reductions, highlighting GROMODEXs ability to improve the performance of MD simulations significantly.

biophysics↗

bioRxiv2020

Peptide-based Inhibitors of Protein-Protein Interactions of Src Homology 2 Domain-Containing Phosphatase 2

We developed a new class of inhibitors of protein-protein interactions of the SHP2 phosphatase, which is pivotal in multiple signaling pathways and a central target in the therapy of cancer and rare diseases. Currently available SHP2 inhibitors target the catalytic site or an allosteric pocket but lack specificity or are ineffective on disease-associated SHP2 mutants. Based on the consideration that pathogenic lesions cause signaling hyperactivation due to increased SHP2 association with cognate proteins, we developed peptide-based molecules with low nM affinity for the N-terminal Src homology domain of SHP2, good selectivity, stability to degradation and an affinity for pathogenic variants of SHP2 up to 20 times higher than for the wild-type protein. The best peptide reverted the effects of a pathogenic variant (D61G) in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool to investigate the role of protein-protein interactions in the function of SHP2.

biophysics↗

bioRxiv2020

Structural Determinants of Phosphopeptide Binding to the N-Terminal Src Homology 2 Domain of the SHP2 Phosphatase

SH2 domain-containing tyrosine phosphatase 2 (SHP2), encoded by PTPN11, plays a fundamental role in the modulation of several signaling pathways. Germline and somatic mutations in PTPN11 are associated with different rare diseases and hematologic malignancies, and recent studies have individuated SHP2 as a central node in oncogenesis and cancer drug resistance. SHP2 structure includes two Src homology 2 domains (N-SH2 and C-SH2) followed by a catalytic protein tyrosine phosphatase (PTP) domain. Under basal conditions, the N-SH2 domain blocks the active site, inhibiting phosphatase activity. Association of the N-SH2 domain with binding partners containing short amino acid motifs comprising a phosphotyrosine residue (pY) leads to N-SH2/PTP dissociation and SHP2 activation. Considering the relevance of SHP2 in signaling and disease and the central role of the N-SH2 domain in its allosteric regulation mechanism, we performed microsecond-long molecular dynamics simulations of the N-SH2 domain complexed to 12 different peptides, to define the structural and dynamical features determining the binding affinity and specificity of the domain. Phosphopeptide residues at position -2 to +5, with respect to pY, have significant interactions with the SH2 domain. In addition to the strong interaction of the pY residue with its conserved binding pocket, the complex is stabilized hydrophobically by insertion of residues +1, +3 and +5 in an apolar groove of the domain, and interaction of residue -2 with both the pY and a protein surface residue. Additional interactions are provided by hydrogen bonds formed by the backbone of residues -1, +1, +2 and +4. Finally, negatively charged residues at position +2 and +4 are involved in electrostatic interactions with two lysines (Lys89 and Lys91) specific of the SHP2 N-SH2 domain. Interestingly, the MD simulations illustrated a previously undescribed conformational flexibility of the domain, involving the core {beta}-sheet and the loop that closes the pY binding pocket.

biophysics↗