Single-Site Phosphorylation Elicits Structural, Dynamic, and Accessibility Changes in Proteins at both Proximal and Distal Regions to the Phosphosite.

Phosphorylation, a fundamental cellular mechanism, intricately regulates protein function and signaling pathways. Our study employs extensive computational analyses on a curated dataset of phosphorylated and unphosphorylated protein structures to explore the multifaceted impact of phosphorylation on protein conformation. Our findings reveal that phosphorylation induces not only local changes at the phosphorylation site but also extensive alterations in distant regions, showcasing its far-reaching influence on protein structure-dynamics. Using Normal Mode Analysis (NMA), we investigate changes in protein flexibility post-phosphorylation, highlighting an enhanced level of structural dynamism. Through in-depth case studies on Polyubiquitin-B and Glycogen Synthase Kinase-3 Beta, we elucidate how phosphorylation at distinct sites leads to variable structural and dynamic modifications, potentially dictating functional outcomes. While phosphorylation largely preserves residue motion correlation, it significantly disrupts low-frequency global modes, presenting a dualistic impact on protein dynamics. We also explore alterations in the total accessible surface area (ASA), emphasizing region-specific changes around phosphorylation sites. This study sheds light on phosphorylation-induced conformational changes, dynamic modulation, and surface accessibility alterations, contributing to a comprehensive understanding of cellular regulation and suggesting promising avenues for therapeutic interventions.