In silico characterization, homology modeling and structure-based functional annotation of Nile Tilapia (Oreochromis niloticus) Hsp70 and Hsc70 proteins

Abstract

BackgroundThe molecular chaperones known as heat shock proteins 70 (Hsp70) and heat shock cognate protein 70 (Hsc70) are vital for maintaining cellular integrity and controlling stress. MethodologyThe On-Hsp70 and On-Hsc70 proteins from Nile tilapia (Oreochromis niloticus) have been thoroughly examined in this study using in silico analysis, homology modeling, and functional annotation. Homology modeling was carried out using the SWISS- MODEL program, and the proposed model was assessed for its high reliability through analyses including ProSA, Verify 3D, PROVE, ERRAT, and Ramachandran plot. ResultsThe essential features of the On-Hsp70 and On-Hsc70 proteins encompass amino acid lengths (640 and 645), molecular weights (70,233.48 and 70,773.17 Da), theoretical isoelectric points (pI = 5.63 and 5.28), and the overall counts of negatively and positively charged residues (95 and 86; 95 and 81). Furthermore, the instability index (II) values were 35.27 (On-Hsp70) and 38.85 (On-Hsc70). Similarly, the aliphatic index (AI) exhibited high values for both proteins, reaching 84.58 (On-Hsp70) and 82.85 (On-Hsc70). On-Hsp70 and On-Hsc70 were both shown to contain an MreB/Mbl domain. DiscussionThe authors found that On-Hsp70 and On-Hsc70 share key characteristics, including an acidic nature, high stability, and conserved domains. Protein-protein interaction analysis identified the co-chaperone Stip1 as a primary functional partner. Comparative modeling yielded highly reliable 3D models, revealing structural similarity to known proteins and predicted binding sites. Furthermore, the primary subcellular localization of both proteins is the cytoplasm. Functional analysis predicted an AMP-PNP binding site for On-Hsp70 and ATP binding site for On-Hsc70. ConclusionThe discoveries deepen our understanding of Hsc70 and Hsp70 in Nile tilapia, highlighting their importance in fish physiology and positioning them as crucial study topics moving forward. This study adds to our understanding of the actions of these proteins in cellular processes and stress responses, which could impact fish health and resilience.