Structural and Functional Impacts of Extended N-Terminal End of the Small Heat Shock Protein Tpv HSP 14.3

2024-04-01
Abstract: Small heat shock proteins (sHSPs) are composed of the α-crystallin domain, which is highly conserved, and variable N-terminal and C-terminal domains. In contrast to the α-crystallin domain, structures of the flanking N- and C-terminal domains are poorly defined. The N-terminal domain is the most divergent region in sequence and length among small heat shock proteins. In this study, to provide further insight into the importance of N-terminal tags in the chaperone function of small heat shock proteins, two variants of Tpv HSP 14.3 containing polyhistidine tags (11-aa and 26-aa in length) in the proximal part of their N-termini were used. These variants were generated by expressing the cloned Tpv HSP 14.3 gene in Escherichia coli using the expression vectors pQE-31 and TAGZyme pQE-2. The His-tagged recombinant proteins were purified by affinity chromatography. The effects of poly-His tags on chaperone activity of the Tpv HSP 14.3 were evaluated using pig heart citrate synthase as the model substrate. The results showed that Tpv HSP 14.3 variants with N-terminal tags were more effective chaperones than the one without tag. In addition, the alterations in intrinsically disordered states of N-termini were analyzed by means of the PONDR predictor. The results indicated that the disordered nature of the fused tags and additional hydrophobic residues they contributed to the N terminus may increase the capacity of Tpv HSP 14.3 to interact with its substrate protein and thereby improve its chaperone activity.
Applied Biochemistry and Microbiology
Citation Formats
S. Zabci and S. Kocabıyık, “Structural and Functional Impacts of Extended N-Terminal End of the Small Heat Shock Protein Tpv HSP 14.3,” Applied Biochemistry and Microbiology, vol. 60, no. 2, pp. 287–293, 2024, Accessed: 00, 2024. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85190896324&origin=inward.