Molecular Biotechnology, 2024 (SCI-Expanded)
The highly conserved alpha crystallin domain of the small heat shock proteins is essential for dimerization and also implicated in substrate interaction. In this study, we designed four novel mini-peptides from alpha crystallin domain of archaeal Small Heat Shock Protein Tpv HSP 14.3. Among the peptide designs, the mini-peptides 38SDLVLEAEMAGFDKKNIKVS57 and 40LVLEAEMAGFD50 overlapped to the sequences of β3-β4 region. The other two peptides 77YIDQRVDKVYKVVKLPVE94 and 107GILTVRMK114 correspond to β6-β7 region and β9, respectively. Functional activity of the peptides was evaluated by monitoring heat-induced aggregation of the model substrates alcohol dehydrogenase at 43 °C and citrate synthase at 45 °C. Our results showed that the (38–57) and the (77–94) fragments exhibited chaperone activity with both of the substrate proteins. The (40–50) fragment while exhibiting a noticeable protective effect (> 90%) when tested with citrate synthase showed an anti-chaperone property toward alcohol dehydrogenase. Unlike the (40–50) fragment, the (107–114) fragment did not show any chaperone activity with citrate synthase but exhibited the highest chaperone efficiency among four mini-peptides with alcohol dehydrogenase. The selectivity of the (40–50) and the (107–114) fragments in targeting the client proteins is most likely dependent on their surface hydrophobicity and/or charge as revealed by the sequence and exposed surface analyses.