Immunodominant protein MIP_05962 from Mycobacterium indicus pranii displays chaperone activity.

Tuberculosis, a contagious disease of infectious origin is currently a major cause of deaths worldwide. Mycobacterium indicus pranii (MIP), a saprophytic non-pathogen and a potent immunomodulator is currently being investigated as an intervention against tuberculosis along with many other diseases with positive outcome. The apparent paradox of multiple chaperones in mycobacterial species and enigma about the cellular functions of the client proteins of these chaperones need to be explored. Chaperones are the known immunomodulators thus there is need to exploit the proteome of MIP for identification and characterization of putative chaperones. One of the immunogenic proteins, MIP_05962 is a member of HSP20 family due to presence of α-crystallin domain, and has amino acid similarity with M.leprae HSP18 protein. The diverse functions of M.leprae HSP18 in stress conditions implicate MIP_05962 as an important protein that needs to be explored. Biophysical and biochemical characterization of the said protein proved it to be a chaperone. The observations of aggregation prevention and refolding of substrate proteins in presence of MIP_05962 along with interaction with non-native proteins, surface hydrophobicity, formation of large oligomers, in-vivo thermal rescue of E.coli expressing MIP_05962, enhancing solubility of insoluble protein MalZ under in-vivo conditions and thermal stability and reversibility confirmed MIP_05962 as a molecular chaperone. This article is protected by copyright. All rights reserved.