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Functional characterization of a small heat shock protein from Mycobacterium leprae

Nirmala Lini1, Elengikal Abdul Azeez Rehna, Sugathan Shiburaj

  • 1Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Tamil Nadu, India. lininirmala@gmail.com

BMC Microbiology
|December 2, 2008
PubMed
Abstract

Insights

Mycobacterium leprae small heat shock protein (sHsp18) functions as a chaperone, preventing enzyme inactivation and forming complexes. This membrane-associated protein may contribute to M. leprae survival and virulence in leprosy patients.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Immunology

Background:

  • Small heat shock proteins (sHsps) are crucial for pathogen survival and virulence.
  • Mycobacterium leprae, the leprosy agent, is difficult to cultivate, necessitating heterologous expression for study.
  • Limited knowledge exists regarding the function of M. leprae sHsp18, a significant immunodominant antigen.

Purpose of the Study:

  • To clone and characterize the Mycobacterium leprae small heat shock protein (sHsp18).
  • To investigate the in vitro chaperone activity and cellular localization of sHsp18.

Main Methods:

  • Amplification and cloning of the M. leprae sHsp18 gene into E. coli.
  • Expression and purification of recombinant sHsp18.
  • In vitro assays to assess chaperone activity (e.g., enzyme protection) and protein complex formation.
  • Localization studies in E. coli.

Main Results:

  • The M. leprae sHsp18 gene was successfully cloned and expressed in E. coli.
  • A significant portion of the expressed sHsp18 localized to the outer membrane of E. coli.
  • Purified sHsp18 demonstrated efficient in vitro chaperone activity, protecting restriction enzymes from thermal inactivation.
  • sHsp18 was shown to interact physically with target proteins and form multimeric complexes.

Conclusions:

  • M. leprae sHsp18 functions as a molecular chaperone with properties similar to other sHsps.
  • The observed membrane association and chaperone activity suggest a role for sHsp18 in M. leprae virulence and survival within the host.

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