Stabilization of the primary sigma factor of Staphylococcus aureus by core RNA polymerase

BMB Reports

Rajkrishna Mondal^1¹  Amitava Bandhu^1²  Palas K Chanda^1³  Tridib Ganguly^2⁴ 

[1] Department of Biochemistry, Bose Institute^1;Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, USA^4;School of Biotechnology and Life Sciences, Haldia Institute of Technology, Haldia, India^3;School of Life Sciences, IISER, Kolkata^2

关键词: Primary sigma factor;   

DOI  :  

学科分类：生物化学/生物物理

来源: Korean Society for Biochemistry and Molecular Biology

【 摘 要 】

The primary sigma factor (sigma(A)) of Staphylococcus aureus, a potential drug target, was little investigated at the structural level. Using an N-terminal histidine-tagged sigma(A) (His-sigma(A)), here we have demonstrated that it exits as a monomer in solution, possesses multiple domains, harbors primarily alpha-helix and efficiently binds to a S. aureus promoter DNA in the presence of core RNA polymerase. While both N- and C-terminal ends of His- sigma(A) are flexible in nature, two Trp residues in its DNA binding region are buried. Upon increasing the incubation temperature from 25 degrees to 40 degrees C, 60% of the input His-sigma(A) was cleaved by thermolysin. Aggregation of His-sigma(A) was also initiated rapidly at 45( degrees )C. From the equilibrium unfolding experiment, the Gibbs free energy of stabilization of His-sigma(A) was estimated to be +0.70 kcal mol(-1). The data together suggest that primary sigma factor of S. aureus is an unstable protein. Core RNA polymerase however stabilized sigma(A) appreciably.

【 授权许可】

Unknown