X-ray structure of peptidyl-prolyl cis–trans isomerase A from Mycobacterium tuberculosis

Abstract

Peptidyl-prolyl cis–trans isomerases (EC 5.2.1.8) catalyse the interconversion of cis and trans peptide bonds and are therefore considered to be important for protein folding. They are also thought to participate in processes such as signalling, cell surface recognition, chaperoning and heatshock response. Here we report the soluble expression of recombinant Mycobacterium tuberculosis peptidyl-prolyl cis–trans isomerase PpiA in Escherichia coli, together with an investigation of its structure and biochemical properties. The protein was shown to be active in a spectrophotometric assay, with an estimated k cat/K m of 2.0 · 10 6 M)1 Æs)1.The X-ray structure of PpiA was solved by molecular replacement, and refined to a resolution of 2.6 A ˚ with R and R free According to the World Health Organizatio