tailieunhanh - Báo cáo khoa học: X-ray structure of peptidyl-prolyl cis–trans isomerase A from Mycobacterium tuberculosis

Peptidyl-prolylcis–transisomerases (EC ) 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 heat-shock response. Here we report the soluble expression of recombinant Mycobacterium tuberculosispeptidyl-prolyl cis–transisomerasePpiAinEscherichiacoli, togetherwithan investigationof its structure andbiochemical properties | Eur. J. Biochem. 271 4107-4113 2004 FEBS 2004 doi X-ray structure of peptidyl-prolyl cis-trans isomerase A from Mycobacterium tuberculosis Lena M. Henriksson1 Patrik Johansson1 Torsten Unge1 and Sherry L. Mowbray2 1Department of Cell and Molecular Biology Uppsala University Sweden department of Molecular Biology Swedish University of Agricultural Sciences Uppsala Sweden Peptidyl-prolyl cis-trans isomerases EC 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 kcat Km of X 106 M-1-s-1. The X-ray structure of PpiA was solved by molecular replacement and refined to a resolution of Ay with R and Rfree values of and respectively. Comparisons to known structures show that the PpiA represents a slight variation on the peptidyl-prolyl cis-trans isomerase fold previously not represented in the Protein Data Bank. Inspection of the active site suggests that specificity for substrates and cyclosporin A will be similar to that found for most other enzymes of this structural family. Comparison to the sequence of the second M. tuberculosis enzyme PpiB suggests that binding of peptide substrates as well as cyclosporin A may differ in that case. Keywords cyclophilin peptidyl-prolyl cis-trans isomerase PPIase rotamase Rv0009. According to the World Health Organization http Mycobacterium tuberculosis the causative pathogen of tuberculosis currently infects one-third of the world s population and results in 2 million .