1w74

From Proteopedia

Revision as of 03:07, 21 November 2007

X-RAY STRUCTURE OF PEPTIDYL-PROLYL CIS-TRANS ISOMERASE A, PPIA, RV0009, FROM MYCOBACTERIUM TUBERCULOSIS.

Overview

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 heat-shock 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 2.0 x 10(6), m(-1).s(-1). The X-ray structure of PpiA was solved by molecular, replacement, and refined to a resolution of 2.6 A with R and Rfree values, of 21.3% and 22.9%, 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.

About this Structure

1W74 is a Single protein structure of sequence from Mycobacterium tuberculosis. Active as Peptidylprolyl isomerase, with EC number 5.2.1.8 Full crystallographic information is available from OCA.

Reference

X-ray structure of peptidyl-prolyl cis-trans isomerase A from Mycobacterium tuberculosis., Henriksson LM, Johansson P, Unge T, Mowbray SL, Eur J Biochem. 2004 Oct;271(20):4107-13. PMID:15479239

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