2QBV: Crystal Structure Of Intracellular Chorismate Mutase From Mycobacterium Tuberculosis

Citation:
Abstract
The Rv0948c gene from Mycobacterium tuberculosis H(37)R(v) encodes a 90 amino acid protein as the natural gene product with chorismate mutase (CM) activity. The protein, 90-MtCM, exhibits Michaelis-Menten kinetics with a k(cat) of 5.5+/-0.2s(-1) and a K(m) of 1500+/-100microm at 37 degrees C and pH7.5. The 2.0A X-ray structure shows that 90-MtCM is an all alpha-helical homodimer (Protein Data Bank ID: 2QBV) with the topology of Escherichia coli CM (EcCM), and that both protomers contribute to each catalytic site. Superimposition onto the structure of EcCM and the sequence alignment shows that the C-terminus helix3 is shortened. The absence of two residues in the active site of 90-MtCM corresponding to Ser84 and Gln88 of EcCM appears to be one reason for the low k(cat). Hence, 90-MtCM belongs to a subfamily of alpha-helical AroQ CMs termed AroQ(delta.) The CM gene (y2828) from Yersinia pestis encodes a 186 amino acid protein with an N-terminal signal peptide that directs the protein to the periplasm. The mature protein, *YpCM, exhibits Michaelis-Menten kinetics with a k(cat) of 70+/-5s(-1) and K(m) of 500+/-50microm at 37 degrees C and pH7.5. The 2.1A X-ray structure shows that *YpCM is an all alpha-helical protein, and functions as a homodimer, and that each protomer has an independent catalytic unit (Protein Data Bank ID: 2GBB). *YpCM belongs to the AroQ(gamma) class of CMs, and is similar to the secreted CM (Rv1885c, *MtCM) from M.tuberculosis.
PDB ID: 2QBVDownload
MMDB ID: 47283
PDB Deposition Date: 2007/6/18
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 2QBV: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 2QBV
Label Count Molecule
Proteins (2 molecules)
2
Chorismate Mutase
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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