2gci
From Proteopedia
(New page: 200px<br /><applet load="2gci" size="350" color="white" frame="true" align="right" spinBox="true" caption="2gci, resolution 1.60Å" /> '''The 1,1-proton trans...) |
|||
| Line 4: | Line 4: | ||
==Overview== | ==Overview== | ||
| - | + | Alpha-methylacyl-CoA racemases are essential enzymes for branched-chain fatty acid metabolism. Their reaction mechanism and the structural basis of their wide substrate specificity are poorly understood. High-resolution crystal structures of Mycobacterium tuberculosis alpha-methylacyl-CoA racemase (MCR) complexed with substrate molecules show the active site geometry required for catalysis of the interconversion of (2S) and (2R)-methylacyl-CoA. The thioester oxygen atom and the 2-methyl group are in a cis-conformation with respect to each other. The thioester oxygen atom fits into an oxyanion hole and the 2-methyl group points into a hydrophobic pocket. The active site geometry agrees with a 1,1-proton transfer mechanism in which the acid/base-pair residues are His126 and Asp156. The structures of the complexes indicate that the acyl chains of the S-substrate and the R-substrate bind in an S-pocket and an R-pocket, respectively. A unique feature of MCR is a large number of methionine residues in the acyl binding region, located between the S-pocket and the R-pocket. It appears that the (S) to (R) interconversion of the 2-methylacyl chiral center is coupled to a movement of the acyl group over this hydrophobic, methionine-rich surface, when moving from its S-pocket to its R-pocket, whereas the 2-methyl moiety and the CoA group remain fixed in their respective pockets. | |
==About this Structure== | ==About this Structure== | ||
| Line 10: | Line 10: | ||
==Reference== | ==Reference== | ||
| - | The | + | The catalysis of the 1,1-proton transfer by alpha-methyl-acyl-CoA racemase is coupled to a movement of the fatty acyl moiety over a hydrophobic, methionine-rich surface., Bhaumik P, Schmitz W, Hassinen A, Hiltunen JK, Conzelmann E, Wierenga RK, J Mol Biol. 2007 Apr 6;367(4):1145-61. Epub 2007 Jan 27. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17320106 17320106] |
[[Category: Alpha-methylacyl-CoA racemase]] | [[Category: Alpha-methylacyl-CoA racemase]] | ||
[[Category: Mycobacterium tuberculosis]] | [[Category: Mycobacterium tuberculosis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bhaumik, P.]] | [[Category: Bhaumik, P.]] | ||
| - | [[Category: Wierenga, R | + | [[Category: Wierenga, R K.]] |
[[Category: GOL]] | [[Category: GOL]] | ||
[[Category: MRR]] | [[Category: MRR]] | ||
| Line 24: | Line 24: | ||
[[Category: racemase]] | [[Category: racemase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:30:21 2008'' |
Revision as of 15:30, 21 February 2008
|
The 1,1-proton transfer reaction mechanism by alpha-methylacyl-CoA racemase is catalyzed by an asparte/histidine pair and involves a smooth, methionine-rich surface for binding the fatty acyl moiety
Overview
Alpha-methylacyl-CoA racemases are essential enzymes for branched-chain fatty acid metabolism. Their reaction mechanism and the structural basis of their wide substrate specificity are poorly understood. High-resolution crystal structures of Mycobacterium tuberculosis alpha-methylacyl-CoA racemase (MCR) complexed with substrate molecules show the active site geometry required for catalysis of the interconversion of (2S) and (2R)-methylacyl-CoA. The thioester oxygen atom and the 2-methyl group are in a cis-conformation with respect to each other. The thioester oxygen atom fits into an oxyanion hole and the 2-methyl group points into a hydrophobic pocket. The active site geometry agrees with a 1,1-proton transfer mechanism in which the acid/base-pair residues are His126 and Asp156. The structures of the complexes indicate that the acyl chains of the S-substrate and the R-substrate bind in an S-pocket and an R-pocket, respectively. A unique feature of MCR is a large number of methionine residues in the acyl binding region, located between the S-pocket and the R-pocket. It appears that the (S) to (R) interconversion of the 2-methylacyl chiral center is coupled to a movement of the acyl group over this hydrophobic, methionine-rich surface, when moving from its S-pocket to its R-pocket, whereas the 2-methyl moiety and the CoA group remain fixed in their respective pockets.
About this Structure
2GCI is a Single protein structure of sequence from Mycobacterium tuberculosis with and as ligands. Active as Alpha-methylacyl-CoA racemase, with EC number 5.1.99.4 Full crystallographic information is available from OCA.
Reference
The catalysis of the 1,1-proton transfer by alpha-methyl-acyl-CoA racemase is coupled to a movement of the fatty acyl moiety over a hydrophobic, methionine-rich surface., Bhaumik P, Schmitz W, Hassinen A, Hiltunen JK, Conzelmann E, Wierenga RK, J Mol Biol. 2007 Apr 6;367(4):1145-61. Epub 2007 Jan 27. PMID:17320106
Page seeded by OCA on Thu Feb 21 17:30:21 2008
