1tuu
From Proteopedia
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| , resolution 2.50Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , , and | ||||||
| Gene: | ACKA, ACK (Methanosarcina thermophila) | ||||||
| Activity: | Acetate kinase, with EC number 2.7.2.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Acetate Kinase crystallized with ATPgS
Overview
Acetate kinase catalyzes transfer of the gamma-phosphate of ATP to acetate. The only crystal structure reported for acetate kinase is the homodimeric enzyme from Methanosarcina thermophila containing ADP and sulfate in the active site (Buss, K. A., Cooper, D. C., Ingram-Smith, C., Ferry, J. G., Sanders, D. A., and Hasson, M. S. (2001) J. Bacteriol. 193, 680-686). Here we report two new crystal structure of the M. thermophila enzyme in the presence of substrate and transition state analogs. The enzyme co-crystallized with the ATP analog adenosine 5'-[gamma-thio]triphosphate contained AMP adjacent to thiopyrophosphate in the active site cleft of monomer B. The enzyme co-crystallized with ADP, acetate, Al(3+), and F(-) contained a linear array of ADP-AlF(3)-acetate in the active site cleft of monomer B. Together, the structures clarify the substrate binding sites and support a direct in-line transfer mechanism in which AlF(3) mimics the meta-phosphate transition state. Monomers A of both structures contained ADP and sulfate, and the active site clefts were closed less than in monomers B, suggesting that domain movement contributes to catalysis. The finding that His(180) was in close proximity to AlF(3) is consistent with a role for stabilization of the meta-phosphate that is in agreement with a previous report indicating that this residue is essential for catalysis. Residue Arg(241) was also found adjacent to AlF(3), consistent with a role for stabilization of the transition state. Kinetic analyses of Arg(241) and Arg(91) replacement variants indicated that these residues are essential for catalysis and also indicated a role in binding acetate.
About this Structure
1TUU is a Single protein structure of sequence from Methanosarcina thermophila. Full crystallographic information is available from OCA.
Reference
Structural and kinetic analyses of arginine residues in the active site of the acetate kinase from Methanosarcina thermophila., Gorrell A, Lawrence SH, Ferry JG, J Biol Chem. 2005 Mar 18;280(11):10731-42. Epub 2005 Jan 12. PMID:15647264
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