1gll
ESCHERICHIA COLI GLYCEROL KINASE MUTANT WITH BOUND ATP ANALOG SHOWING SUBSTANTIAL DOMAIN MOTION
|
OverviewOverview
Escherichia coli glycerol kinase (GK) displays "half-of-the-sites", reactivity toward ATP and allosteric regulation by fructose 1, 6-bisphosphate (FBP), which has been shown to promote dimer-tetramer, assembly and to inhibit only tetramers. To probe the role of tetramer, assembly, a mutation (Ser58-->Trp) was designed to sterically block, formation of the dimer-dimer interface near the FBP binding site [Ormo, M., Bystrom, C., and Remington, S. J. (1998) Biochemistry 37, 16565-16572]. The substitution did not substantially change the Michaelis, constants or alter allosteric regulation of GK by a second effector, the, phosphocarrier protein IIAGlc; however, it eliminated FBP inhibition., Crystal structures of GK in complex with different nontransferable ATP, analogues and glycerol revealed an asymmetric dimer with one subunit, adopting an open conformation and the other adopting the closed, conformation found in previously determined structures. The conformational, difference is produced by a approximately 6.0 degrees rigid-body rotation, of the N-terminal domain with respect to the C-terminal domain, similar to, that observed for hexokinase and actin, members of the same ATPase, superfamily. Two of the ATP analogues bound in nonproductive conformations, in both subunits. However, beta, gamma-difluoromethyleneadenosine, 5'-triphosphate (AMP-PCF2P), a potent inhibitor of GK, bound, nonproductively in the closed subunit and in a putative productive, conformation in the open subunit, with the gamma-phosphate placed for, in-line transfer to glycerol. This asymmetry is consistent with, "half-of-the-sites" reactivity and suggests that the inhibition of GK by, FBP is due to restriction of domain motion.
About this StructureAbout this Structure
1GLL is a Single protein structure of sequence from Escherichia coli with MG, ACP and GOL as ligands. Active as Glycerol kinase, with EC number 2.7.1.30 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of Escherichia coli glycerol kinase variant S58-->W in complex with nonhydrolyzable ATP analogues reveal a putative active conformation of the enzyme as a result of domain motion., Bystrom CE, Pettigrew DW, Branchaud BP, O'Brien P, Remington SJ, Biochemistry. 1999 Mar 23;38(12):3508-18. PMID:10090737
Page seeded by OCA on Tue Nov 20 16:09:15 2007