1cnq
From Proteopedia
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| , resolution 2.27Å | |||||||
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| Ligands: | , , | ||||||
| Activity: | Fructose-bisphosphatase, with EC number 3.1.3.11 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
FRUCTOSE-1,6-BISPHOSPHATASE COMPLEXED WITH FRUCTOSE-6-PHOSPHATE AND ZINC IONS
Overview
A disordered loop (loop 52-72, residues 52-72) in crystal structures of fructose-1,6-bisphosphatase (FBPase) has been implicated in regulatory and catalytic phenomena by studies in directed mutation. A crystal structure of FBPase in a complex with three zinc cations and the products fructose 6-phosphate (F6P) and phosphate (Pi) reveals loop 52-72 for the first time in a well-defined conformation with strong electron density. Loop 52-57 interacts primarily with the active site of its own subunit. Asp68 of the loop hydrogen bonds with Arg276 and a zinc cation located at the putative potassium activation site. Leu56 and Tyr57 of the loop pack against hydrophobic residues from two separate subunits of FBPase. A mechanism of allosteric regulation of catalysis is presented, in which AMP, by binding to its allosteric pocket, displaces loop 52-72 from the active site. Furthermore, the current structure suggests that both the alpha- and beta-anomers of F6P can be substrates in the reverse reaction catalyzed by FBPase. Mechanisms of catalysis are proposed for the reverse reaction in which Asp121 serves as a catalytic base for the alpha-anomer and Glu280 serves as a catalytic base for the beta-anomer.
About this Structure
1CNQ is a Single protein structure of sequence from Sus scrofa. This structure supersedes the now removed PDB entry 1BFL. Full crystallographic information is available from OCA.
Reference
Role of a dynamic loop in cation activation and allosteric regulation of recombinant porcine fructose-1,6-bisphosphatase., Choe JY, Poland BW, Fromm HJ, Honzatko RB, Biochemistry. 1998 Aug 18;37(33):11441-50. PMID:9708979
Page seeded by OCA on Sun Mar 30 19:25:06 2008
