1cnq

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spinqualitylabelsall models 1cnq, resolution 2.27Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

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 with F6P, ZN and PO4 as ligands. This structure superseeds the now removed PDB entry 1BFL. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 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 Tue Nov 20 12:36:23 2007