1aqf
From Proteopedia
|
PYRUVATE KINASE FROM RABBIT MUSCLE WITH MG, K, AND L-PHOSPHOLACTATE
Overview
The structure of rabbit muscle pyruvate kinase crystallized as a complex, with Mg2+, K+, and L-phospholactate (L-P-lactate) has been solved and, refined to 2.7 A resolution. The crystals, grown from solutions of, polyethylene glycol 8000 at pH 7.5, belong to the space group P2(1) and, have unit cell parameters a = 144.4 A, b = 112.6 A, c = 171.2 A, and beta, = 93.7 degrees. The asymmetric unit contains two tetramers. The crystal, structure reveals that the eight subunits within the asymmetric unit adopt, several different conformations. These conformations are characterized by, differences in the relative positions of protein domains A and B, resulting in different degrees of closure of the active site cleft that, occupies the interface between these two domains. The global, conformational differences may be described as rotations of the B domain, with respect to the (beta/alpha)8-barrel of the A domain. Carbon atoms of, the backbone in domain B rotate >20 degrees from the most open to the most, closed subunit. The different conformations among subunits within the, asymmetric unit are accompanied by 3-3.8 A shifts in the position of Mg2+, and a significant change in the orientation of the phenyl ring of Phe 243., In all of the subunits, Mg2+ coordinates to the protein through the, carboxylate side chains of Glu 271 and Asp 295. In the subunit having the, most closed conformation, Mg2+ also coordinates to the carboxylate oxygen, the bridging ester oxygen, and a nonbridging phosphoryl oxygen of, L-P-lactate. Mg2+ to L-P-lactate coordination is missing in subunits, exhibiting a more open conformation. K+ coordinates to four protein, ligands and to a phosphoryl oxygen of the L-P-lactate. The position and, liganding of K+ are unaffected by the different conformations of the, subunits. The side chain of Arg 72, Mg2+, and K+ provides a locus of, positive charge for the phosphate moiety of the analog in the closed, subunit.
About this Structure
1AQF is a Single protein structure of sequence from Oryctolagus cuniculus with K, MG and PEQ as ligands. Active as Pyruvate kinase, with EC number 2.7.1.40 Full crystallographic information is available from OCA.
Reference
Ligand-induced domain movement in pyruvate kinase: structure of the enzyme from rabbit muscle with Mg2+, K+, and L-phospholactate at 2.7 A resolution., Larsen TM, Benning MM, Wesenberg GE, Rayment I, Reed GH, Arch Biochem Biophys. 1997 Sep 15;345(2):199-206. PMID:9308890
Page seeded by OCA on Tue Nov 20 11:02:48 2007
