2skc
From Proteopedia
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PYRIDOXAL PHOSPHORYLASE B IN COMPLEX WITH FLUOROPHOSPHATE, GLUCOSE AND INOSINE-5'-MONOPHOSPHATE
Overview
It has been established that phosphate analogues can activate glycogen, phosphorylase reconstituted with pyridoxal in place of the natural, cofactor pyridoxal 5'-phosphate (Change YC. McCalmont T, Graves DJ. 1983., Biochemistry 22:4987-4993). Pyridoxal phosphorylase b has been studied by, kinetic, ultracentrifugation, and X-ray crystallographic experiments. In, solution, the catalytically active species of pyridoxal phosphorylase b, adopts a conformation that is more R-state-like than that of native, phosphorylase b, but an inactive dimeric species of the enzyme can be, stabilized by activator phosphite in combination with the T-state, inhibitor glucose. Co-crystals of pyridoxal phosphorylase b complexed with, either phosphite, phosphate, or fluorophosphate, the inhibitor glucose, and the weak activator IMP were grown in space group P4(3)2(1)2, with, native-like unit cell dimensions, and the structures of the complexes have, been refined to give crystallographic R factors of 18.5-19.2%, for data, between 8 and 2.4 A resolution. The anions bind tightly at the catalytic, site in a similar but not identical position to that occupied by the, cofactor 5'-phosphate group in the native enzyme (phosphorus to phosphorus, atoms distance = 1.2 A). The structural results show that the structures, of the pyridoxal phosphorylase b-anion-glucose-IMP complexes are overall, similar to the glucose complex of native T-state phosphorylase b., Structural comparisons suggest that the bound anions, in the position, observed in the crystal, might have a structural role for effective, catalysis.
About this Structure
2SKC is a Single protein structure of sequence from Oryctolagus cuniculus with GLC, PLP, FPO and IMP as ligands. This structure superseeds the now removed PDB entry 1SKC. Active as Phosphorylase, with EC number 2.4.1.1 Full crystallographic information is available from OCA.
Reference
Activator anion binding site in pyridoxal phosphorylase b: the binding of phosphite, phosphate, and fluorophosphate in the crystal., Oikonomakos NG, Zographos SE, Tsitsanou KE, Johnson LN, Acharya KR, Protein Sci. 1996 Dec;5(12):2416-28. PMID:8976550
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