1ABB

CONTROL OF PHOSPHORYLASE B CONFORMATION BY A MODIFIED COFACTOR: CRYSTALLOGRAPHIC STUDIES ON R-STATE GLYCOGEN PHOSPHORYLASE RECONSTITUTED WITH PYRIDOXAL 5'-DIPHOSPHATE

1ABB の概要

• エントリーDOI: 10.2210/pdb1abb/pdb
• 分子名称: GLYCOGEN PHOSPHORYLASE B, SULFATE ION, PYRIDOXAL-5'-DIPHOSPHATE, ... (4 entities in total)
• 機能のキーワード: glycogen phosphorylase
• 由来する生物種: Oryctolagus cuniculus (rabbit)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 385743.16

構造登録者

Leonidas, D.D.,Oikonomakos, N.G.,Papageorgiou, A.C.,Acharya, K.R.,Barford, D.,Johnson, L.N. (登録日: 1992-04-09, 公開日: 1993-10-31, 最終更新日: 2024-11-20)

主引用文献

Leonidas, D.D.,Oikonomakos, N.G.,Papageorgiou, A.C.,Acharya, K.R.,Barford, D.,Johnson, L.N.
Control of phosphorylase b conformation by a modified cofactor: crystallographic studies on R-state glycogen phosphorylase reconstituted with pyridoxal 5'-diphosphate.
Protein Sci., 1:1112-1122, 1992

PubMed Abstract: Previous crystallographic studies on glycogen phosphorylase have described the different conformational states of the protein (T and R) that represent the allosteric transition and have shown how the properties of the 5'-phosphate group of the cofactor pyridoxal phosphate are influenced by these conformational states. The present work reports a study on glycogen phosphorylase b (GPb) complexed with a modified cofactor, pyridoxal 5'-diphosphate (PLPP), in place of the natural cofactor. Solution studies (Withers, S.G., Madsen, N.B., & Sykes, B.D., 1982, Biochemistry 21, 6716-6722) have shown that PLPP promotes R-state properties of the enzyme indicating that the cofactor can influence the conformational state of the protein. GPb complexed with pyridoxal 5'-diphosphate (PLPP) has been crystallized in the presence of IMP and ammonium sulfate in the monoclinic R-state crystal form and the structure refined from X-ray data to 2.8 A resolution to a crystallographic R value of 0.21. The global tertiary and quaternary structure in the vicinity of the Ser 14 and the IMP sites are nearly identical to those observed for the R-state GPb-AMP complex. At the catalytic site the second phosphate of PLPP is accommodated with essentially no change in structure from the R-state structure and is involved in interactions with the side chains of two lysine residues (Lys 568 and Lys 574) and the main chain nitrogen of Arg 569. Superposition of the T-state structure shows that were the PLPP to be incorporated into the T-state structure there would be a close contact with the 280s loop (residues 282-285) that would encourage the T to R allosteric transition. The second phosphate of the PLPP occupies a site that is distinct from other dianionic binding sites that have been observed for glucose-1-phosphate and sulfate (in the R state) and for heptulose-2-phosphate (in the T state). The results indicate mobility in the dianion recognition site, and the precise position is dependent on other linkages to the dianion. In the modified cofactor the second phosphate site is constrained by the covalent link to the first phosphate of PLPP. The observed position in the crystal suggests that it is too far from the substrate site to represent a site for catalysis.

PubMed: 1304390

実験手法

X-RAY DIFFRACTION (2.8 Å)