1BG0

TRANSITION STATE STRUCTURE OF ARGININE KINASE

1BG0 の概要

• エントリーDOI: 10.2210/pdb1bg0/pdb
• 分子名称: ARGININE KINASE, NITRATE ION, MAGNESIUM ION, ... (6 entities in total)
• 機能のキーワード: arginine kinase, creatine kinase, phosphagen kinase, transition state analog, adenosine triphosphate, transferase, kinase
• 由来する生物種: Limulus polyphemus (Atlantic horseshoe crab)
• 細胞内の位置: Cytoplasm: P51541
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 40869.29

構造登録者

Zhou, G.,Somasundaram, T.,Blanc, E.,Parthasarathy, G.,Ellington, W.R.,Chapman, M.S. (登録日: 1998-06-03, 公開日: 1998-10-14, 最終更新日: 2024-05-22)

主引用文献

Zhou, G.,Somasundaram, T.,Blanc, E.,Parthasarathy, G.,Ellington, W.R.,Chapman, M.S.
Transition state structure of arginine kinase: implications for catalysis of bimolecular reactions.
Proc.Natl.Acad.Sci.USA, 95:8449-8454, 1998

PubMed Abstract: Arginine kinase belongs to the family of enzymes, including creatine kinase, that catalyze the buffering of ATP in cells with fluctuating energy requirements and that has been a paradigm for classical enzymological studies. The 1.86-A resolution structure of its transition-state analog complex, reported here, reveals its active site and offers direct evidence for the importance of precise substrate alignment in the catalysis of bimolecular reactions, in contrast to the unimolecular reactions studied previously. In the transition-state analog complex studied here, a nitrate mimics the planar gamma-phosphoryl during associative in-line transfer between ATP and arginine. The active site is unperturbed, and the reactants are not constrained covalently as in a bisubstrate complex, so it is possible to measure how precisely they are pre-aligned by the enzyme. Alignment is exquisite. Entropic effects may contribute to catalysis, but the lone-pair orbitals are also aligned close enough to their optimal trajectories for orbital steering to be a factor during nucleophilic attack. The structure suggests that polarization, strain toward the transition state, and acid-base catalysis also contribute, but, in contrast to unimolecular enzyme reactions, their role appears to be secondary to substrate alignment in this bimolecular reaction.

PubMed: 9671698
DOI: 10.1073/pnas.95.15.8449

実験手法

X-RAY DIFFRACTION (1.86 Å)