1UIP

ADENOSINE DEAMINASE (HIS 238 GLU MUTANT)

1UIP の概要

• エントリーDOI: 10.2210/pdb1uip/pdb
• 分子名称: ADENOSINE DEAMINASE, ZINC ION, PURINE RIBOSIDE, ... (4 entities in total)
• 機能のキーワード: hydrolase, nucleotide metabolism, zinc cofactor tim barrel
• 由来する生物種: Mus musculus (house mouse)
• 細胞内の位置: Cell membrane; Peripheral membrane protein; Extracellular side (By similarity): P03958
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 40024.80

構造登録者

Wilson, D.K.,Quiocho, F.A. (登録日: 1996-08-30, 公開日: 1997-06-24, 最終更新日: 2024-02-14)

主引用文献

Sideraki, V.,Wilson, D.K.,Kurz, L.C.,Quiocho, F.A.,Rudolph, F.B.
Site-directed mutagenesis of histidine 238 in mouse adenosine deaminase: substitution of histidine 238 does not impede hydroxylate formation.
Biochemistry, 35:15019-15028, 1996

PubMed Abstract: His 238, a conserved amino acid located in hydrogen-bonding distance from C-6 of the substrate in the active site of murine adenosine deaminase (mADA) and postulated to play an important role in catalysis, was altered into an alanine, a glutamate, and an arginine using site-directed mutagenesis. The Ala and Glu substitutions did not result in changes of the secondary or tertiary structure, while the Arg mutation caused local perturbations in tertiary structure and quenched the emission of one or more enzyme tryptophans. Neither the Glu or Arg mutations affected substrate binding affinity. By contrast, the Ala mutation enhanced substrate and inhibitor binding by 20-fold. The most inactive of the mutants, Glu 238, had a kcat/K(m) 4 x 10(-6) lower than the wild-type value, suggesting that a positive charge on His 238 is important for proper catalytic function. The Ala 238 mutant was the most active ADA, with a kcat/K(m) 2 x 10(-3) lower than the wild-type value. NMR spectroscopy and crystallography revealed that this mutant is able to catalyze hydration of purine riboside, a ground-state analog of the reaction. These results collectively show that His 238 is not required for formation of the hydroxylate used in the deamination and may instead have an important electrostatic role.

PubMed: 8942668
DOI: 10.1021/bi961427e

実験手法

X-RAY DIFFRACTION (2.4 Å)