1JKC

HUMAN LYSOZYME MUTANT WITH TRP 109 REPLACED BY PHE

1JKC の概要

• エントリーDOI: 10.2210/pdb1jkc/pdb
• 分子名称: LYSOZYME, NITRATE ION (3 entities in total)
• 機能のキーワード: hydrolase, muramidase, hydrolase (o-glycosyl), glycosidase, lysozyme
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Secreted: P61626
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14805.67

構造登録者

Muraki, M.,Harata, K.,Goda, S.,Nagahora, H. (登録日: 1996-11-13, 公開日: 1997-05-15, 最終更新日: 2024-11-20)

主引用文献

Muraki, M.,Goda, S.,Nagahora, H.,Harata, K.
Importance of van der Waals contact between Glu 35 and Trp 109 to the catalytic action of human lysozyme.
Protein Sci., 6:473-476, 1997

PubMed Abstract: The importance of van der Waals contact between Glu 35 and Trp 109 to the active-site structure and the catalytic properties of human lysozyme (HL) has been investigated by site-directed mutagenesis. The X-ray analysis of mutant HLs revealed that both the replacement of Glu 35 by Asp or Ala, and the replacement of Trp 109 by Phe or Ala resulted in a significant but localized change in the active-site cleft geometry. A prominent movement of the backbone structure was detected in the region of residues 110 to 120 and in the region of residues 100 to 115 for the mutations concerning Glu 35 and Trp 109, respectively. Accompanied by the displacement of the main-chain atoms with a maximal deviation of C alpha atom position ranging from 0.7 A to 1.0 A, the mutant HLs showed a remarkable change in the catalytic properties against Micrococcus luteus cell substrate as compared with native HL. Although the replacement of Glu 35 by Ala completely abolished the lytic activity, HL-Asp 35 mutant retained a weak but a certain lytic activity, showing the possible involvement of the side-chain carboxylate group of Asp 35 in the catalytic action. The kinetic consequence derived from the replacement of Trp 109 by Phe or Ala together with the result of the structural change suggested that the structural detail of the cleft lobe composed of the residues 100 to 115 centered at Ala 108 was responsible for the turnover in the reaction of HL against the bacterial cell wall substrate. The results revealed that the van der Waals contact between Glu 35 and Trp 109 was an essential determinant in the catalytic action of HL.

PubMed: 9041653

実験手法

X-RAY DIFFRACTION (1.6 Å)