1V4G

Crystal Structure of gamma-Glutamylcysteine Synthetase from Escherichia coli B

DOI: 10.2210/pdb1V4G/pdb

Classification: LIGASE
Organism(s): Escherichia coli
Expression System: Escherichia coli
Mutation(s): Yes

Deposited: 2003-11-13 Released: 2004-10-05
Deposition Author(s): Hibi, T., Nii, H., Nakatsu, T., Kato, H., Hiratake, J., Oda, J.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.50 Å
R-Value Free: 0.236
R-Value Work: 0.206
R-Value Observed: 0.207

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

Crystal structure of gamma-glutamylcysteine synthetase: insights into the mechanism of catalysis by a key enzyme for glutathione homeostasis

Hibi, T., Nii, H., Nakatsu, T., Kimura, A., Kato, H., Hiratake, J., Oda, J.

(2004) Proc Natl Acad Sci U S A 101: 15052-15057

PubMed: 15477603 Search on PubMedSearch on PubMed Central
DOI: 10.1073/pnas.0403277101
Primary Citation of Related Structures:
1VA6, 1V4G

PubMed Abstract:

Gamma-glutamylcysteine synthetase (gammaGCS), a rate-limiting enzyme in glutathione biosynthesis, plays a central role in glutathione homeostasis and is a target for development of potential therapeutic agents against parasites and cancer. We have determined the crystal structures of Escherichia coli gammaGCS unliganded and complexed with a sulfoximine-based transition-state analog inhibitor at resolutions of 2.5 and 2.1 A, respectively. In the crystal structure of the complex, the bound inhibitor is phosphorylated at the sulfoximido nitrogen and is coordinated to three Mg2+ ions. The cysteine-binding site was identified; it is formed inductively at the transition state. In the unliganded structure, an open space exists around the representative cysteine-binding site and is probably responsible for the competitive binding of glutathione. Upon inhibitor binding, the side chains of Tyr-241 and Tyr-300 turn, forming a hydrogen-bonding triad with the carboxyl group of the inhibitor's cysteine moiety, allowing this moiety to fit tightly into the cysteine-binding site with concomitant accommodation of its side chain into a shallow pocket. This movement is caused by a conformational change of a switch loop (residues 240-249). Based on this crystal structure, the cysteine-binding sites of mammalian and parasitic gammaGCSs were predicted by multiple sequence alignment, although no significant sequence identity exists between the E. coli gammaGCS and its eukaryotic homologues. The identification of this cysteine-binding site provides important information for the rational design of novel gammaGCS inhibitors.

Related Citations:

Escherichia coli B gamma-glutamylcysteine synthetase: modification, purification, crystallization and preliminary crystallographic analysis
Hibi, T., Hisada, H., Nakatsu, T., Kato, H., Oda, J.
(2002) Acta Crystallogr D Biol Crystallogr 58: 316

Organizational Affiliation:

Department of Bioscience, Fukui Prefectural University, Fukui 910-1195, Japan.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Glutamate--cysteine ligase	A, B, C, D	518	Escherichia coli	Mutation(s): 5 Gene Names: gsh-I EC: 6.3.2.2
Find proteins for P0A6W9 (Escherichia coli (strain K12)) Explore P0A6W9 Go to UniProtKB: P0A6W9
Protein Feature View Expand
Reference Sequence