Literature summary for 6.3.2.2 extracted from

Biterova, E.I.; Barycki, J.J.
Structural basis for feedback and pharmacological inhibition of Saccharomyces cerevisiae glutamate cysteine ligase (2010), J. Biol. Chem., 285, 14459-14466.

Crystallization (Commentary)

Crystallization (Comment)	Organism
structure of the GCL-glutathione complex to 2.5 A resolution indicates that the inhibitor occupies both the glutamate- and the presumed cysteine-binding site and disrupts the previously observed Mg2+-coordination in the ATP-binding site. The structure of the complex with mechanism-based inhibitor L-buthionine-S-sulfoximine to 2.2 A resolution confirms that L-buthionine-S-sulfoximine is phosphorylated on the sulfoximine nitrogen to generate the inhibitory species and reveals contacts that likely contribute to transition state stabilization	Saccharomyces cerevisiae

Crystallization (Comment)

Organism

structure of the GCL-glutathione complex to 2.5 A resolution indicates that the inhibitor occupies both the glutamate- and the presumed cysteine-binding site and disrupts the previously observed Mg2+-coordination in the ATP-binding site. The structure of the complex with mechanism-based inhibitor L-buthionine-S-sulfoximine to 2.2 A resolution confirms that L-buthionine-S-sulfoximine is phosphorylated on the sulfoximine nitrogen to generate the inhibitory species and reveals contacts that likely contribute to transition state stabilization

Saccharomyces cerevisiae

Protein Variants

Protein Variants	Comment	Organism
C266A	about 2fold increase in both Km and Ki value	Saccharomyces cerevisiae
C266S	about 2fold increase in both Km and Ki value	Saccharomyces cerevisiae

Inhibitors

Inhibitors	Comment	Organism
gamma-L-Glu-L-Cys	-	Saccharomyces cerevisiae
glutathione	feedback-regulation. The structure of the GCL-glutathione complex to 2.5 A resolution indicates that the inhibitor occupies both the glutamate- and the presumed cysteine-binding site and disrupts the previously observed Mg2+-coordination in the ATP-binding site	Saccharomyces cerevisiae
L-buthionine-S-sulfoximine	mechanism-based inhibitor. The crystal structure of the enzyme complex to 2.2 A resolution confirms that L-buthionine-S-sulfoximine is phosphorylated on the sulfoximine nitrogen to generate the inhibitory species and reveals contacts that likely contribute to transition state stabilization	Saccharomyces cerevisiae
L-Glu	-	Saccharomyces cerevisiae

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism
0.08	-	ATP	wild-type, pH 8.0	Saccharomyces cerevisiae
0.17	-	L-Cys	wild-type, pH 8.0	Saccharomyces cerevisiae
1.21	-	L-Glu	wild-type, pH 8.0	Saccharomyces cerevisiae
1.93	-	L-Glu	mutant C266A, pH 8.0	Saccharomyces cerevisiae
2.15	-	L-Glu	mutant C266S, pH 8.0	Saccharomyces cerevisiae

Organism

Organism	UniProt	Comment	Textmining
Saccharomyces cerevisiae	P32477	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + L-Glu + L-Cys	-	Saccharomyces cerevisiae	ADP + phosphate + gamma-L-Glu-L-Cys	-	?

Ki Value [mM]

Ki Value [mM]	Ki Value maximum [mM]	Inhibitor	Comment	Organism
2.12	-	gamma-L-Glu-L-Cys	wild-type, pH 8.0	Saccharomyces cerevisiae
3.93	-	L-Glu	mutant C266S, pH 8.0	Saccharomyces cerevisiae
4.7	-	L-Glu	mutant C266A, pH 8.0	Saccharomyces cerevisiae