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Sci Rep. 2014 Jan 23;4:3827. doi: 10.1038/srep03827.

Structural basis for the active site inhibition mechanism of human kidney-type glutaminase (KGA).

Author information

1
Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543.
2
1] Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543 [2] Mechanobiology Institute Singapore, National University of Singapore, Singapore 117411.

Abstract

Glutaminase is a metabolic enzyme responsible for glutaminolysis, a process harnessed by cancer cells to feed their accelerated growth and proliferation. Among the glutaminase isoforms, human kidney-type glutaminase (KGA) is often upregulated in cancer and is thus touted as an attractive drug target. Here we report the active site inhibition mechanism of KGA through the crystal structure of the catalytic domain of KGA (cKGA) in complex with 6-diazo-5-oxo-L-norleucine (DON), a substrate analogue of glutamine. DON covalently binds with the active site Ser286 and interacts with residues such as Tyr249, Asn335, Glu381, Asn388, Tyr414, Tyr466 and Val484. The nucleophilic attack of Ser286 sidechain on DON releases the diazo group (N2) from the inhibitor and results in the formation of an enzyme-inhibitor complex. Mutational studies confirmed the key role of these residues in the activity of KGA. This study will be important in the development of KGA active site inhibitors for therapeutic interventions.

PMID:
24451979
PMCID:
PMC4929687
DOI:
10.1038/srep03827
[Indexed for MEDLINE]
Free PMC Article

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