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

K Thangavelu1, Qing Yun Chong1, Boon Chuan Low2

  • 1Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543.

Scientific Reports
|January 24, 2014
PubMed

Insights

Researchers elucidated the active site inhibition mechanism of human kidney-type glutaminase (KGA), a key enzyme in cancer metabolism. Understanding this mechanism using 6-diazo-5-oxo-L-norleucine (DON) aids in developing novel KGA inhibitors for cancer therapy.

Area of Science:

  • Biochemistry
  • Enzymology
  • Cancer Biology

Background:

  • Glutaminase drives cancer cell proliferation via glutaminolysis.
  • Human kidney-type glutaminase (KGA) is a promising cancer drug target due to its upregulation in tumors.

Purpose of the Study:

  • To elucidate the active site inhibition mechanism of KGA.
  • To provide structural insights for developing KGA inhibitors.

Main Methods:

  • X-ray crystallography of the catalytic domain of KGA (cKGA) in complex with 6-diazo-5-oxo-L-norleucine (DON).
  • Site-directed mutagenesis to confirm residue function.

Main Results:

  • Determined the crystal structure of cKGA complexed with DON, a glutamine analog.
  • DON covalently binds to Ser286, forming an enzyme-inhibitor complex.
  • Identified key interacting residues (Tyr249, Asn335, Glu381, Asn388, Tyr414, Tyr466, Val484) essential for KGA activity.

Conclusions:

  • The study reveals the covalent active site inhibition mechanism of KGA by DON.
  • Structural and mutational data provide a foundation for designing targeted KGA inhibitors for cancer therapy.

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