Structure and activation mechanism of the human liver-type glutaminase GLS2

DOI: 10.1016/j.biochi.2021.03.009

Authors: Igor M. Ferreira (Brazilian Center for Research in Energy and Materials) , José Edwin N. Quesñay (Brazilian Center for Research in Energy and Materials; University of Sao Paulo) , Alliny C. S. Bastos (Brazilian Center for Research in Energy and Materials; University of Campinas (UNICAMP)) , Camila T. Rodrigues (University of Sao Paulo) , Melanie Vollmar (Structural Genomics Consortium, University of Oxford) , Tobias Krojer (Structural Genomics Consortium, University of Oxford) , Claire Strain-Damerell (Structural Genomics Consortium, University of Oxford; Diamond Light Source) , Nicola A. Burgess-Brown (Structural Genomics Consortium, University of Oxford) , Frank Von Delft (Structural Genomics Consortium, University of Oxford; Diamond Light Source; University of Johannesburg; Research Complex at Harwell) , Wyatt W. Yue (Structural Genomics Consortium, University of Oxford) , Sandra M G. Dias (Brazilian Center for Research in Energy and Materials) , Andre L. B. Ambrosio (Brazilian Center for Research in Energy and Materials; University of Sao Paulo)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochimie , VOL 185 , PAGES 96 - 104

State: Published (Approved)
Published: June 2021
Diamond Proposal Number(s): 8421

Abstract: Cancer cells exhibit an altered metabolic phenotype, consuming higher levels of the amino acid glutamine. This metabolic reprogramming depends on increased mitochondrial glutaminase activity to convert glutamine to glutamate, an essential precursor for bioenergetic and biosynthetic processes in cells. Mammals encode the kidney-type (GLS) and liver-type (GLS2) glutaminase isozymes. GLS is overexpressed in cancer and associated with enhanced malignancy. On the other hand, GLS2 is either a tumor suppressor or an oncogene, depending on the tumor type. The GLS structure and activation mechanism are well known, while the structural determinants for GLS2 activation remain elusive. Here, we describe the structure of the human glutaminase domain of GLS2, followed by the functional characterization of the residues critical for its activity. Increasing concentrations of GLS2 lead to tetramer stabilization, a process enhanced by phosphate. In GLS2, the so-called “lid loop” is in a rigid open conformation, which may be related to its higher affinity for phosphate and lower affinity for glutamine; hence, it has lower glutaminase activity than GLS. The lower affinity of GLS2 for glutamine is also related to its less electropositive catalytic site than GLS, as indicated by a Thr225Lys substitution within the catalytic site decreasing the GLS2 glutamine concentration corresponding to half-maximal velocity (K0.5). Finally, we show that the Lys253Ala substitution (corresponding to the Lys320Ala in the GLS “activation” loop, formerly known as the “gating” loop) renders a highly active protein in stable tetrameric form. We conclude that the “activation” loop, a known target for GLS inhibition, may also be a drug target for GLS2.

Journal Keywords: GlutaminaseLiver-type; Isozyme; Breast cancer; Metabolism; Crystal structure; Kinetics; Cooperativity

Diamond Keywords: Breast Cancer

Subject Areas: Biology and Bio-materials, Medicine


Instruments: I03-Macromolecular Crystallography

Added On: 30/03/2021 10:28

Documents:
1-s2.0-S0300908421000791-main.pdf

Discipline Tags:

Non-Communicable Diseases Health & Wellbeing Cancer Structural biology Drug Discovery Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)