6DNB

Crystal structure of T110A:S256A mutant human Glutamate oxaloacetate transaminase 1 (GOT1)

Summary for 6DNB

• Entry DOI: 10.2210/pdb6dnb/pdb
• Descriptor: Aspartate aminotransferase, cytoplasmic, TETRAETHYLENE GLYCOL, GLYCEROL, ... (5 entities in total)
• Functional Keywords: aspartate aminotransferase, glutamate oxaloacetate transaminase 1, got1, plp, transferase
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 46809.77

Authors

Assar, Z.,Holt, M.C.,Stein, A.J.,Lairson, L.,Lyssiotis, C.A. (deposition date: 2018-06-06, release date: 2018-11-14, Last modification date: 2023-10-11)

Primary citation

Holt, M.C.,Assar, Z.,Beheshti Zavareh, R.,Lin, L.,Anglin, J.,Mashadova, O.,Haldar, D.,Mullarky, E.,Kremer, D.M.,Cantley, L.C.,Kimmelman, A.C.,Stein, A.J.,Lairson, L.L.,Lyssiotis, C.A.
Biochemical Characterization and Structure-Based Mutational Analysis Provide Insight into the Binding and Mechanism of Action of Novel Aspartate Aminotransferase Inhibitors.
Biochemistry, 57:6604-6614, 2018

PubMed Abstract: Pancreatic cancer cells are characterized by deregulated metabolic programs that facilitate growth and resistance to oxidative stress. Among these programs, pancreatic cancers preferentially utilize a metabolic pathway through the enzyme aspartate aminotransferase 1 [also known as glutamate oxaloacetate transaminase 1 (GOT1)] to support cellular redox homeostasis. As such, small molecule inhibitors that target GOT1 could serve as starting points for the development of new therapies for pancreatic cancer. We ran a high-throughput screen for inhibitors of GOT1 and identified a small molecule, iGOT1-01, with in vitro GOT1 inhibitor activity. Application in pancreatic cancer cells revealed metabolic and growth inhibitory activity reflecting a promiscuous inhibitory profile. We then performed an in silico docking analysis to study inhibitor-GOT1 interactions with iGOT1-01 analogues that possess improved solubility and potency properties. These results suggested that the GOT1 inhibitor competed for binding to the pyridoxal 5-phosphate (PLP) cofactor site of GOT1. To analyze how the GOT1 inhibitor bound to GOT1, a series of GOT1 mutant enzymes that abolished PLP binding were generated. Application of the mutants in X-ray crystallography and thermal shift assays again suggested but were unable to formally conclude that the GOT1 inhibitor bound to the PLP site. Mutational studies revealed the relationship between PLP binding and the thermal stability of GOT1 while highlighting the essential nature of several residues for GOT1 catalytic activity. Insight into the mode of action of GOT1 inhibitors may provide leads to the development of drugs that target redox balance in pancreatic cancer.

PubMed: 30365304
DOI: 10.1021/acs.biochem.8b00914

Experimental method

X-RAY DIFFRACTION (1.7 Å)