Related Experiment Video
Updated: Mar 6, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Crystal structures of the phosphorylation mimics of human cytosolic branched chain aminotransferase
Elizabeth S Dare1, Robert H Newman2, Myra E Conway3
1Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, NC, USA.
Abstract:
The phosphorylation sites of the human cytosolic Branched Chain Aminotransferase (hBCATc) mediated by mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated-kinase 2 (ERK2, also known as MAPK1) were mapped. The crystal structures of the phosphorylation mimics at T33 and T36 were determined. The modified transaminase activity of these variants was analyzed. Although there were no major conformational changes in the phosphorylation mimics of hBCAT, a regional conformational change at the interdomain loop was observed mainly in mutant T33E. Consistently, when the catalytic turnovers of the T33E and T36E mutants were comparable to the wild type of hBCATc, the KM dropped significantly compared to the wild type, indicating a shift of the substrate binding affinity in the mutants. Taken together, this indicated the phosphorylation of hBCATc by ERK2 is affecting the hBCATc's transaminase activity.
Related Concept Videos
ATP Synthase: Structure
Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
ATP Synthase: Mechanism

