Yale UniversityDepartment of Chemistry
12:00 PM Tuesday, June 25
Main Seminar Room, New York Structural Biology Center
Protein Tyrosine Phosphatases (PTPs) are important regulators in signaling pathways in all organisms by regulating phosphorylation levels. Although bacterial and eukaryotic PTPs have been well studied, archaeal PTPs have not been extensively investigated. Here we report the first NMR study of archaeal PTP, sulfolobous solfataricus protein tyrosine phosphatase (SsoPTP), to expand our understanding of the correlation between enzymatic catalysis, structure and motions compared to other PTPs. SsoPTP is the sole PTP in S.solfataricus and remains functional in a wide range of temperatures. We sought to understand which structural and dynamic factors enable function in SsoPTP. We have studied molecular interactions between SsoPTP and the product analog ligand, tungstate, by NMR chemical shift perturbation methods over a range of temperatures. At different temperatures, residues that are significantly perturbed are mostly located in the active site as expected, but are also found in distal regions. We have identified an unknown allosteric site. Further, we have probed the micro- to millisecond conformational motions of SsoPTP at atomic resolution utilizing NMR off-resonance R1ρ and CPMG experiments. We detect loop residues in the active site of SsoPTP are undergoing conformational exchange in the Apo and product bound state and speculate on their functional roles.