2n5t | pdb_00002n5t
Ensemble solution structure of the phosphoenolpyruvate-Enzyme I complex from the bacterial phosphotransferase system
Structural highlights
Function[PT1_ECOLI] General (non sugar-specific) component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS). This major carbohydrate active-transport system catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. Enzyme I transfers the phosphoryl group from phosphoenolpyruvate (PEP) to the phosphoryl carrier protein (HPr).[1] Publication Abstract from PubMedEnzyme I (EI) is the first component in the bacterial phosphotransferase system, a signal transduction pathway in which phosphoryl transfer through a series of bimolecular protein-protein interactions is coupled to sugar transport across the membrane. EI is a multidomain, 128-kDa homodimer that has been shown to exist in two conformational states related to one another by two large (50-90 degrees ) rigid body domain reorientations. The open conformation of apo EI allows phosphoryl transfer from His189 located in the N-terminal domain alpha/beta (EINalpha/beta) subdomain to the downstream protein partner bound to the EINalpha subdomain. The closed conformation, observed in a trapped phosphoryl transfer intermediate, brings the EINalpha/beta subdomain into close proximity to the C-terminal dimerization domain (EIC), thereby permitting in-line phosphoryl transfer from phosphoenolpyruvate (PEP) bound to EIC to His189. Here, we investigate the solution conformation of a complex of an active site mutant of EI (H189A) with PEP. Simulated annealing refinement driven simultaneously by solution small angle X-ray scattering and NMR residual dipolar coupling data demonstrates unambiguously that the EI(H189A)-PEP complex exists in a dynamic equilibrium between two approximately equally populated conformational states, one corresponding to the closed structure and the other to a partially closed species. The latter likely represents an intermediate in the open-to-closed transition. Dynamic equilibrium between closed and partially closed states of the bacterial Enzyme I unveiled by solution NMR and X-ray scattering.,Venditti V, Schwieters CD, Grishaev A, Clore GM Proc Natl Acad Sci U S A. 2015 Aug 24. pii: 201515366. PMID:26305976[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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