4fpd

Deprotonation of D96 in bacteriorhodopsin opens the proton uptake pathway

spinqualitylabelsall models 4fpd, resolution 2.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fpd is a 1 chain structure with sequence from Halobacterium salinarum NRC-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.65Å Ligands: CL, LI1, RET Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function BACR_HALSA Light-driven proton pump. Publication Abstract from PubMed Despite extensive investigation, the precise mechanism controlling the opening of the cytoplasmic proton uptake pathway in bacteriorhodopsin (bR) has remained a mystery. From an analysis of the X-ray structure of the D96G/F171C/F219L triple mutant of bR and 60 independent molecular dynamics simulations of bR photointermediates, we report that the deprotonation of D96, a key residue in proton transfer reactions, serves two roles that occur sequentially. First, D96 donates a proton to the Schiff base. Subsequently, the deprotonation of D96 serves to "unlatch" the cytoplasmic side. The latching function of D96 appears to be remarkably robust, functioning to open hydration channels in all photointermediate structures. These results suggest that the protonation state of D96 may be the critical biophysical cue controlling the opening and closing of the cytoplasmic half-channel in bR. We suspect that this protonation-switch mechanism could also be utilized in other proton pumps to minimize backflow and reinforce directionality. Deprotonation of d96 in bacteriorhodopsin opens the proton uptake pathway.,Wang T, Sessions AO, Lunde CS, Rouhani S, Glaeser RM, Duan Y, Facciotti MT Structure. 2013 Feb 5;21(2):290-7. doi: 10.1016/j.str.2012.12.018. PMID:23394942 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Bacteriorhodopsin 3D structures

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