2asr
From Proteopedia
THE THREE-DIMENSIONAL STRUCTURE OF THE ASPARTATE RECEPTOR FROM ESCHERICHIA COLI
Structural highlights
Function[MCP2_ECOLI] Receptor for the attractant L-aspartate and related amino and dicarboxylic acids. Tar also mediates taxis to the attractant maltose via an interaction with the periplasmic maltose binding protein. Tar mediates taxis away from the repellents cobalt and nickel. Chemotactic-signal transducers respond to changes in the concentration of attractants and repellents in the environment, transduce a signal from the outside to the inside of the cell, and facilitate sensory adaptation through the variation of the level of methylation. Attractants increase the level of methylation while repellents decrease the level of methylation, the methyl groups are added by the methyltransferase CheR and removed by the methylesterase CheB. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of the periplasmic domain of the aspartate receptor from Escherichia coli has been solved and refined to an R-factor of 0.203 at 2.3 A, resolution. The dimeric protein is largely helical, with four helices from each monomer forming a four-helix bundle. The dimer interface is constructed from four helices, two from each subunit, also packed together in a four-helix bundle arrangement. A sulfate ion occupies the aspartate-binding site. All hydrogen bonds made to aspartate are substituted by direct or water-mediated hydrogen bonds to the sulfate. Comparison of the Escherichia coli aspartate-receptor structure with that of Salmonella typhimurium [Milburn, Prive, Milligan, Scott, Yeh, Jancarik, Koshland & Kim (1991). Science, 254, 1342-1347; Scott, Milligan, Milburn, Prive, Yeh, Koshland & Kim (1993). J. Mol. Biol. 232, 555-573] reveals strong conservation in the structure of the monomer, but more divergence in the orientation of the subunits with respect to one another. Mutations that render the Escherichia coli receptor incapable of responding to maltose are either located in spatially conserved sites or in regions of the structures that have high temperature factors and are therefore likely to be quite flexible. The inability of the receptor from Salmonella typhimurium to respond to maltose may, therefore, be because of differences in amino acids located on the binding surface rather than structural differences. The three-dimensional structure of the aspartate receptor from Escherichia coli.,Bowie JU, Pakula AA, Simon MI Acta Crystallogr D Biol Crystallogr. 1995 Mar 1;51(Pt 2):145-54. PMID:15299315[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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