1wat
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THE THREE-DIMENSIONAL STRUCTURE OF THE LIGAND-BINDING DOMAIN OF A WILD-TYPE BACTERIAL CHEMOTAXIS RECEPTOR
OverviewOverview
The three-dimensional structures of the ligand-binding domain of the, wild-type Salmonella typhimurium aspartate receptor have been determined, in the absence (apo) and presence of bound aspartate (complex) and, compared to a cross-linked mutant containing a cysteine at position 36, which does not change signaling behavior of the intact receptor. The, structures of the wild-type forms were determined in order to assess the, effects of cross-linking on the structure and its influence on, conformational changes upon ligand binding. As in the case of the, cross-linked mutant receptor, the non-cross-linked ligand-binding domain, is dimeric and is composed of 4-alpha-helical bundle monomer subunits, related by a crystallographic 2-fold axis in the unbound form and by a, non-crystallographic axis in the aspartate-bound form. A comparative study, between the non-cross-linked and cross-linked structures has led to the, following observations: 1) The long N-terminal helices of the individual, subunits in the cross-linked structures are bent toward each other to, accommodate the disulfide bond. 2) The rest of the subunit conformation is, very similar to that of the wild-type. 3) The intersubunit angle of the, cross-linked apo structure is larger by about 13 degrees when compared to, the wild-type apo structure. 4) The nature and magnitude of the, aspartate-induced conformational changes in the non-cross-linked wild-type, structures are very similar to those of the cross-linked structures.
About this StructureAbout this Structure
1WAT is a Single protein structure of sequence from Salmonella typhimurium with ASP as ligand. Full crystallographic information is available from OCA.
ReferenceReference
The three-dimensional structure of the ligand-binding domain of a wild-type bacterial chemotaxis receptor. Structural comparison to the cross-linked mutant forms and conformational changes upon ligand binding., Yeh JI, Biemann HP, Pandit J, Koshland DE, Kim SH, J Biol Chem. 1993 May 5;268(13):9787-92. PMID:8486661
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