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Structural similarities between the aspartate receptor of bacterial chemotaxis and the trp repressor of E. coli Implications for transmembrane signaling
Author(s) -
Lynch Berkley A.,
Koshland Daniel E.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80891-j
Subject(s) - repressor , structural similarity , chemotaxis , receptor , tryptophan , transmembrane domain , ligand (biochemistry) , biochemistry , chemistry , protein subunit , stereochemistry , amino acid , biology , gene , transcription factor
A high resolution structure of the N‐terminal ligand‐binding domain of the aspartate receptor which mediates aspartate chemotaxis in Salmonella typhimurium has recently been reported. A least‐squares superposition of the α‐amino nitrogen, α‐carbon, β‐carbon, and α‐carboxylate carbon of the aspartate bound to the aspartate receptor onto the equivalent atoms in the tryptophan bound to the trp repressor provides evidence for similarity between key parts of the active sites that bind to the α‐amino and α‐carboxylates of the respective ligands. Because the N‐terminal domain of the aspartate receptor and the trp repressor also share other structural similarities, we hypothesize that the similarity between the aspartate receptor and the trp repressor derives from a similarity in ligand‐induced conformational changes at the active sites of these proteins. This hypothesis also implies that an important signaling event in the aspartate receptor occurs through tertiary conformational changes within a single subunit.