Title: Molecular Evolution of the C-terminal Cytoplasmic Domain of a Superfamily of Bacterial Receptors Involved in Taxis
Abstract: Twenty-nine proteins from 16 different species of prokaryotes revealed an extensive sequence homology with the cytoplasmic domain of theEscherichia coliaspartate receptor. The high percentage of identity indicated that they constitute a superfamily of proteins. A consensus secondary structure consisting mostly of α-helices was predicted. The occurrence of a seven-residue repeat (a-b-c-d-e-f-g), in which both theaanddresidues were hydrophobic with few exceptions, provided additional evidence for a conserved α-helical conformation. Sequence alignments, together with the predicted secondary structure, led to identification of the boundaries for the functional units constituting the cytoplasmic domain. Putative methylation sites were assigned for all the members of this superfamily. These proteins could be grouped into three classes based on the presence of 14-residue insertion/deletion regions found within both the signalling and the methylation functional units of the cytoplasmic domain. The gene coding for the C-terminal cytoplasmic domain of these proteins apparently evolved through gene duplication from a common ancestor in which the four original 14-residue insertion/deletion regions were deleted two by two during evolution.
Publication Year: 1996
Publication Date: 1996-08-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 169
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