Sensory transducers of E. coli are composed of discrete structural and functional domains

“Frozen” dynamic dimer model for transmembrane signaling in bacterial chemotaxis receptors

“…This model was initially conceived from the predicted secondary structures derived from the amino acid sequences of the receptors. The primary structures contain 2 highly hydrophobic regions, each of which could span the membrane thickness when rolled into an a-helix Krikos et al, 1983;Russo & Koshland, 1983;Bollinger et al, 1984). The model was also thought to be consistent with the finding that 1 aspartate molecule binds to each monomer of the aspartate receptor from S. typhimurium (Foster et al, 1985).…”

Three-Dimensional Structures of the Ligand-Binding Domain of the Bacterial Aspartate Receptor with and Without a Ligand

“…For one such class, of which the epi&mil growth factor (3), platelet-derived growth factor ( 4 ) , insulin (5b and low-density lipoprotein (6) receptors are typical, the proteins contain an extracellular ligand-binding domain, a cytoplasmic signaling domain, and a transmembrane domain composed of one or two transmembrane hydrophobic sequences. The aspartate receptor of chemotaxis falls in this last category ( 7 ) and is itself a member of a large family of bacterial protein receptors (8). The ligand-binding domain of the aspartate receptor has been crystallized in the presence and absence of aspartate.…”

Nucleotide sequence of dcrA, a Desulfovibrio vulgaris Hildenborough chemoreceptor gene, and its expression in Escherichia coli

“…The two domains of these methyl-accepting chemotaxis proteins (MCPs; Mr = 58,000 to 60,000) are connected by a single hydrophobic transmembrane helix of -24 residues. These structural features have been deduced from a limited number of nucleotide sequences of genes for MCPs from members of the family Enterobacteriaceae, primarily the Escherichia coli tap, tar, tsr, and trg genes (4,5,14) and the Salmonella typhimurium tar gene (26). There is good experimental evidence that MCPs function more generally in motile prokaryotes in transduction of outside chemical and physical signals to the flagellar motor.…”