2D4U:
reference: Ligand specificity determined by differentially arranged common ligand-binding residues in the bacterial amino acid chemoreceptors Tsr and Tar., Tajima H, Imada K, Sakuma M, Hattori F, Nara T, Kamo N, Homma M, Kawagishi I, J Biol Chem. 2011 Oct 6. PMID: 21979954

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