4W6V:
reference: Role of electrostatic interactions for ligand recognition and specificity of peptide transporters., Boggavarapu R, Jeckelmann JM, Harder D, Ucurum Z, Fotiadis D, BMC Biol. 2015 Aug 6;13(1):58. doi: 10.1186/s12915-015-0167-8. PMID: 26246134

This OCA Structure page
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