2QPQ:
reference: Structure-based mechanism of ligand binding for periplasmic solute-binding protein of the Bug family., Herrou J, Bompard C, Antoine R, Leroy A, Rucktooa P, Hot D, Huvent I, Locht C, Villeret V, Jacob-Dubuisson F, J Mol Biol. 2007 Nov 2;373(4):954-64. Epub 2007 Aug 19. PMID: 17870093

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