5GXB:
reference: Crystal structure of a LacY-nanobody complex in a periplasmic-open conformation., Jiang X, Smirnova I, Kasho V, Wu J, Hirata K, Ke M, Pardon E, Steyaert J, Yan N, Kaback HR, Proc Natl Acad Sci U S A. 2016 Nov 1;113(44):12420-12425. Epub 2016 Oct 19. PMID: 27791182

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