2mwh
NMR solution structure of ligand-free OAA
Structural highlights
FunctionLEC1_PLAAG Lectin specific for high mannose N-glycans, recognizes the branched moiety of these glycans. Does not recognize other types of N-glycans or monosaccharides. Agglutinates trypsin-treated rabbit erythrocytes. Does not require divalent cations for activity. Inhibits HIV replication in MT4 cells with an EC(50) of 45 nM. Binds to the HIV envelope glycoprotein gp120.[1] [2] Publication Abstract from PubMedLectins from different sources have been shown to interfere with HIV infection by binding to the sugars of viral-envelope glycoproteins. Three-dimensional atomic structures of a number of HIV-inactivating lectins have been determined, both as free proteins and in glycan-bound forms. However, details on the mechanism of recognition and binding to sugars are elusive. Herein we focus on the anti-HIV lectin OAA from Oscillatoria agardhii: We show that in the absence of sugars in solution, both the sugar-free and sugar-bound protein conformations that were observed in the X-ray crystal structures exist as conformational substates. Our results suggest that glycan recognition occurs by conformational selection within the ground state; this model differs from the popular "excited-state" model. Our findings provide further insight into molecular recognition of the major receptor on the HIV virus by OAA. These details can potentially be used for the optimization and/or development of preventive anti-HIV therapeutics. Sampling of Glycan-Bound Conformers by the Anti-HIV Lectin Oscillatoria agardhii agglutinin in the Absence of Sugar.,Carneiro MG, Koharudin LM, Ban D, Sabo TM, Trigo-Mourino P, Mazur A, Griesinger C, Gronenborn AM, Lee D Angew Chem Int Ed Engl. 2015 Apr 14. doi: 10.1002/anie.201500213. PMID:25873445[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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