PMID: 27402833
Matei E, Basu R, Furey W, Shi J, Calnan C, Aiken C, Gronenborn AM
Structure and Glycan Binding of a New Cyanovirin-N Homolog.
J Biol Chem. 2016 Jul 7. pii: jbc.M116.740415.
The HIV-1 envelope glycoprotein gp120 is heavily glycosylated and bears numerous high-mannose sugars. These sugars can serve as targets for HIV-inactivating compounds, such as antibodies and lectins, which bind to the glycans and interfere with viral entry into the target cell. We determined the 1.6 A X-ray structure of Cyt-CVNH, a recently identified lectin from the cyanobacterium Cyanothece7424, and elucidated its glycan specificity by NMR. The Cyt-CVNH structure and glycan recognition profile are similar to those of other CVNH proteins, with each domain specifically binding to Mana(1-2)Mana units on the D1 and D3 arms of high-mannose glycans. However, in contrast to CV-N, no cross-linking and precipitation of the cross-linked species in solutions was observed upon Man-9 binding, allowing for the first time to investigate the interaction of Man-9 with a member of the CVNH family by NMR. HIV assays showed that Cyt-CVNH is able to inhibit HIV-1 with ~ 4-fold higher potency than CV-NP51G, a stabilized version of wild type CV-N. Therefore, Cyt-CVNH may qualify as a valuable lectin for potential microbicidal use.