Accessibility of the high-mannose glycans of glycoprotein gp120 from humanimmunodeficiency virus type 1 probed by in vitro interaction with mannose-binding lectins

The direct interaction of mannose-specific plant lectins with gp120 of HIV- 1 was studied by surface plasmon resonance. Inhibition experiments indicate d that exposed high mannose type glycans play a key role in the interaction . Most of the lectins specifically accommodate outer alpha 1,2-, alpha 1,3- , or alpha 1,6-linked di- or trimannosides, and especially legume lectins, also interact with the trimannoside core of the complex type glycans. The u nexpected affinity of some lectins towards gp120 presumably results from co nformational differences in their binding sites. These results demonstrate that mannose-specific plant lectins are powerful tools to study the accessi bility and elucidate the function of the gp120 glycans in the recognition a nd infection of the host cells by HIV-1. (C) 2000 Academic Press.