Crystal structures of the HIV-1 inhibitory cyanobacterial protein MVL free and bound to man3GlcNAc2: Structural basis for specificity and high-affinity binding to the core pentasaccharide from N-linked oligomannoside

David C. Williams, Jae Young Lee, Mengli Cai, Carole A. Bewley, G. Marius Clore

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

The cyanobacterial protein MVL inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations by binding to high mannose N-linked carbohydrate on the surface of the envelope glycoprotein gp120. Although a number of other carbohydrate-binding proteins have been shown to inhibit HIV-1 envelope-mediated cell fusion, the specificity of MVL is unique in that its minimal target comprises the Manα(1→6) Manβ(1→4)GlcNAcβ(1→4) GlcNAc tetrasaccharide core of oligomannosides. We have solved the crystal structures of MVL free and bound to the pentasaccharide Man 3GlcNAc2 at 1.9- and 1.8-Å resolution, respectively. MVL is a homodimer stabilized by an extensive intermolecular interface between monomers. Each monomer contains two structurally homologous domains with high sequence similarity connected by a short five-amino acid residue linker. Intriguingly, a water-filled channel is observed between the two monomers. Residual dipolar coupling measurements indicate that the structure of the MVL dimer in solution is identical to that in the crystal. Man 3GlcNAc2 binds to a preformed cleft at the distal end of each domain such that a total of four independent carbohydrate molecules associate with each homodimer. The binding cleft provides shape complementarity, including the presence of a deep hydrophobic hole that accommodates the N-acetyl methyl at the reducing end of the carbohydrate, and specificity arises from 7-8 intermolecular hydrogen bonds. The structures of MVL and the MVL-Man3GlcNAc2 complex further our understanding of the molecular basis of high affinity and specificity in protein-carbohydrate recognition.

Original languageEnglish
Pages (from-to)29269-29276
Number of pages8
JournalJournal of Biological Chemistry
Volume280
Issue number32
DOIs
StatePublished - 12 Aug 2005

Fingerprint

Dive into the research topics of 'Crystal structures of the HIV-1 inhibitory cyanobacterial protein MVL free and bound to man3GlcNAc2: Structural basis for specificity and high-affinity binding to the core pentasaccharide from N-linked oligomannoside'. Together they form a unique fingerprint.

Cite this