Solution structure of the lipophosphoglycan of Leishmania donovani

The three-dimensional solution structure of the repeating -PO4-6Gal beta 1-4Man alpha 1- disaccharide fragment of the lipophosphoglycan (LPG) derived from Leishmania donovani has been determined by use of a combination of homo- and heteronuclear NMR spin coupling constant measurements together with restrained molecular mechanical minimization and molecular dynamics simulations. The fragment exists with limited mobility in solution about the Gal beta 1-4Man linkages, whereas in contrast a variety of stable rotamers exist about the Man alpha 1-PO4-6Gal linkages. These rotamers define several major stable conformers in solution, which are discussed in terms of the proposed biological role of LPG.