Crystallization of amino-terminal domains and domain fragments of variant surface glycoproteins from Trypanosoma brucei brucei.

Crystals were produced from variant surface glycoproteins (VSG) of Trypanosoma brucei brucei antigenic variants MITat 1.2, 1.6, and ILTat 1.22, 1.23, 1.24, 1.25, and 1.26. Purified VSGs had molecular weights from 60,000 to 68,000 on sodium dodecyl sulfate-polyacrylamide gels, whereas the crystals obtained were composed of polypeptides of approximate Mr 40,000-50,000. Amino-terminal amino acid sequences determined from the crystallized VSGs were identical to sequences obtained from the respective intact proteins, indicating that the crystals contained VSG amino-terminal fragments. Crystallization conditions and lattice dimensions of the crystals are given.