Molecular cloning of the major surface antigen of leishmania.

The gene encoding gp63, the major surface glycoprotein of Leishmania promastigotes, was isolated from Leishmania major using a synthetic oligonucleotide probe based on the NH2-terminal protein sequence of purified gp63. DNA sequence analysis and the translated amino acid sequence indicate that gp63 is synthesized as precursor molecule having both an NH2-terminal preregion (signal peptide) and an adjacent proregion. This structure is consistent with the protease activity of gp63 since many other proteases are synthesized as precursor forms requiring processing for enzymatic activity. Hybridization studies demonstrated that there are multiple copies of the gp63 gene in the genome of L. major and other Leishmania species. The conservation of the coding sequence of gp63 amongst diverse species of Leishmania provides further support for the importance of gp63 during the life cycle of Leishmania.