Secondary structure of the promastigote surface protease of Leishmania

By Raman spectroscopic analysis we have determined the secondary structure of the promastigote surface protease, named PSP or gp63, of Leishmania major. It consist of nearly 50% antiparallel beta-strand, and less than 20% alpha-helix. These results are contrasted with the predominantly alpha-helical VSGs of the African trypanosomes and the alpha-helical metalloprotease thermolysin. The PSP of Leishmania thus represents a novel kind of membrane-anchored protease.