POSTTRANSLATIONAL MODIFICATIONS OF TRICHOMONAD TUBULINS - IDENTIFICATION OF MULTIPLE GLUTAMYLATION SITES

The alpha- and beta-tubulins present in cytoskeletons of Tritrichomona s mobilensis are extensively glutamylated. Automated sequencing and ma ss spectrometry of the carboxyterminal peptides identifies 4 glutamyla tion sites in alpha- and 2 sites in beta-tubulin. They are marked by a sterisks in the terminal sequences GDEE*E''E*DDG (alpha) and EGE*E''D EEAEA (beta), This is the first report that tubulin glutamylation can occur at multiple sites., Although T. mobilensis has four flagellae th e tubulins lack polyglycylation. Thus glycylation is not necessary for formation or function of axonemal microtubules. alpha-Tubulin is comp letely acetylated at lysine 40 and shows no tyrosine cycle. Peptide se quences establish tw distinct beta-tubulins. (C) 1998 Federation of Eu ropean Biochemical Societies.