Mammalian sperm tubulin: an exceptionally large number of variants based on several posttranslational modifications.
Extraction of demembranated bull sperm flagella by SDS was used to maximize tubulin solubilization. The alpha- and beta-tubulin separated by SDS-PAGE were treated with endoproteinases LysC and AspN, respectively. Carboxy-terminal fragments were isolated by Mono Q chromatography and reversed-phase HPLC. Automated sequencing and mass spectrometry revealed an astonishingly high number of tubulin variants. Many variants were due to polyglutamylation and in particular to polyglycylation. The number of side-chain glycyl residues ranged from 0 to 28 in alpha and 0 to 15 in beta. Corresponding values for side-chain glutamyl residues were 0-6 in alpha and 0-3 in beta. Additional alpha variability was based on carboxy-terminal detyrosination and partial loss of the penultimate glutamate. A major glycylation site in alpha- and beta-tubulin was mapped. Some variants seem to display both glycyl and glutamyl side chains.
Plessmann
U
U
Max Planck Institute for Biophysical Chemistry, Department of Biochemistry, Goettingen, Germany.
Weber
K
K
D000595:Amino Acid Sequence; D000818:Animals; D000837:Anion Exchange Resins; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D010450:Endopeptidases / Q000378:metabolism; D008297:Male; D008666:Metalloendopeptidases / Q000378:metabolism; D008969:Molecular Sequence Data; D010247:Paramecium; D011499:Protein Processing, Post-Translational; D012117:Resins, Synthetic; D012617:Sea Urchins; D017386:Sequence Homology, Amino Acid; D012967:Sodium Dodecyl Sulfate; D013094:Spermatozoa / Q000378:metabolism*; D014404:Tubulin / Q000032:analysis / Q000378:metabolism*
D000837:Anion Exchange Resins; D012117:Resins, Synthetic; D014404:Tubulin; D012967:Sodium Dodecyl Sulfate; C042855:Mono Q; D010450:Endopeptidases; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; C058921:endoproteinase Asp-N