OCCURRENCE, OVEREXPRESSION AND PARTIAL-PURIFICATION OF THE PROTEIN (MAJASTRIDIN) CORRESPONDING TO THE URF6 GENE OF THE RHODOBACTER-BLASTICUS ATP OPERON

Antibodies were produced against two antigenic peptides of a protein, which was named majastridin, corresponding to the URF6 gene of the Rho dobacter blasticus atp operon [Tybulewicz, V. L. J., Falk, G. & Walker , J. E. (1984) J. Mel. Biol. 179, 185-214]. A protein band of the expe cted size is labelled by immunoblotting in Western blots containing th e cytosolic fractions from Rb. blasticus and Parncoccus denitrificans but not from Escherichia coli or Rhodospirillum rubrum. Although the p rotein is present during the entire life cycle of a Rb. blasticus cult ure, it is most abundant early during the stationary phase. Plasmid co nstructs of the URF6 gene for overexpression in E. coli were made. The se constructs were designed to obtain proteins both with and without H is-tagging. In both cases, a protein product was visible in induced ce lls. The His-tagged protein was purified to 85% on a Ni column and, fu rther, to at least 95% by anion-exchange chromatography. By N-terminal sequencing of the His-tagged protein, its identity was confirmed.