cDNA and deduced primary structure of rat protein B23, a nucleolar protein containing highly conserved sequences.

摘要: Abstract Protein B23 (Mr/pI = 38,000/5.1) is a major RNA-associated nucleolar phosphoprotein which contains highly acidic segments and has high affinity for silver ions. Using synthetic oligonucleotides as probes cloned cDNAs encoding protein were isolated characterized. One of the cDNAs, obtained from rat brain library, contained an insert 1232 base pairs DNA polypeptide 292 amino acid residues. Segments sequence confirmed by partial sequencing CNBr fragments hepatoma B23. The methionine-rich amino-terminal two in center sequence. first segment, 11 13 residues are acidic, begins at residue 120 phosphorylation site. In second segment (residues 159-187) there four copies Asp-Asp-Glu, all but 29 have side chains. When was compared with available sequences other species degree conservation found; 77-residue carboxyl-terminal identical that human (Chan, P. K., Chan, W.-Y., Yung, B. Y. M., Cook, R. G., Aldrich, M. B., Ku, D., Goldknopf, I. L., Busch, H. (1986) J. Biol. Chem. 261, 14335-24341), about 63% when N038 Xenopus laevis (Schmidt-Zachmann, S., Hugle-Dorr, Franke, W. (1987) EMBO 6, 1881-1890). Except presence regions no significant similarities found C23 (nucleolin), protein.