The primary structure of the basic isoform of Acanthamoeba profilin

Abstract

Acanthamoeba profilin‐II [Kaiser, D. A., Sato, M., Ebert, R. F. and Pollard, T. D. (1986) J. Cell. Biol. 102, 221–226] was digested with trypsin or cleaved by 2‐(2‐nitrophenylsulphenyl)‐3‐methyl‐3‐bromoindolenine. The tryptic peptides were purified by reversed‐phase‐high‐performance liquid chromatography and completely sequenced using automated gas‐phase sequence analysis. The complete profilin‐II sequence was deduced by ordering the tryptic peptides using the sequence information of the tryptophan‐cleavage products. Acanthamoeha profilin‐II was found to be homologous to the previously determined profilin‐I sequence [Ampe, C., Vandekerckhove, J., Brenner, L., Tobacman, L. and Korn, E. D. (1985) J. Biol. Chem. 260, 834–8401. Like profilin‐I, profilin‐II consists of 125 amino acids, has a blocked NH2 terminus and a trimethyllysine residue at position 103. Profilin‐II differs in at least 21 positions from one of the profilin‐I isoforms. The amino acid exchanges are mainly concentrated in the middle part of the sequence. Profilin‐II contains two more basic residues than profilin‐I, which explains its higher isoelectric point. Copyright © 1988, Wiley Blackwell. All rights reserved