Manabe R, Saito T, Kumazaki T, Sakaitani T, Nakata N, Ochiai H. Molecular cloning and the COOH-terminal processing of gp64, a putative cell-cell adhesion protein of the cellular slime mold Polysphondylium pallidum.
J Biol Chem 1994;
269:528-35. [PMID:
8276846]
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Abstract
The cellular slime mold Polysphondylium pallidum expresses a cell surface glycoprotein (referred to as gp64), which seems to be implicated in cell-cell adhesion. We identified a near full-length gp64 cDNA (1,104 base) upon screening a P. pallidum lambda gt11 library with a monoclonal antibody. The open reading frame encodes a protein of 320 amino acids with a molecular mass of 32,752 Da; the protein includes hydrophobic segments at both a NH2- and a COOH-terminal ends. By an Edman degradation analysis of S-pyridylethylated gp64 and its COOH-terminal peptide, it was found that the NH2- and COOH-terminal segments are both removed from the precursor protein of gp64. The COOH-terminal segment was isolated from a lysyl endopeptidase digest of gp64 by an affinity method. The COOH-terminal segment was identified at positions 266-279 in the primary sequence deduced from the cDNA sequence. The mature gp64 consisted of 279 amino acid residues and extremely rich in Cys residues (36 Cys/279 amino acids = 12.9%). Although there was already maximal accumulation of gp64 mRNA in vegetative cells, the protein reached a maximal level during aggregation stage, decreased, and then leveled off through the developmental cycle.
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