The primary structure of rabbit J chain, which occurs covalently bound to secretory IgA, was determined. J chain was isolated in its S-carboxymethylated form, in one step, by SDS/PAGE followed by electro-elution; 5 nmol of protein (approx. 75 micrograms), in all, was necessary for the determination of the complete sequence by the ‘shot-gun’ microsquencing technique; with the use of several site-specific endoproteinases, the various digests of S-carboxymethylated J chain were separated by micro-bore reverse-phase h.p.l.c. and the partial N-terminal sequences of all peptides were analysed. From the sequence alignment, gaps were filled by further extensive sequencing of the relevant overlapping fragments isolated from selected digests. Rabbit J chain comprises 136 amino acid residues, out of which eight are conserved cysteine residues, and is more closely similar to the human sequence (73.5% identify) than to the mouse sequence (68% identity). There is one unique glycosylation site at asparagine-48.
Research Article| November 01 1990
The amino acid sequence of rabbit J chain in secretory immunoglobulin A
G J Hughes;
Biochem J (1990) 271 (3): 641–647.
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G J Hughes, S Frutiger, N Paquet, J C Jaton; The amino acid sequence of rabbit J chain in secretory immunoglobulin A. Biochem J 1 November 1990; 271 (3): 641–647. doi: https://doi.org/10.1042/bj2710641
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