The amino acid sequence of rabbit J chain in secretory immunoglobulin A.
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.
Hughes
G J
GJ
Department of Medical Biochemistry, University of Geneva Medical Center, Switzerland.
Frutiger
S
S
Paquet
N
N
Jaton
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000737:chemistry*; D007144:Immunoglobulin J-Chains / Q000737:chemistry* / Q000302:isolation & purification; D051379:Mice; D008832:Microchemistry / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D012967:Sodium Dodecyl Sulfate
D007071:Immunoglobulin A, Secretory; D007144:Immunoglobulin J-Chains; D010446:Peptide Fragments; D012967:Sodium Dodecyl Sulfate; D001216:Asparagine; D010447:Peptide Hydrolases