title: Expression of the recombinant human immunoglobulin J chain in Escherichia coli.
abstract: Selective transport of polymeric (p) immunoglobulins (Ig) of IgA and IgM isotypes into external secretions by pIg receptor-mediated mechanism depends on the incorporation of joining (J) chain into the polymers. Until now, availability of a free J chain for immunological and biophysical studies has been limited to preparations of denatured J chain forms with moderate yield. Here we report that a recombinant J chain (rJ) can be over-expressed as a soluble fusion protein with thioredoxin using a modified vector pET32 in Escherichia coli. An intact J chain was released by digestion with IgA1 protease from Neisseria gonorrhoeae and isolated in a good yield with immunological and biochemical properties similar to those of J chain obtained by chemical cleavage from pIgA.
authors.affiliation: Center for Macromolecular Crystallography, University of Alabama at Birmingham, AL 35294, USA.
authors.forename: J
authors.initials: J
authors.lastname: Symersky
authors.forename: J
authors.initials: J
authors.lastname: Novak
authors.forename: D T
authors.initials: DT
authors.lastname: McPherson
authors.forename: L
authors.initials: L
authors.lastname: DeLucas
authors.forename: J
authors.initials: J
authors.lastname: Mestecky
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007070:Immunoglobulin A; D007144:Immunoglobulin J-Chains / Q000096:biosynthesis* / Q000235:genetics; D007075:Immunoglobulin M; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D012697:Serine Endopeptidases / Q000378:metabolism; D013879:Thioredoxins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D007070:Immunoglobulin A; D007144:Immunoglobulin J-Chains; D007075:Immunoglobulin M; D011993:Recombinant Fusion Proteins; C034639:polymeric IgA; C024242:polymeric IgM; D013879:Thioredoxins; D012697:Serine Endopeptidases; C021433:IgA-specific serine endopeptidase