Amino acid sequence of a mouse immunoglobulin mu chain.

Abstract

The complete amino acid sequence of the mouse ,g chain from the BALB/c myeloma tumor MOPC 104E is reported. The CA region contains four consecutive homology regions of approximately 110 residues and a COOH-terminal region of 19 residues. A comparison of this p chain from mouse with a complete ;& sequence from human (Ou) and a partial A chain sequence from dog (Moo) reveals a striking gradient of increasing homology from the NH2-terminal to the COOH-terminal portion of these It chains, with the former being the least and the latter the most highly conserved. heavy chains held together by a third type of polypeptide designated the J chain (9). It is not known whether the membrane-bound and secreted ,u chains have the same polypeptide structure. Finally, after the IgM molecule binds antigen, the C,4 domain activates the effector pathways of the complement system (10).In this paper we report the amino acid sequence of the secreted ,. chain derived from the mouse myeloma tumor MOPC 104E. The mouse ti chain is compared with a human ,u chain whose sequence has been completely determined (11) and a dog ,q chain whose sequence has been partially determined (12, 13). As previously observed when the human ,u sequence and the dog At partial sequence were compared, there is a striking gradient of sequence homology, with the COOH-terminal homology regions significantly more conserved than the NH2-terminal homology regions (12). Several structural features of the ,u chain are highly conserved, including the placement of disulfide bridges and the locations of tryptophan residues and carbohydrate moieties in the constant region. t To whom reprint requests should be addressed.

Primary structure of the immunoglobulin J chain from the mouse.

“…These include the carboxyl-terminal constant domains and the adjoining 19-residue tails that are unique to secreted tL and a chains and contain the penultimate cysteine residue through which polymerization is effected (1, 2). Kehry et al (30) have found that the carboxyl-terminal regions of ,u chains are considerably more conserved than the amino-terminal regions, and similar results have recently been obtained for a chains (31). The mouse and human data from these studies are presented in Table 1 The question then arises as to why the polymerization process has been maintained over the evolution of the immunoglobulins.…”

Biochemical Characterization of Human PC‐1, an Enzyme Possessing Alkaline Phosphodiesterase I and Nucleotide Pyrophosphatase Activities

“…There is precedent for such a possibility. Kehry et al [33,341 found that in the p chains of both human and mouse IgM, two out of five N-linked glycans remained in a high-mannose form in the mature protein. In the case of IgM, the position of these unprocessed high-mannose glycans was conserved between species [33, 341. The nonspecifically precipitated 80-kDa protein seen in Figs 5 and 6 was converted to a 70-kDa form at all time points after treatment with endoglycosidase H (Fig.…”

Sequence Determination of the Heavy-Chain Constant Region in Four Immunoglobulin Classes of Mongolian Gerbils (<i>Meriones unguiculatus</i>)

“…The four amino acid sequences show that Cys and Trp residues were the most frequently conserved out of all amino acids in mouse and rat Ig classes, respectively. Cys and Trp are suggested to play important roles in maintaining Ig structure [6]. In particular, Cys is essential for the formation of intrachain disulfide bonds or bridges and for the polymerization of IgM and IgA [14].…”