| First Author | Klaus T | Year | 2018 |
| Journal | Sci Rep | Volume | 8 |
| Issue | 1 | Pages | 519 |
| PubMed ID | 29323348 | Mgi Jnum | J:260156 |
| Mgi Id | MGI:6148565 | Doi | 10.1038/s41598-017-19003-4 |
| Citation | Klaus T, et al. (2018) Mouse Antibody of IgM Class is Prone to Non-Enzymatic Cleavage between CH1 and CH2 Domains. Sci Rep 8(1):519 |
| abstractText | IgM is a multivalent antibody which evolved as a first line defense of adaptive immunity. It consists of heavy and light chains assembled into a complex oligomer. In mouse serum there are two forms of IgM, a full-length and a truncated one. The latter contains mu'' chain, which lacks a variable region. Although mu'' chain was discovered many years ago, its origin has not yet been elucidated. Our results indicate that mu'' chain is generated from a full-length heavy chain by non-enzymatic cleavage of the protein backbone. The cleavage occurred specifically after Asn209 and is prevented by mutating this residue into any other amino acid. The process requires the presence of other proteins, preferentially with an acidic isoelectric point, and is facilitated by neutral or alkaline pH. This unique characteristic of the investigated phenomenon distinguishes it from other, already described, Asn-dependent protein reactions. A single IgM molecule is able to bind up to 12 epitopes via its antigen binding fragments (Fabs). The cleavage at Asn209 generates truncated IgM molecules and free Fabs, resulting in a reduced IgM valence and probably affecting IgM functionality in vivo. |
