Feb 6, 2020 · In our structure, IgM-Cμ4 forms a dimer within each Fcμ monomer (fig. S4A). The IgM-Cμ4 dimer here highly resembles the dimers formed by IgA-Cα3, IgG-Cγ3, and IgE-Cε4, but is remarkably distinct from the “parallel” dimer observed in the …

Immunoglobulin M (IgM) is the largest of several isotypes of antibodies (also known as immunoglobulin) that are produced by vertebrates. IgM is the first antibody to appear in the response to initial exposure to an antigen; [1][2] causing it to …

In contrast, immunoglobulin A (IgA) and immunoglobulin M (IgM) are usually assembled into dimers or pentamers with the contribution of joining (J)-chains, which bind to the secretory component (SC) of the polymeric Ig receptor (pIgR) and are transported to the mucosal surface.

Oct 14, 2019 · IgG has the highest opsonization and neutralization activities; IgM is the first antibody transiently increased upon antigen invasion; IgA is expressed in mucosal tissues; IgE is involved in allergy whereas IgD functions as an antigen receptor on activated B cells.

Based on small angle X-ray scattering data, we present a model of the ring-shaped Cµ4 structure, which reveals the principles of IgM oligomerization. Keywords: antibody oligomerization, hybrid approach, dimer interfaces.

The J chain regulates the multimerization of IgM and IgA in mammals. When expressed in cells, it favors the formation of a pentameric IgM and an IgA dimer. IgM pentamers are most commonly found with a single J chain, but some studies have seen as many as 4 J chains associated to a single IgM pentamer.

Oct 23, 2022 · Here, we use cryo-EM to image the structure of the human full-length IgM pentamer, revealing antigen binding domains flexibly attached to the asymmetric and rigid core formed by the Cμ4 and Cμ3...

Jun 3, 2013 · In this work we used X-ray crystallography and NMR spectroscopy to determine the atomic structures of the constant IgM Fc domains (Cµ2, Cµ3, and Cµ4) and to address their roles in IgM oligomerization. Although the isolated domains share the typical Ig fold, they differ substantially in dimerization properties and quaternary contacts.

Nov 6, 2021 · In contrast, immunoglobulin A (IgA) and immunoglobulin M (IgM) are usually assembled into dimers or pentamers with the contribution of joining (J)-chains, which bind to the secretory component (SC) of the polymeric Ig receptor (pIgR) and are transported to …

Only IgA and IgM can polymerize. The formation of IgA dimers and IgM pentamers is mediated by the joining chain (J chain), while IgM hexamers can be formed in the absence of J chain. Polymerized IgA, and to a lesser extent IgM, protect the mucosal surfaces from infection.