Sandbox Reserved 1785: Difference between revisions
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The Fab region of the antibody is where antigen recognition occurs upon binding (Figure 1). On each arm is one heavy ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) and one light (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) chain, both containing domains identical to their respective counterparts. Repeats of β-sandwiches form the [https://en.wikipedia.org/wiki/Antibody constant and variable domains] within the Fab region as antigen recognition occurs at the variable domain while the constant domain connects it to the rest of the IgM complex. Because the Fab region of IgM is poorly resolved, a structural analysis of an HIV neutralizing antibody called VCR01 was performed to approximate where an antigen would bind to at the <scene name='95/952714/Variable_region/1'>variable region</scene>. <ref name="Zhou">PMID:20616231</ref> | The Fab region of the antibody is where antigen recognition occurs upon binding (Figure 1). On each arm is one heavy ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) and one light (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) chain, both containing domains identical to their respective counterparts. Repeats of β-sandwiches form the [https://en.wikipedia.org/wiki/Antibody constant and variable domains] within the Fab region as antigen recognition occurs at the variable domain while the constant domain connects it to the rest of the IgM complex. Because the Fab region of IgM is poorly resolved, a structural analysis of an HIV neutralizing antibody called VCR01 was performed to approximate where an antigen would bind to at the <scene name='95/952714/Variable_region/1'>variable region</scene>. <ref name="Zhou">PMID:20616231</ref> | ||
The IgM-BCR contains areas referred to as [https://en.wikipedia.org/wiki/Complementarity-determining_region complementary-determining regions](CDRs), which are where the antigen makes <scene name='95/952713/Antigen_antibody_contact/ | The IgM-BCR contains areas referred to as [https://en.wikipedia.org/wiki/Complementarity-determining_region complementary-determining regions](CDRs), which are where the antigen makes <scene name='95/952713/Antigen_antibody_contact/4'>contact</scene> with the antibody on the Fab domain. Figure 2 depicts this as a surface representation given that the specific residues within the antigen-binding motif are unknown. | ||
Due to the poor resolution of the Fab region, specific side chain interactions between the heavy ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) and light (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) chains have not been determined. It is estimated that each β-sandwich contains one disulfide bridge with additional hydrogen bonds. The <scene name='95/952713/Heavy-light_chain_interface/2'>heavy-light chain interface</scene> shows how the four heavy and light chain β-sandwiches fit together. The Fab region heavy chains attach to the Fc region heavy chains, before continuing down into the intracellular domain to interact with the <b><span class="text-brown">Igα</span></b>/<b><span class="text-orange">Igβ</span></b> subunits. The light chains (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) however are only connected to the heavy chains ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) within the Fab region, thus have no contact with the <b><span class="text-brown">Igα</span></b>/<b><span class="text-orange">Igβ</span></b> heterodimer. | Due to the poor resolution of the Fab region, specific side chain interactions between the heavy ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) and light (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) chains have not been determined. It is estimated that each β-sandwich contains one disulfide bridge with additional hydrogen bonds. The <scene name='95/952713/Heavy-light_chain_interface/2'>heavy-light chain interface</scene> shows how the four heavy and light chain β-sandwiches fit together. The Fab region heavy chains attach to the Fc region heavy chains, before continuing down into the intracellular domain to interact with the <b><span class="text-brown">Igα</span></b>/<b><span class="text-orange">Igβ</span></b> subunits. The light chains (<b><span class="text-purple">A</span></b>/<b><span class="text-cyan">B</span></b>) however are only connected to the heavy chains ('''{{Font color|violet|A}}'''/<b><span class="text-blue">B</span></b>) within the Fab region, thus have no contact with the <b><span class="text-brown">Igα</span></b>/<b><span class="text-orange">Igβ</span></b> heterodimer. | ||
