Sandbox Reserved 1785

From Proteopedia

(Difference between revisions)

Revision as of 11:47, 5 April 2023

This Sandbox is Reserved from February 27 through August 31, 2023 for use in the course CH462 Biochemistry II taught by R. Jeremy Johnson at the Butler University, Indianapolis, USA. This reservation includes Sandbox Reserved 1765 through Sandbox Reserved 1795.

To get started:

Click the edit this page tab at the top. Save the page after each step, then edit it again.
show the Scene authoring tools, create a molecular scene, and save it. Copy the green link into the page.
Add a description of your scene. Use the buttons above the wikitext box for bold, italics, links, headlines, etc.

More help: Help:Editing

Human B-cell Antigen Receptor: IgM BCR

1 Introduction
- 1.1 Significance and Background
- 1.2 History and Discovery
2 Structure
3 Relevance
- 3.1 Signal Transduction

Introduction

Significance and Background

History and Discovery

Structure

Transmembrane Region

The IgM BCR is tethered to B-cell membranes through the which is broken up into both extracellular and integral domains. IgM BCR assembly requires dimerization of the Ig alpha and Ig beta subunits which embed within the B-cell membrane. The is dimerized in both the integral region, with a hydrogen bond, and within the extracellular region with a . Although the mechanism of disulfide bridge formation is still unknown, it is believed that via N-linked glycosylation (NAGs, shown in green) of various asparagine residues in the extracellular region of both the alpha and Ig beta chains help to facilitate this process. Chaperon proteins remain bound to the alpha and beta subunits until both dimerizations occur at which point the rest of the BCR complex can be recruited.

After Ig alpha/Ig beta dimerization the transmembrane helices of the heavy chains can embed within the B-cell membrane as well. The side chains of this are primarily hydrophobic side chains that allow for interactions with the hydrophobic tails in the phospholipid bilayer. A total of 9 polar residues (picture that zooms in here??) between each of the heavy chains are included on the interior of the helix structure which interact with a few polar residues on the Ig alpha and Ig beta chains to hold the complex together. Additional interactions between the Ig alpha/Ig beta dimer and the heavy chains occur in the constant region.

Fc Region

Fab Region

Figure 1. Surface Representation of IgM Antibody Binding Pocket

The Fab region of the IgM antibody is still poorly resolved, thus the specific side chain interactions between the heavy and light chains have not been determined. This depiction of the shows how the 4 β-sandwiches fit together; heavy chain A and B of the Fab region form a complex with the rest of the molecule via interactions with the heavy A and B of the Fc region, before continuing down into the intracellular domain to interact with the transmembrane region. The light chains however are only connected to the complex by forming interactions with the heavy chains within the Fab region. Although the specific residues within the Fab region have yet to be identified, it is estimated that each β-sandwich contains one disulfide bridge with additional hydrogen bonds.

Relevance

Signal Transduction

Figure 2. IgM Antibody Signal Transduction following Antigen Binding

References

Student Contributors

Retrieved from "http://52.214.119.220/wiki/index.php/Sandbox_Reserved_1785"

@@ Line 27: / Line 27: @@
 <scene name='95/952713/Variable_region/1'>variable region</scene>
 [[Image:Igm_surface.png|300 px|left|thumb|Figure 1. Surface Representation of IgM Antibody Binding Pocket]]
-<scene name='95/952713/Heavy-light_chain_interface/1'>Heavy-Light Chain Interface</scene>
+The Fab region of the IgM antibody is still poorly resolved, thus the specific side chain interactions between the heavy and light chains have not been determined. This depiction of the <scene name='95/952713/Heavy-light_chain_interface/1'>heavy-light chain interface</scene> shows how the 4 β-sandwiches fit together; heavy chain A and B of the Fab region form a complex with the rest of the molecule via interactions with the heavy A and B of the Fc region, before continuing down into the intracellular domain to interact with the transmembrane region. The light chains however are only connected to the complex by forming interactions with the heavy chains within the Fab region. Although the specific residues within the Fab region have yet to be identified, it is estimated that each β-sandwich contains one disulfide bridge with additional hydrogen bonds.
 =='''Relevance'''==