User:Janice C. Telfer/Group B SRCR domains: Difference between revisions

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== Group B Scavenger Receptor Cysteine-Rich (SRCR) Domains ==
== Group B Scavenger Receptor Cysteine-Rich (SRCR) Domains ==


Members of the group B SRCR domain family include CD5, CD6, DMBT1, Spα, WC1, CD163A, CD163b, and CD163c-α. (reviewed in Sarrias, M.R. 2004 Crit. Rev. in Immunology, 24:1-38; Herzig,C.T. and C.L. Baldwin 2009 BMC Genomics 10:191; and Herzig,C.T. et al 2010 Evol. Biology 10:181.) Some of these (i.e. WC1 and CD163c-α) are multi-gene families.


<applet load='2ja4' size='300' frame='true' align='right' caption='Group B SRCR domain' />
<applet load='2ja4' size='300' frame='true' align='right' caption='Group B SRCR domain' />


Group B SRCR domains are characterized by 6-8 cysteines, with conserved spacing. Disulfide bonds are formed between cysteines 1 and 4, 2 and 7, 3 and 8, and 5 and 6. Cysteines 2 and/or 7 are missing in The crystal structure of the third SRCR domain of human CD5 has been solved, showing four disulfide bonds  
Group B SRCR domains are 100-110 amino acids long and are characterized by 6-8 cysteines, with conserved spacing. Disulfide bonds are formed between cysteines 1 and 4, 2 and 7, 3 and 8, and 5 and 6. Cysteines 2 and/or 7 are missing in some group B SRCR domains, resulting in the loss of one of the potential disulfide bonds. The crystal structure of the third SRCR domain of human CD5, which contains 8 cysteines, shows four disulfide bonds (Rodamilans, B. et. al. 2007 J. Biol Chem 282:12669-77 doi M611699200 [pii]10.1074/jbc.M611699200.)


<scene name='Sandbox_Reserved_101/Cd5iii/5'>HsCD5 group B SRCR domain 3 disulfide bonds</scene>
<scene name='Sandbox_Reserved_101/Cd5iii/5'>HsCD5 group B SRCR domain 3 disulfide bonds</scene>
Group B SRCR domains bind to both protein and non-petidic ligands. In the latter class of ligands are molecules found on bacteria, such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA), which suggests that group B SRCR proteins play a role in the host immune response to microorganisms. The group B SRCR domain family member WC1 appears to play an important role in the bovine response to the spirochaete Leptospira as a co-receptor whose tyrosine phosphorylation is required for optimal gamma delta T cell response.  There are approximately 15 different WC1 genes in the bovine genome 


<scene name='Sandbox_Reserved_101/Wc1-1a/3'>WC1-1 SRCR domain 1a (WC1.1+)</scene>
<scene name='Sandbox_Reserved_101/Wc1-1a/3'>WC1-1 SRCR domain 1a (WC1.1+)</scene>