Complement Regulator-Acquiring Surface Protein: Difference between revisions

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== '''Structure''' ==
== '''Structure''' ==


In nature, BbCRASP-1 exists as a homodimer bound to the spirochete's surface <ref name="Cordes">PMID: 15711564</ref>. Researchers confirmed this by viewing the presence of pieces of the dimer in solution <ref name="Cordes">PMID: 15711564</ref>. They viewed the results through analytical ultracentrifugation and saw that dimeric crystals formed. If its dimeric state is threatened, BbCRASP-1 would not be able to function.  
In nature, BbCRASP-1 exists as a homodimer bound to the spirochete's surface <ref name="Cordes">PMID: 15711564</ref>. BbCRASP-1 needs to be dimerized in order to bind FH/FHL-1 proteins. If its dimeric state is threatened, BbCRASP-1 would not be able to function.  


=== '''Importance of the C-terminus''' ===
=== '''Importance of the C-terminus''' ===


Sequences of high conservation in the C-terminal regions of the protein’s monomers, <scene name='SB2013_L01gr6/C-terminus/1'>residues 241 to 250</scene> , were of interest as a potential binding site <ref name="Cordes">PMID: 15711564</ref>. Previous studies showed that deletion of these sites caused a complete inability of BbCRASP-1 to bind FH and FHL-1 regulators <ref name="Kraiczy">PMID: 14607842</ref>. The role of the C-terminus was determined by mutating <scene name='SB2013_L01gr6/Leucine_246/1'>leucine 246</scene> in this region of the dimer to aspartate <ref name="Cordes">PMID: 15711564</ref>. Both the C-terminally truncated and mutated BbCRASP-1 proteins lost their ability to dimerize, inhibiting them from binding to their host’s regulatory factors. It was then concluded that the C-terminus is a structurally sensitive region rather than a direct binding site <ref name="Cordes">PMID: 15711564</ref>. The C-terminus one monomer lies against the <scene name='SB2013_L01gr6/N-terminal_helix_ribbon/1'>N-terminal half of the E helix</scene> of the other and holds the <scene name='SB2013_L01gr6/Monomers_and_cterminus/1'>two monomers</scene> in place <ref name="Cordes">PMID: 15711564</ref>.
The C-terminus of BbCRASP-1 is a region crucial for its stability as a dimer. Previously,sequences of high conservation in the C-terminal regions of the protein’s monomers, <scene name='SB2013_L01gr6/C-terminus/1'>residues 241 to 250</scene> , were of interest as a potential binding site <ref name="Cordes">PMID: 15711564</ref>. Prior studies showed that deletion of these sites caused a complete inability of BbCRASP-1 to bind FH and FHL-1 regulators <ref name="Kraiczy">PMID: 14607842</ref>. The role of the C-terminus was determined by mutating <scene name='SB2013_L01gr6/Leucine_246/1'>leucine 246</scene> in this region of the dimer to aspartate <ref name="Cordes">PMID: 15711564</ref>. Both the C-terminally truncated and mutated BbCRASP-1 proteins lost their ability to dimerize, inhibiting them from binding to their host’s regulatory factors. It was then concluded that the C-terminus is a structurally sensitive region rather than a direct binding site <ref name="Cordes">PMID: 15711564</ref>. The C-terminus one monomer lies against the <scene name='SB2013_L01gr6/N-terminal_helix_ribbon/1'>N-terminal half of the E helix</scene> of the other and holds the <scene name='SB2013_L01gr6/Monomers_and_cterminus/1'>two monomers</scene> in place <ref name="Cordes">PMID: 15711564</ref>.


=== '''Other Potential Binding Sites''' ===
=== '''Other Potential Binding Sites''' ===
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