User:Nathan Roy: Difference between revisions

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Once Gag is localized to discreet sites on the plasma membrane, multimerization of Gag takes place quite quickly , driven by the CA domain, and more specifically our focus here, the C-terminal domain of CA (CTD). There are four helices that contribute to the interaction of CA CTD with it's partner. A side-by-side interaction has been proposed (Figure 3), but many believe the forces involved in the side-by-side model are not great enough to account for the organization and structural stability of assembled Gag. Also, helix 1 of the CA CTD contains a very conserved region of residues within many retroviruses called the MHR (major homology region)<scene name='User:Nathan_Roy/Mhr_side-by-side/1'>MHR region</scene>. In the side-by-side model, the MHR is not responsible for the dimer organization, therefore a model of the CA CTD dimer in which the MHR is responsible for organization of the CA CTD dimers has been sought. By making a single deletion of the Ala 177 residue (which lies in the loop between helix 1 and helix 2), the CA CTD domain adopts a domain-swapped conformation,<applet load='2ont_dimer.pdb' size='300' frame='true' align='right' caption='FIGURE 4. Domain swapped CA CTD' /> in which the MHR of helix 1 is extended to contact helices 2,3, and 4 of the adjacent CA CTD domain (Figure 4)(<scene name='User:Nathan_Roy/Mhr_domain_swapped/1'>~~Show~~ MHR</scene>. This domain swapping allows for a tighter binging of the CA CTD domains, and a stronger, and more rigid viral capsid.

Once Gag is localized to discreet sites on the plasma membrane, multimerization of Gag takes place quite quickly , driven by the CA domain, and more specifically our focus here, the C-terminal domain of CA (CTD). There are four helices that contribute to the interaction of CA CTD with it's partner. A side-by-side interaction has been proposed (Figure 3), but many believe the forces involved in the side-by-side model are not great enough to account for the organization and structural stability of assembled Gag. Also, helix 1 of the CA CTD contains a very conserved region of residues within many retroviruses called the MHR (major homology region)<scene name='User:Nathan_Roy/Mhr_side-by-side/1'>MHR region</scene>. In the side-by-side model, the MHR is not responsible for the dimer organization, therefore a model of the CA CTD dimer in which the MHR is responsible for organization of the CA CTD dimers has been sought. By making a single deletion of the Ala 177 residue (which lies in the loop between helix 1 and helix 2), the CA CTD domain adopts a domain-swapped conformation,<applet load='2ont_dimer.pdb' size='300' frame='true' align='right' caption='FIGURE 4. Domain swapped CA CTD' /> in which the MHR of helix 1 is extended to contact helices 2,3, and 4 of the adjacent CA CTD domain (Figure 4)(<scene name='User:Nathan_Roy/Mhr_domain_swapped/1'>MHR region</scene>). This domain swapping allows for a tighter binging of the CA CTD domains, and a stronger, and more rigid viral capsid.

Revision as of 01:14, 22 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary ← Older edit		Revision as of 01:19, 22 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary Newer edit →
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	<applet load='1aum_dimer.pdb' size='300' frame='true' align='left' caption='FIGURE 3. Side-by-side structure of CA CTD' />		<applet load='1aum_dimer.pdb' size='300' frame='true' align='left' caption='FIGURE 3. Side-by-side structure of CA CTD' />
	Once Gag is localized to discreet sites on the plasma membrane, multimerization of Gag takes place quite quickly , driven by the CA domain, and more specifically our focus here, the C-terminal domain of CA (CTD). There are four helices that contribute to the interaction of CA CTD with it's partner. A side-by-side interaction has been proposed (Figure 3), but many believe the forces involved in the side-by-side model are not great enough to account for the organization and structural stability of assembled Gag. Also, helix 1 of the CA CTD contains a very conserved region of residues within many retroviruses called the MHR (major homology region)<scene name='User:Nathan_Roy/Mhr_side-by-side/1'>MHR region</scene>. In the side-by-side model, the MHR is not responsible for the dimer organization, therefore a model of the CA CTD dimer in which the MHR is responsible for organization of the CA CTD dimers has been sought. By making a single deletion of the Ala 177 residue (which lies in the loop between helix 1 and helix 2), the CA CTD domain adopts a domain-swapped conformation,<applet load='2ont_dimer.pdb' size='300' frame='true' align='right' caption='FIGURE 4. Domain swapped CA CTD' /> in which the MHR of helix 1 is extended to contact helices 2,3, and 4 of the adjacent CA CTD domain (Figure 4)(<scene name='User:Nathan_Roy/Mhr_domain_swapped/1'>~~Show~~ MHR</scene>. This domain swapping allows for a tighter binging of the CA CTD domains, and a stronger, and more rigid viral capsid.		Once Gag is localized to discreet sites on the plasma membrane, multimerization of Gag takes place quite quickly , driven by the CA domain, and more specifically our focus here, the C-terminal domain of CA (CTD). There are four helices that contribute to the interaction of CA CTD with it's partner. A side-by-side interaction has been proposed (Figure 3), but many believe the forces involved in the side-by-side model are not great enough to account for the organization and structural stability of assembled Gag. Also, helix 1 of the CA CTD contains a very conserved region of residues within many retroviruses called the MHR (major homology region)<scene name='User:Nathan_Roy/Mhr_side-by-side/1'>MHR region</scene>. In the side-by-side model, the MHR is not responsible for the dimer organization, therefore a model of the CA CTD dimer in which the MHR is responsible for organization of the CA CTD dimers has been sought. By making a single deletion of the Ala 177 residue (which lies in the loop between helix 1 and helix 2), the CA CTD domain adopts a domain-swapped conformation,<applet load='2ont_dimer.pdb' size='300' frame='true' align='right' caption='FIGURE 4. Domain swapped CA CTD' /> in which the MHR of helix 1 is extended to contact helices 2,3, and 4 of the adjacent CA CTD domain (Figure 4)(<scene name='User:Nathan_Roy/Mhr_domain_swapped/1'>MHR region</scene>). This domain swapping allows for a tighter binging of the CA CTD domains, and a stronger, and more rigid viral capsid.