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'>MHR region</scene>). Keep in mind these are only models of Gag dimerization and subsequent multimerization, and that precise interactions that take place during Gag assembly are yet to be agreed upon.

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, yet mutations in the MHR region have a greater impact on ''in vivo'' Gag assembly than mutations in the residues responsible for structural stablility of the side-by-side model. This lead researchers to seek a domain swapped structure of the CA CTD. 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>). Keep in mind these are only models of Gag dimerization and subsequent multimerization, and that precise interactions that take place during Gag assembly are yet to be agreed upon.

User:Nathan Roy: Difference between revisions

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Revision as of 03:26, 23 April 2009 view source Nathan Roy (talk \| contribs) 76 edits No edit summary ← Older edit		Revision as of 03:33, 23 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'>MHR region</scene>). Keep in mind these are only models of Gag dimerization and subsequent multimerization, and that precise interactions that take place during Gag assembly are yet to be agreed upon.		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, yet mutations in the MHR region have a greater impact on ''in vivo'' Gag assembly than mutations in the residues responsible for structural stablility of the side-by-side model. This lead researchers to seek a domain swapped structure of the CA CTD. 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>). Keep in mind these are only models of Gag dimerization and subsequent multimerization, and that precise interactions that take place during Gag assembly are yet to be agreed upon.