User:Nathan Roy: Difference between revisions

Line 1:

[[User:Nathan Roy/Sandbox 1]]I am a graduate student at the University of Vermont, studying the dynamics of HIV-1 cell to cell transmission and HIV-1 induced syncytia formation. Our wonderful professor, Dr. Steven Everse, has commissioned us (his students from his BioChem 351 course) to create a page describing the structure of a protein that interests us. I have chosen the HIV-1 gag protein, and more specifically, the MA and CA domains.

The HIV-1 Gag protein is the major structural protein required for virus assembly. It is synthesized as a polyprotein in the cytosol of an infected cell, and contains four functional segments; MA, CA (NTD and CTD), NC, and p6. The NC region is flanked by two "spacer" segments, denoted SP1 and SP2. The polyprotein is all alpha helical, except the NC region, which is composed of two RNA interacting zinc knuckle domains. Gag is often referred to as an "assembly machine", because expression of Gag alone is sufficient to produce budding virus-like particles (VLP's), due to multimerization of roughly 2000 Gag molecules per virion. Here, we will take a closer look at the MA and CA domains, and how the structural components of these domains aid in the assembly of virus particles. <applet load='~~2h3f~~' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' />

The HIV-1 Gag protein is the major structural protein required for virus assembly. It is synthesized as a polyprotein in the cytosol of an infected cell, and contains four functional segments; MA, CA (NTD and CTD), NC, and p6. The NC region is flanked by two "spacer" segments, denoted SP1 and SP2. The polyprotein is all alpha helical, except the NC region, which is composed of two RNA interacting zinc knuckle domains. Gag is often referred to as an "assembly machine", because expression of Gag alone is sufficient to produce budding virus-like particles (VLP's), due to multimerization of roughly 2000 Gag molecules per virion. Here, we will take a closer look at the MA and CA domains, and how the structural components of these domains aid in the assembly of virus particles. <applet load='2H3F_mono1.pdb' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' />

Line 7:

When MA is not bound to PI(4,5)P2 (Figure 1), notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12 '''INSERT SCENE SHOWING RESIDUES''' (Because this is an NMR structure, it may be beneficial to look at only 1 of the 20 models). In this PI(4,5)P2 unbound structure, the myristyl group is sequestered in the pocket of helix 1 created by Leu 8 and Glu 12. Upon binding of PI(4,5)P2 to the hydrophobic groove created by helix 2, a type 2 beta turn, and helix 5, a slight conformational switch occurs in helix 1 (Figure 2), <applet load='~~2h3z~~' size='300' frame='true' align='left' caption='FIGURE 2. MA bound to PI(4,5)P2' /> causing a change in the alignment of Leu 8 and Glu 12, ejecting the myristyl group from it's sequestered state. '''INSERT SCENE SHOWING RESIDUES''' This structural switch allows membrane anchoring to be directly coupled to proper membrane localization of Gag, and thus efficient particle release.

When MA is not bound to PI(4,5)P2 (Figure 1), notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12 '''INSERT SCENE SHOWING RESIDUES''' (Because this is an NMR structure, it may be beneficial to look at only 1 of the 20 models). In this PI(4,5)P2 unbound structure, the myristyl group is sequestered in the pocket of helix 1 created by Leu 8 and Glu 12. Upon binding of PI(4,5)P2 to the hydrophobic groove created by helix 2, a type 2 beta turn, and helix 5, a slight conformational switch occurs in helix 1 (Figure 2), <applet load='2H3Z_mono1.pdb' size='300' frame='true' align='left' caption='FIGURE 2. MA bound to PI(4,5)P2' /> causing a change in the alignment of Leu 8 and Glu 12, ejecting the myristyl group from it's sequestered state. '''INSERT SCENE SHOWING RESIDUES''' This structural switch allows membrane anchoring to be directly coupled to proper membrane localization of Gag, and thus efficient particle release.

User:Nathan Roy: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 1: / Line 1: @@
 [[User:Nathan Roy/Sandbox 1]]I am a graduate student at the University of Vermont, studying the dynamics of HIV-1 cell to cell transmission and HIV-1 induced syncytia formation. Our wonderful professor, Dr. Steven Everse, has commissioned us (his students from his BioChem 351 course) to create a page describing the structure of a protein that interests us. I have chosen the HIV-1 gag protein, and more specifically, the MA and CA domains.
-The HIV-1 Gag protein is the major structural protein required for virus assembly. It is synthesized as a polyprotein in the cytosol of an infected cell, and contains four functional segments; MA, CA (NTD and CTD), NC, and p6. The NC region is flanked by two "spacer" segments, denoted SP1 and SP2. The polyprotein is all alpha helical, except the NC region, which is composed of two RNA interacting zinc knuckle domains. Gag is often referred to as an "assembly machine", because expression of Gag alone is sufficient to produce budding virus-like particles (VLP's), due to multimerization of roughly 2000 Gag molecules per virion. Here, we will take a closer look at the MA and CA domains, and how the structural components of these domains aid in the assembly of virus particles. <applet load='2h3f' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' />
+The HIV-1 Gag protein is the major structural protein required for virus assembly. It is synthesized as a polyprotein in the cytosol of an infected cell, and contains four functional segments; MA, CA (NTD and CTD), NC, and p6. The NC region is flanked by two "spacer" segments, denoted SP1 and SP2. The polyprotein is all alpha helical, except the NC region, which is composed of two RNA interacting zinc knuckle domains. Gag is often referred to as an "assembly machine", because expression of Gag alone is sufficient to produce budding virus-like particles (VLP's), due to multimerization of roughly 2000 Gag molecules per virion. Here, we will take a closer look at the MA and CA domains, and how the structural components of these domains aid in the assembly of virus particles. <applet load='2H3F_mono1.pdb' size='300' frame='true' align='right' caption=' FIGURE 1. MA unbound to PI(4,5)P2' />
@@ Line 7: / Line 7: @@
-When MA is not bound to PI(4,5)P2 (Figure 1), notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12 '''INSERT SCENE SHOWING RESIDUES''' (Because this is an NMR structure, it may be beneficial to look at only 1 of the 20 models). In this PI(4,5)P2 unbound structure, the myristyl group is sequestered in the pocket of helix 1 created by Leu 8 and Glu 12. Upon binding of PI(4,5)P2 to the hydrophobic groove created by helix 2, a type 2 beta turn, and helix 5, a slight conformational switch occurs in helix 1 (Figure 2), <applet load='2h3z' size='300' frame='true' align='left' caption='FIGURE 2. MA bound to PI(4,5)P2' /> causing a change in the alignment of Leu 8 and Glu 12, ejecting the myristyl group from it's sequestered state. '''INSERT SCENE SHOWING RESIDUES''' This structural switch allows membrane anchoring to be directly coupled to proper membrane localization of Gag, and thus efficient particle release.
+When MA is not bound to PI(4,5)P2 (Figure 1), notice the alignment of helix 1, and more precisely, the orientation of Leu 8 and Glu 12 '''INSERT SCENE SHOWING RESIDUES''' (Because this is an NMR structure, it may be beneficial to look at only 1 of the 20 models). In this PI(4,5)P2 unbound structure, the myristyl group is sequestered in the pocket of helix 1 created by Leu 8 and Glu 12. Upon binding of PI(4,5)P2 to the hydrophobic groove created by helix 2, a type 2 beta turn, and helix 5, a slight conformational switch occurs in helix 1 (Figure 2), <applet load='2H3Z_mono1.pdb' size='300' frame='true' align='left' caption='FIGURE 2. MA bound to PI(4,5)P2' /> causing a change in the alignment of Leu 8 and Glu 12, ejecting the myristyl group from it's sequestered state. '''INSERT SCENE SHOWING RESIDUES''' This structural switch allows membrane anchoring to be directly coupled to proper membrane localization of Gag, and thus efficient particle release.