1b9f: Difference between revisions
New page: left|200px<br /> <applet load="1b9f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b9f, resolution 1.7Å" /> '''MOBILITY OF AN HIV-1... |
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[[Image:1b9f.gif|left|200px]]<br /> | [[Image:1b9f.gif|left|200px]]<br /><applet load="1b9f" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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caption="1b9f, resolution 1.7Å" /> | caption="1b9f, resolution 1.7Å" /> | ||
'''MOBILITY OF AN HIV-1 INTEGRASE ACTIVE SITE LOOP IS CORRELATED WITH CATALYTIC ACTIVITY'''<br /> | '''MOBILITY OF AN HIV-1 INTEGRASE ACTIVE SITE LOOP IS CORRELATED WITH CATALYTIC ACTIVITY'''<br /> | ||
==Overview== | ==Overview== | ||
Replication of HIV-1 requires the covalent integration of the viral cDNA | Replication of HIV-1 requires the covalent integration of the viral cDNA into the host chromosomal DNA directed by the virus-encoded integrase protein. Here we explore the importance of a protein surface loop near the integrase active site using protein engineering and X-ray crystallography. We have redetermined the structure of the integrase catalytic domain (residues 50-212) using an independent phase set at 1.7 A resolution. The structure extends helix alpha4 on its N-terminal side (residues 149-154), thus defining the position of the three conserved active site residues. Evident in this and in previous structures is a conformationally flexible loop composed of residues 141-148. To probe the role of flexibility in this loop, we replaced Gly 140 and Gly 149, residues that appear to act as conformational hinges, with Ala residues. X-ray structures of the catalytic domain mutants G149A and G140A/G149A show further rigidity of alpha4 and the adjoining loop. Activity assays in vitro revealed that these mutants are impaired in catalysis. The DNA binding affinity, however, is minimally affected by these mutants as assayed by UV cross-linking. We propose that the conformational flexibility of this active site loop is important for a postbinding catalytic step. | ||
==About this Structure== | ==About this Structure== | ||
1B9F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Viruses Viruses] with CAC and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/RNA-directed_DNA_polymerase RNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.49 2.7.7.49] Full crystallographic information is available from [http:// | 1B9F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Viruses Viruses] with <scene name='pdbligand=CAC:'>CAC</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/RNA-directed_DNA_polymerase RNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.49 2.7.7.49] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B9F OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Viruses]] | [[Category: Viruses]] | ||
[[Category: Bushman, F | [[Category: Bushman, F D.]] | ||
[[Category: Butler, S | [[Category: Butler, S L.]] | ||
[[Category: Choe, S.]] | [[Category: Choe, S.]] | ||
[[Category: Greenwald, J.]] | [[Category: Greenwald, J.]] | ||
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[[Category: dna integration]] | [[Category: dna integration]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:54 2008'' | ||
Revision as of 12:52, 21 February 2008
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MOBILITY OF AN HIV-1 INTEGRASE ACTIVE SITE LOOP IS CORRELATED WITH CATALYTIC ACTIVITY
OverviewOverview
Replication of HIV-1 requires the covalent integration of the viral cDNA into the host chromosomal DNA directed by the virus-encoded integrase protein. Here we explore the importance of a protein surface loop near the integrase active site using protein engineering and X-ray crystallography. We have redetermined the structure of the integrase catalytic domain (residues 50-212) using an independent phase set at 1.7 A resolution. The structure extends helix alpha4 on its N-terminal side (residues 149-154), thus defining the position of the three conserved active site residues. Evident in this and in previous structures is a conformationally flexible loop composed of residues 141-148. To probe the role of flexibility in this loop, we replaced Gly 140 and Gly 149, residues that appear to act as conformational hinges, with Ala residues. X-ray structures of the catalytic domain mutants G149A and G140A/G149A show further rigidity of alpha4 and the adjoining loop. Activity assays in vitro revealed that these mutants are impaired in catalysis. The DNA binding affinity, however, is minimally affected by these mutants as assayed by UV cross-linking. We propose that the conformational flexibility of this active site loop is important for a postbinding catalytic step.
About this StructureAbout this Structure
1B9F is a Single protein structure of sequence from Viruses with and as ligands. Active as RNA-directed DNA polymerase, with EC number 2.7.7.49 Full crystallographic information is available from OCA.
ReferenceReference
The mobility of an HIV-1 integrase active site loop is correlated with catalytic activity., Greenwald J, Le V, Butler SL, Bushman FD, Choe S, Biochemistry. 1999 Jul 13;38(28):8892-8. PMID:10413462
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