1gx6: Difference between revisions

Revision as of 13:54, 21 February 2008

HEPATITIS C VIRUS RNA POLYMERASE IN COMPLEX WITH UTP AND MANGANESE

OverviewOverview

We report here the results of a systematic high-resolution X-ray crystallographic analysis of complexes of the hepatitis C virus (HCV) RNA polymerase with ribonucleoside triphosphates (rNTPs) and divalent metal ions. An unexpected observation revealed by this study is the existence of a specific rGTP binding site in a shallow pocket at the molecular surface of the enzyme, 30 A away from the catalytic site. This previously unidentified rGTP pocket, which lies at the interface between fingers and thumb, may be an allosteric regulatory site and could play a role in allowing alternative interactions between the two domains during a possible conformational change of the enzyme required for efficient initiation. The electron density map at 1.7-A resolution clearly shows the mode of binding of the guanosine moiety to the enzyme. In the catalytic site, density corresponding to the triphosphates of nucleotides bound to the catalytic metals was apparent in each complex with nucleotides. Moreover, a network of triphosphate densities was detected; these densities superpose to the corresponding moieties of the nucleotides observed in the initiation complex reported for the polymerase of bacteriophage phi6, strengthening the proposal that the two enzymes initiate replication de novo by similar mechanisms. No equivalent of the protein stacking platform observed for the priming nucleotide in the phi6 enzyme is present in HCV polymerase, however, again suggesting that a change in conformation of the thumb domain takes place upon template binding to allow for efficient de novo initiation of RNA synthesis.

About this StructureAbout this Structure

1GX6 is a Single protein structure of sequence from Hepatitis c virus genotype 1b (isolate bk) with and as ligands. Active as RNA-directed RNA polymerase, with EC number 2.7.7.48 Known structural/functional Site: . Full crystallographic information is available from OCA.

ReferenceReference

Structural analysis of the hepatitis C virus RNA polymerase in complex with ribonucleotides., Bressanelli S, Tomei L, Rey FA, De Francesco R, J Virol. 2002 Apr;76(7):3482-92. PMID:11884572

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 ==Overview==
-We report here the results of a systematic high-resolution X-ray, crystallographic analysis of complexes of the hepatitis C virus (HCV) RNA, polymerase with ribonucleoside triphosphates (rNTPs) and divalent metal, ions. An unexpected observation revealed by this study is the existence of, a specific rGTP binding site in a shallow pocket at the molecular surface, of the enzyme, 30 A away from the catalytic site. This previously, unidentified rGTP pocket, which lies at the interface between fingers and, thumb, may be an allosteric regulatory site and could play a role in, allowing alternative interactions between the two domains during a, possible conformational change of the enzyme required for efficient, initiation. The electron density map at 1.7-A resolution clearly shows the, mode of binding of the guanosine moiety to the enzyme. In the catalytic, site, density corresponding to the triphosphates of nucleotides bound to, the catalytic metals was apparent in each complex with nucleotides., Moreover, a network of triphosphate densities was detected; these, densities superpose to the corresponding moieties of the nucleotides, observed in the initiation complex reported for the polymerase of, bacteriophage phi6, strengthening the proposal that the two enzymes, initiate replication de novo by similar mechanisms. No equivalent of the, protein stacking platform observed for the priming nucleotide in the phi6, enzyme is present in HCV polymerase, however, again suggesting that a, change in conformation of the thumb domain takes place upon template, binding to allow for efficient de novo initiation of RNA synthesis.
+We report here the results of a systematic high-resolution X-ray crystallographic analysis of complexes of the hepatitis C virus (HCV) RNA polymerase with ribonucleoside triphosphates (rNTPs) and divalent metal ions. An unexpected observation revealed by this study is the existence of a specific rGTP binding site in a shallow pocket at the molecular surface of the enzyme, 30 A away from the catalytic site. This previously unidentified rGTP pocket, which lies at the interface between fingers and thumb, may be an allosteric regulatory site and could play a role in allowing alternative interactions between the two domains during a possible conformational change of the enzyme required for efficient initiation. The electron density map at 1.7-A resolution clearly shows the mode of binding of the guanosine moiety to the enzyme. In the catalytic site, density corresponding to the triphosphates of nucleotides bound to the catalytic metals was apparent in each complex with nucleotides. Moreover, a network of triphosphate densities was detected; these densities superpose to the corresponding moieties of the nucleotides observed in the initiation complex reported for the polymerase of bacteriophage phi6, strengthening the proposal that the two enzymes initiate replication de novo by similar mechanisms. No equivalent of the protein stacking platform observed for the priming nucleotide in the phi6 enzyme is present in HCV polymerase, however, again suggesting that a change in conformation of the thumb domain takes place upon template binding to allow for efficient de novo initiation of RNA synthesis.
 ==About this Structure==
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 [[Category: Single protein]]
 [[Category: Bressanelli, S.]]
-[[Category: Rey, F.A.]]
+[[Category: Rey, F A.]]
 [[Category: MN]]
 [[Category: UTP]]
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 [[Category: virus replication]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:43:46 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:54:57 2008''