NS5B: Difference between revisions

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'''NS5B''' is the '''RNA dependent RNA polymerase''' of Hepatitis C virus. NS5B, like other RNA dependent RNA polymerases, is error prone. This viral RNA replicase is of approximately a million times lower fidelity than a replicative prokayrotic or eukaryotic DNA polymerase. This is due in part to the fact that NS5B contains no exonuclease or proofreading domain. IN NS5B two divalent cations coordinated by carboxyl groups (as seen in DNA polymerases) catalyze the polymerization of monomers of RNA triphosphates to extend a primer strand, that may have initiated ''de novo''. In the case of NS5B the residues that coordinate divalent cations (Mg2+ or Mn2+ ''in vitro'') are the three <scene name='NS5B/Native_ns5b/7'>active site aspartates (220, 318 and 319)</scene> seen here (PDB entry [[2hai]]).

Though Hepatitis C virus is of the Flaviviridae family the structure of NS5B is similar to the polymerase of bacteriophage Φ 6. The similarity to the bacteriophage polymerase is due to NS5B containing a fully encircled active site. Like many template-dependent nucleotide polymerases, NS5B can be visualized similar to a right hand. NS5B contains several <scene name='NS5B/Native_ns5b/8'>domains</scene>, fingers in blue, palm in magenta, thumb in green and a c-terminal domain in yellow. The palm domain contains the active site aspartates and there are several contacts between the fingers and thumbs domain that give the active site an encircled structure. There is a

Though Hepatitis C virus is of the Flaviviridae family the structure of NS5B is similar to the polymerase of bacteriophage Φ 6. The similarity to the bacteriophage polymerase is due to NS5B containing a fully encircled active site. Like many template-dependent nucleotide polymerases, NS5B can be visualized similar to a right hand. NS5B contains several <scene name='NS5B/Native_ns5b/8'>domains</scene>, fingers in blue, palm in magenta, thumb in green and a c-terminal domain in yellow. Specific to Hepatitis C virus family, the NS5B protein has a 21-24 residue hydrophobic membrane anchor at its C-termini that allows involvement with the replication complex that is located in membrane bound vesicles derived from the endoplasmic reticulum. The palm domain contains the active site aspartates and there are several contacts between the fingers and thumbs domain that give the active site an encircled structure. There is a <scene name='NS5B/Native_ns5b/9'>beta-hairpin in thumb domain</scene> that is proposed to move upon formation of exiting double-stranded RNA.

<scene name='NS5B/Native_ns5b/9'>beta-hairpin in thumb domain</scene> that is proposed to move upon formation of exiting double stranded RNA.

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 '''NS5B''' is the '''RNA dependent RNA polymerase''' of Hepatitis C virus. NS5B, like other RNA dependent RNA polymerases, is error prone. This viral RNA replicase is of approximately a million times lower fidelity than a replicative prokayrotic or eukaryotic DNA polymerase. This is due in part to the fact that NS5B contains no exonuclease or proofreading domain. IN NS5B two divalent cations coordinated by carboxyl groups (as seen in DNA polymerases) catalyze the polymerization of monomers of RNA triphosphates to extend a primer strand, that may have initiated ''de novo''. In the case of NS5B the residues that coordinate divalent cations (Mg2+ or Mn2+ ''in vitro'') are the three <scene name='NS5B/Native_ns5b/7'>active site aspartates (220, 318 and 319)</scene> seen here (PDB entry [[2hai]]).
-Though Hepatitis C virus is of the Flaviviridae family the structure of NS5B is similar to the polymerase of bacteriophage Φ 6. The similarity to the bacteriophage polymerase is due to NS5B containing a fully encircled active site. Like many template-dependent nucleotide polymerases, NS5B can be visualized similar to a right hand. NS5B contains several <scene name='NS5B/Native_ns5b/8'>domains</scene>, fingers in blue, palm in magenta, thumb in green and a c-terminal domain in yellow. The palm domain contains the active site aspartates and there are several contacts between the fingers and thumbs domain that give the active site an encircled structure. There is a
+Though Hepatitis C virus is of the Flaviviridae family the structure of NS5B is similar to the polymerase of bacteriophage Φ 6. The similarity to the bacteriophage polymerase is due to NS5B containing a fully encircled active site. Like many template-dependent nucleotide polymerases, NS5B can be visualized similar to a right hand. NS5B contains several <scene name='NS5B/Native_ns5b/8'>domains</scene>, fingers in blue, palm in magenta, thumb in green and a c-terminal domain in yellow. Specific to Hepatitis C virus family, the NS5B protein has a 21-24 residue hydrophobic membrane anchor at its C-termini that allows involvement with the replication complex that is located in membrane bound vesicles derived from the endoplasmic reticulum. The palm domain contains the active site aspartates and there are several contacts between the fingers and thumbs domain that give the active site an encircled structure. There is a <scene name='NS5B/Native_ns5b/9'>beta-hairpin in thumb domain</scene> that is proposed to move upon formation of exiting double-stranded RNA.
-<scene name='NS5B/Native_ns5b/9'>beta-hairpin in thumb domain</scene> that is proposed to move upon formation of exiting double stranded RNA.