F
IPR016406

Cystovirus, RNA-directed RNA polymerase

InterPro entry
Short nameCystovir_RNA-dir_pol
Overlapping
homologous
superfamilies
 

Description

RNA-directed RNA polymerase (RdRp) (
2.7.7.48
) is an essential protein encoded in the genomes of all RNA containing viruses with no DNA stage
[3, 4]
. It catalyses synthesis of the RNA strand complementary to a given RNA template, but the precise molecular mechanism remains unclear. The postulated RNA replication process is a two-step mechanism. First, the initiation step of RNA synthesis begins at or near the 3' end of the RNA template by means of a primer-independent (de novo) mechanism. The de novo initiation consists in the addition of a nucleotide tri-phosphate (NTP) to the 3'-OH of the first initiating NTP. During the following so-called elongation phase, this nucleotidyl transfer reaction is repeated with subsequent NTPs to generate the complementary RNA product
[5]
.

This entry represents RNA-directed RNA polymerase (also known as protein P2) from various Cystoviruses, such as Bacteriophage phi-6 and Bacteriophage phi-13
[1]
. The RdRp protein of Cystoviruses is capable of primer-independent initiation, as are many RNA polymerases. The structure of this polymerase revealed an initiation platform, composed of a loop in the C-terminal domain that was essential for de novo initiation, a similar element having been identified in Hepatitis C virus RNA-dependent RNA polymerase
[2]
.

References

1.RNA-dependent RNA polymerases of dsRNA bacteriophages. Makeyev EV, Grimes JM. Virus Res. 101, 45-55, (2004). View articlePMID: 15010216

2.Back-priming mode of phi6 RNA-dependent RNA polymerase. Laurila MR, Salgado PS, Stuart DI, Grimes JM, Bamford DH. J. Gen. Virol. 86, 521-6, (2005). View articlePMID: 15659773

3.Tentative identification of RNA-dependent RNA polymerases of dsRNA viruses and their relationship to positive strand RNA viral polymerases. Koonin EV, Gorbalenya AE, Chumakov KM. FEBS Lett. 252, 42-6, (1989). View articlePMID: 2759231

4.A reevaluation of the higher taxonomy of viruses based on RNA polymerases. Zanotto PM, Gibbs MJ, Gould EA, Holmes EC. J. Virol. 70, 6083-96, (1996). View articlePMID: 8709232

5.De novo initiation of viral RNA-dependent RNA synthesis. Kao CC, Singh P, Ecker DJ. Virology 287, 251-60, (2001). View articlePMID: 11531403

Further reading

6. Structure of the RNA-dependent RNA polymerase of poliovirus. Hansen JL, Long AM, Schultz SC. Structure 5, 1109-22, (1997). View articlePMID: 9309225

7. Poliovirus RNA-dependent RNA polymerase (3Dpol): structural, biochemical, and biological analysis of conserved structural motifs A and B. Gohara DW, Crotty S, Arnold JJ, Yoder JD, Andino R, Cameron CE. J. Biol. Chem. 275, 25523-32, (2000). View articlePMID: 10827187

8. Analysis of RNA-dependent RNA polymerase structure and function as guided by known polymerase structures and computer predictions of secondary structure. O'Reilly EK, Kao CC. Virology 252, 287-303, (1998). View articlePMID: 9878607

GO terms

molecular function

  • None

cellular component

  • None

Cross References

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