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1: FEBS Lett. 1999 Apr 1;448(1):19-22.Click here to read Links

RNA helicase activity of Semliki Forest virus replicase protein NSP2.

Gomez de Cedrón M, Ehsani N, Mikkola ML, García JA, Kääriäinen L.

Centro de Biologia Molecular (CSIC-UAM), Universidad Autónoma, Canto Blanco, Madrid, Spain.

Semliki Forest virus replicase protein nsP2 shares sequence homology with several putative NTPases and RNA helicases. NsP2 has RNA-dependent NTPase activity. Here we expressed polyhistidine-tagged nsP2 in Escherichia coli, purified it by metal-affinity chromatography, and used it in RNA helicase assays. RNA helicase CI of plum pox potyvirus was used as a positive control. Unwinding of alpha-32P-labelled partially double-stranded RNA required nsP2, Mg2+ and NTPs. NsP2 with a mutation, K192N, in the NTP-binding sequence GVPGSGK192SA could not unwind dsRNA and had no NTPase activity. This is the first demonstration of RNA helicase activity within the large alphavirus superfamily.

PMID: 10217401 [PubMed - indexed for MEDLINE]