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RNA helicase activity of Semliki Forest virus replicase protein NSP2
Author(s) -
Gomez de Cedrón Marta,
Ehsani Neda,
Mikkola Marja L.,
Garcı́a Juan Antonio,
Kääriäinen Leevi
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00321-x
Subject(s) - semliki forest virus , rna dependent rna polymerase , rna helicase a , virology , rna , degradosome , helicase , chemistry , biology , biochemistry , gene
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 α‐ 32 P‐labelled partially double‐stranded RNA required nsP2, Mg 2+ and NTPs. NsP2 with a mutation, K192N, in the NTP‐binding sequence GVPGSGK 192 SA could not unwind dsRNA and had no NTPase activity. This is the first demonstration of RNA helicase activity within the large alphavirus superfamily.