Human DNA helicase VIII: a DNA and RNA helicase corresponding to the G3BP protein, an element of the ras transduction pathway

M Costa; A Ochem; A Staub; A Falaschi

doi:10.1093/nar/27.3.817

Human DNA helicase VIII: a DNA and RNA helicase corresponding to the G3BP protein, an element of the ras transduction pathway

Nucleic Acids Res. 1999 Feb 1;27(3):817-21. doi: 10.1093/nar/27.3.817.

Authors

M Costa¹, A Ochem, A Staub, A Falaschi

Affiliation

¹ International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste, Italy. 163-67404,Illkirch cedex-C. U. de Strasbourg,

Abstract

Human DNA helicase VIII (HDH VIII) was isolated in the course of a systematic study of the DNA unwinding enzymes present in human cells. From a HeLa cell nuclear extract a protein with an Mrof 68 kDa in SDS-PAGE was isolated, characterised and micro-sequenced. The enzyme shows ATP- and Mg2+-dependent activity is not stimulated by RPA, prefers partially unwound 3'-tailed substrates and moves along the bound strand in the 5' to 3' direction. HDH VIII can also unwind partial RNA/DNA and RNA/RNA duplexes. Microsequencing of the polypeptide showed that this enzyme corresponds to G3BP, an element of the Ras pathway which binds specifically to the GTPase-activating protein. HDH VIII/G3BP is analogous to the heterogeneous nuclear ribonucleoproteins and contains a sequence rich in RGG boxes similar to the C-terminal domain of HDH IV/nucleolin, another DNA and RNA helicase.

MeSH terms

Adenosine Triphosphatases / chemistry
Adenosine Triphosphatases / metabolism
Amino Acid Sequence
DNA / metabolism
DNA Helicases / chemistry
DNA Helicases / metabolism
DNA Repair*
DNA-Binding Proteins*
Deoxyribonuclease (Pyrimidine Dimer)
Electrophoresis, Polyacrylamide Gel
Endodeoxyribonucleases / isolation & purification
Endodeoxyribonucleases / metabolism*
Escherichia coli Proteins*
GTP Phosphohydrolases / metabolism*
GTPase-Activating Proteins
HeLa Cells
Humans
Molecular Sequence Data
Molecular Weight
Nucleolin
Phosphoproteins / chemistry
Phosphoproteins / metabolism
Proteins / metabolism*
RNA / metabolism
RNA-Binding Proteins / chemistry
RNA-Binding Proteins / metabolism
ras GTPase-Activating Proteins
ras Proteins / metabolism*

Substances

DNA-Binding Proteins
Escherichia coli Proteins
GTPase-Activating Proteins
Phosphoproteins
Proteins
RNA-Binding Proteins
ras GTPase-Activating Proteins
RNA
DNA
Endodeoxyribonucleases
Deoxyribonuclease (Pyrimidine Dimer)
Adenosine Triphosphatases
GTP Phosphohydrolases
helD protein, E coli
DNA Helicases
ras Proteins