InterPro: IPR002464 DNA/RNA helicase, ATP-dependent, DEAH-box type, conserved site

A number of eukaryotic and prokaryotic proteins have been characterised [1, 2, 3] on the basis of their structural similarity. They all seem to be involved in ATP-dependent, nucleic-acid unwinding. There are two subfamilies of such proteins, the D-E-A-D-box and D-E-A-H-box families. Proteins that belong to the subfamily which have His instead of the second Asp are said to be 'D-E-A-H-box' proteins [3, 4, 5].

Proteins currently known to belong to this subfamily include yeast PRP2, PRP16, PRP22 and PRP43, involved in various ATP-requiring steps of the pre-mRNA splicing process; fission yeast prh1, which my be involved in pre-mRNA splicing; Drosophila male-less (mle) protein required in males for dosage compensation of X chromosome linked genes; yeast RAD3, a DNA helicase involved in excision repair of DNA damaged by UV light, bulky adducts or cross-linking agents; fission yeast rad15 (rhp3) and mammalian DNA excision repair protein XPD (ERCC-2); yeast CHL1 (or CTF1), which is important for chromosome transmission and normal cell cycle progression in G(2)/M; yeast TPS1, Caenorhabditis elegans hypothetical proteins C06E1.10 and K03H1.2; Poxviruses' early transcription factor 70kDa subunit which acts with RNA polymerase to initiate transcription from early gene promoters; Vaccinia virus putative helicase I8; and Escherichia coli putative RNA helicase hrpA. All these proteins share a number of conserved sequence motifs. Some of them are specific to this family while others are shared by other ATP-binding proteins or by proteins belonging to the helicases `superfamily' [6].