A number of eukaryotic and prokaryotic proteins have been characterized [1,2,3] on the basis of their structural similarity. They all seem to be involved
in ATP-dependent, nucleic-acid unwinding. Proteins currently known to belong
to this family are:
Initiation factor eIF-4A. Found in eukaryotes, this protein is a subunit of
a high molecular weight complex involved in 5'cap recognition and the
binding of mRNA to ribosomes. It is an ATP-dependent RNA-helicase.
PRP5 and PRP28. These yeast proteins are involved in various ATP-requiring
steps of the pre-mRNA splicing process.
Pl10, a mouse protein expressed specifically during spermatogenesis.
An3, a Xenopus putative RNA helicase, closely related to Pl10.
SPP81/DED1 and DBP1, two yeast proteins probably involved in pre-mRNA
splicing and related to Pl10.
Caenorhabditis elegans helicase glh-1.
MSS116, a yeast protein required for mitochondrial splicing.
SPB4, a yeast protein involved in the maturation of 25S ribosomal RNA.
p68, a human nuclear antigen. p68 has ATPase and DNA-helicase activities in
vitro. It is involved in cell growth and division.
Rm62 (p62), a Drosophila putative RNA helicase related to p68.
DBP2, a yeast protein related to p68.
DHH1, a yeast protein.
DRS1, a yeast protein involved in ribosome assembly.
MAK5, a yeast protein involved in maintenance of dsRNA killer plasmid.
ROK1, a yeast protein.
ste13, a fission yeast protein.
Vasa, a Drosophila protein important for oocyte formation and specification
of of embryonic posterior structures.
Me31B, a Drosophila maternally expressed protein of unknown function.
dbpA, an Escherichia coli putative RNA helicase.
deaD, an Escherichia coli putative RNA helicase which can suppress a
mutation in the rpsB gene for ribosomal protein S2.
rhlB, an Escherichia coli putative RNA helicase.
rhlE, an Escherichia coli putative RNA helicase.
srmB, an Escherichia coli protein that shows RNA-dependent ATPase activity.
It probably interacts with 23S ribosomal RNA.
Caenorhabditis elegans hypothetical proteins T26G10.1, ZK512.2 and ZK686.2.
Yeast hypothetical protein YHR065c.
Yeast hypothetical protein YHR169w.
Fission yeast hypothetical protein SpAC31A2.07c.
Bacillus subtilis hypothetical protein yxiN.
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' . One
of these motifs, called the 'D-E-A-D-box', represents a special version of the
B motif of ATP-binding proteins.
Some other proteins belong to a subfamily which have His instead of the second
Asp and are thus said to be 'D-E-A-H-box' proteins [3,5,6]. Proteins
currently known to belong to this subfamily are:
PRP2, PRP16, PRP22 and PRP43. These yeast proteins are all involved in
various ATP-requiring steps of the pre-mRNA splicing process.
Fission yeast prh1, which my be involved in pre-mRNA splicing.
Male-less (mle), a Drosophila protein required in males, for dosage
compensation of X chromosome linked genes.
RAD3 from yeast. RAD3 is 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)
are the homologs of RAD3.
Yeast CHL1 (or CTF1), which is important for chromosome transmission and
normal cell cycle progression in G(2)/M.
Yeast hypothetical protein YKL078w.
Caenorhabditis elegans hypothetical proteins C06E1.10 and K03H1.2.
Poxviruses' early transcription factor 70 Kd subunit which acts with RNA
polymerase to initiate transcription from early gene promoters.
I8, a putative vaccinia virus helicase.
hrpA, an Escherichia coli putative RNA helicase.
We have developed signature patterns for both subfamilies.
Proteins belonging to this family also contain a copy of the ATP/GTP-
binding motif 'A' (P-loop) (see the relevant entry <PDOC00017>).
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