Term: helicase
Literally meaning: “protein of unwinding
helix”
Origin: Anc Greek
ελίσσω/elisso(=twist, turn)
> ?åλιξ/helix(=helix, something spiral)
+-άση/-asy(=-ase) suffix added to the name of
the substrate that the enzyme hydrolyzes
eg proteinase for protein or lipase for lipids
>διά-/dia-(=prefix denoting “through”, “apart” )
> δυο/dio(two) + στάσις/stasis(=halt)
> ίστημι/histimi(=stand).
Coined/History
The
discovery of first helicase was in 1976 in pocaryotic organism (Escherichia
coli ) and two years later in an the eucaryotic lily . The enzymes were classified then as “unwinding
proteins” and first time as helicases in 1982 by Venkatesan et al. Since then a
large number of these enzymes have been isolated from both procaryotic and eukaryotic systems,
and the number is still growing.
Sources
1. Abdel-Monem, M., Durwald, H. & Hoffmann-Berling, H. (1976) Enzymic unwinding of DNA. II.
Chain separation by an ATP-dependent DNA unwinding enzyme. Eur. J. Biochem.
65,441–449.
2. Hotta,
Y. & Stern, H. (1978) DNA unwinding protein from meiotic cells of Lilium.
Biochemistry 17, 1872–1880.
3.
Venkatesan, M., Silver, I.L. & Nossal, N.G. (1982) Bacteriophage T4 gene 41
protein, required for the synthesis of RNA primers, is also a DNA helicase. J.
Biol. Chem. 257, 12426–12434.
Definition
Helicases
are a group of enzymes that, using ATP, move along a nucleic acid
phopsphodiester backbone in order to unwind and separate two annealed nucleic
acids strands. Helicases are essential in nucleic acid metabolism , including
replication, repair, recombination, and transcription. at replication fork.
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