helicase

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.