Published Online: 15 FEB 2012
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Bianco, P. R. 2012. DNA Helicases. eLS. .
- Published Online: 15 FEB 2012
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) helicases are organised into six SuperFamilies (SF) of enzymes using sequence alignments, biochemical data and available crystal structures. DNA helicases, members of which are found in each of the SF, are an essential group of motor proteins that unwind DNA duplexes into their component single strands in a process that is coupled to the hydrolysis of nucleoside 5′-triphosphates (NTPs). These enzymes share common biochemical properties that include the binding of single- and double-stranded DNA, NTP binding and hydrolysis, and NTP hydrolysis-coupled, polar unwinding of duplex DNA. DNA helicases participate in every aspect of DNA metabolism due to the requirement for transient separation of small regions of the duplex genome into its component strands so that replication, recombination and repair can occur.
DNA helicases unwind duplex DNA in catalytic fashion.
DNA helicases translocate unidirectionally in polar fashion.
Helicases hydrolyse nucleoside triphosphates.
DNA helicases are critical to all aspects of DNA metabolism.
There are two broad classes of DNA helicases: hexameric and nonhexameric.
- protein–DNA complexes;
- hexameric rings;
- DNA unwinding