Plant Cell and Viral Helicases: Essential Enzymes for Nucleic Acid Transactions

Abstract

ABSTRACT Helicases are ubiquitous enzymes that catalyze the unwinding of energetically stable duplex DNA (DNA helicases) or duplex RNA secondary structures (RNA helicases) and thus play essential role in all aspects of nucleic acid metabolism. All helicases share the common property of being able to use the energy derived from NTP hydrolysis (usually ATP) to break the hydrogen bonds that hold both the two strands together. Mechanistically, there are two classes of helicases: those that can translocate 3′- to 5′-, or 5′- to 3′- directions with respect to the strand on which they initially bind. DNA helicases are essential for key biological processes such as the DNA replication, repair, recombination, and transcription. Similarly, RNA helicases represent a large family of proteins that are involved in modulation of RNA structure and thereby influencing RNA synthesis, splicing, replication, translation initiation, editing, rRNA processing, ribosome assembly, nuclear mRNA export, mRNA stabilization, and degr...