Archaeal Enzyme Complex for Multifunctional Nucleic Acid Degradation

Activates Disparate Degradation Processes Using Tunable Concentration of RecJ Enzymes

This nuclease complex integrates enzymes from an extremophile single-celled organism into a nuclease with versatile nucleic acid degradation abilities. Nucleases, a class of enzymes within cells, degrade nucleic acids by breaking long strands into shorter ones. Ribonuclease (RNase) is a subclass of nucleases targeting ribonucleic acid (RNA). RNA hydrolysis is central to cell biology. The degradation of mRNA is an essential mechanism for regulating gene expression, controlled in response to environmental, development, and metabolic queues. Cells must maintain RNA quality to prevent the damaging effects of aberrant non-coding RNA accumulates or when translating defective mRNA. Since RNA participates in various cell processes, RNase is likewise essential in the background of these processes, preventing the build-up of RNA after its use and removing it when it is faulty. Different types of RNase degrade RNA from the end or center of the strand. These are known as exoribonuclease or endoribonuclease, respectively. Furthermore, RNase typically cannot degrade single-strand deoxyribonucleic acid (ssDNA) despite the structural similarity of ssDNA to RNA. A multifaceted nuclease combining endo- and exoribonuclease behavior with the ability to degrade ssDNA is a sought-after tool.

Researchers at the University of Florida have developed a nuclease complex by aggregating RecJ enzymes from the single-celled Archaeal organism, Haloferax valocanii. The end product can break down RNA from the end or center of the strand and degrade ssDNA. This broad degrading power is beneficial in cleaning processes, such as reverse transcription that leaves unwanted RNA and ssDNA.

Application

Endo- and exonuclease functionality for degradation of RNA and ssDNA

Advantages

• Applies biochemical structures from the domain Archaea to human cells, taking advantage of their similar enzymatic processes regarding nucleic acids
• Integrates both exonuclease and endonuclease characters into one complex, controlling the direction of degradation via enzyme concentration
• Degrades both RNA and single-strand DNA, facilitating the maintenance of hybrid systems, such as RNA-DNA helices

Technology

Organisms in the domain Archaea typically live in extreme environments and, despite being prokaryotic and single-celled like most bacteria, their nucleic acids and associated enzymes function similarly to those of eukaryotes. As a result, scientists study essential biological processes such as DNA transcription and RNA degradation in archaea such as the salt-loving Haloferax volcanii. This organism contains three noteworthy nucleases: RecJ3 and RecJ4, capable of degrading ssDNA from the end, and aRNase J, an RNA degrading machine. The enzyme complex combines an aggregate of RecJ3 and RecJ4 with a variable concentration of aRNase J. This achieves on-demand tuning between endoribonuclease behavior when aRNase J is the larger portion of the ratio and exoribonuclease behavior when aRNase J is the smaller portion.