RecJ from Bacillus halodurans possesses endonuclease activity at moderate temperature

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• RecJ homologs are conserved proteins in prokaryotes and eukaryotes, primarily known for their exonuclease activity on single-stranded DNA.
• This activity is crucial for DNA damage repair and recombination pathways.

Discussion:

• This research details the discovery of a novel RecJ protein from Bacillus halodurans (BhRecJ) with distinct endonuclease activity on double-stranded DNA.
• Unlike typical RecJ proteins, BhRecJ cleaves supercoiled plasmids into open circular and linear forms, suggesting a different functional role.
• The study highlights a unique C-terminal domain in BhRecJ, potentially responsible for its endonuclease function, and identifies key residues involved in this activity.

Key Insights:

• Bacillus halodurans RecJ (BhRecJ) exhibits novel endonuclease activity on double-stranded DNA, diverging from the established exonuclease function of RecJ family proteins.
• BhRecJ possesses a unique C-terminal domain and specific essential residues that contribute to its distinct enzymatic function.
• The findings suggest that RecJ proteins may participate in a broader range of biological processes than previously understood.

Outlook:

• Further investigation into the novel C-terminal domain of BhRecJ is warranted to fully elucidate its structural and functional significance.
• Exploring the biological pathways and substrates associated with BhRecJ's endonuclease activity could reveal new roles for RecJ proteins.
• Comparative studies with other RecJ homologs may uncover additional functional diversity within this protein family.