The SfaNI restriction-modification system from Enterococcus faecalis NEB215 is located on a putative mobile genetic...

Area of Science:

• Molecular Biology
• Microbiology
• Genetics

Background:

• Restriction-modification (R-M) systems are crucial for bacterial defense and genome regulation.
• Enterococcus faecalis harbors diverse genetic elements, including mobile ones.

Purpose of the Study:

• To characterize the type IIS R-M system SfaNI from Enterococcus faecalis NEB215.
• To elucidate the genetic organization and protein domains of the SfaNI system.

Main Methods:

• Cloning of the sfaNIM gene using the methylase selection method.
• Purification and biochemical characterization of the SfaNI enzyme.
• Analysis of flanking genes, including transposase and cassette chromosome recombinase (ccr) genes.

Main Results:

• The SfaNI methyltransferase (695 amino acids) possesses distinct DNA-strand recognition domains and an N-terminal HTH DNA-binding domain.
• The SfaNI restriction enzyme (648 amino acids) was purified and biochemically characterized.
• The SfaNI R-M system is flanked by a transposase gene and a ccr gene complex (ccrA and ccrB), suggesting its presence on a mobile element.

Conclusions:

• The SfaNI R-M system exhibits a unique genetic organization.
• The association with transposase and recombinase genes indicates that SfaNI is likely located on a mobile genetic element.
• This finding contributes to understanding R-M system diversity and mobility in Enterococcus species.