BceS1, a new addition to the type III restriction and modification family

Authors

  • Ida K. Hegna,

    Corresponding author
    1. Institute of Pharmacy, Department of microbiology, P.O. Box 1068, University of Oslo, N-0316 Oslo, Norway
    Search for more papers by this author
  • Hege Bratland,

    1. Institute of Pharmacy, Department of microbiology, P.O. Box 1068, University of Oslo, N-0316 Oslo, Norway
    Search for more papers by this author
    • 1Schering-Plough AS, N-1343 Bærum, Norway.

  • Anne-Brit Kolst?

    1. Institute of Pharmacy, Department of microbiology, P.O. Box 1068, University of Oslo, N-0316 Oslo, Norway
    2. Biotechnology Centre of Oslo, P.O. Box 1125, University of Oslo, N-0316 Oslo, Norway
    Search for more papers by this author

*Corresponding author. Tel.: +47 (22) 84 49 34; Fax: +47 (22) 84 49 44, E-mail: i.k.hegna@farmasi.uio.no

Abstract

The nucleotide sequence of an 11-kb chromosomal BglII fragment from Bacillus cereus American Type Culture Collection (ATCC) 10987 strain revealed two closely adjacent open reading frames organized in an operon, of which the deduced amino acids showed identity to the type III restriction and modification (R/M) subunits described in Gram-negative bacteria. An enhanced transcription level was revealed when the culture was grown in the presence of foreign DNA. A cell-free extract from this culture restricted pUC19, whereas from a plain medium the restriction was very weak. The in vitro methylation protected pUC 19 from restriction. The R/M system was designated BceS1 as this endonuclease required ATP and Mg2+ as cofactors like other type III endonucleases. BceS1 is the first chromosomal type III R/M system characterized in a Gram-positive bacterium.

Ancillary