Investigation of the protease domain of the lacticin 481 transporter LctT

ORGN 662

Leigh Anne Furgerson, furgerso@uiuc.edu, Department of Chemistry, University of Illinois Urbana-Champaign, 600 S. Matthews, Urbana, IL 61801, Champak Chatterjee, chatterj@uiuc.edu, Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S Mathews Ave., Urbana, IL 61801, and Wilfred A. van der Donk, Department of Chemistry, University of Illinois, 600 S. Mathews Ave, Urbana, IL 61801.
Lacticin 481 is a lanthionine-containing bacteriocin (lantibiotic) produced by the Gram-positive bacteria Lactococcus lactis subsp. lactis. The final steps of lacticin 481 biosynthesis are cleavage of an N-terminal leader sequence from the prepeptide LctA followed by export of the mature lantibiotic. Both cleavage and export are performed by the dedicated ATP-binding cassette (ABC) transporter LctT. LctT belongs to the recently described family of AMS (ABC transporter maturation and secretion) proteins whose prepeptide substrates share a conserved double-glycine type cleavage site. While the in vitro activity of a non-lantibiotic bacteriocin protease, LagD, has been previously described by Håvarstein and co-workers, the activity of a lantibiotic protease has not yet been characterized. We report the purification and in vitro activity of the protease domain of LctT, which exhibited a permissive substrate scope.