Department of Dairy Science and Technology, Instituto del Frío (CSIC), Ciudad Universitaria, Madrid, Spain Carmen Martínez-Cuesta Teresa Requena Elisabet Herranz Carmen Peláez Department of Biochemistry, University of Oslo, Norway Havard Hauge Jon Nissen-Meyer Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen Jan Kok The two peptide lantibiotic lacticin 3147 is effective in bacteriocin induced lysis Girbe Buist

Bacteriocin characteristics n produced by L. lactis IFPL105, isolated from Spanish raw goats’ milk n heat stable n broad spectrum of inhibitory activity n hydrolyzed by chymotrypsin, proteinase K and pancreatin n resistant to trypsin and pepsin n genes for immunity and production located on 46 kb plasmid pBAC105

Purification

Reverse-phase chromatography n  peptide is 3322 Da n  peptide is 2848 Da n complementary action needed for activity 

Amino acid and nucleotide sequence n N-termini blocked n  peptide cleft by chymotrypsin n Edman: Ile-(Ser)-Thr-Asn-Thr-(Glu)-Pro n homologous to a peptide of lacticin 3147 n ltnA1 encodes a peptide of 59 aa n ltnA2 encodes a peptide of 62 aa n ‘double-Gly’ type leader peptides

Amino acid composition n LtnA1 and LtnA2 are post-translational modified n Ser > D-Ala conversion shown and lanthionine present

ltn operon ~ 13 Kb n gene organization in pBAC105 and pMRC01 are identical

Lacticin 3147 n produced by L. lactis DPC3147 isolated from Irish kefir grain n PMF promotes the interaction with membrane n pores are selective for K + ions and inorganic phosphate n dissipation of the membrane potential > hydrolysis of ATP > collapse of the pH gradient > cell death n induces cell lysis n lytic response is strain dependent

Growth (OD 600 ) Time (h) Lb. casei IFPL731 L. lactis IFPL Growth (OD 600 ) Time (h) Growth (OD 600 ) Time (h) Lb. rhamnosus JCL hours3 hours% lysis 1.0   (1.5) 6.0   (0.8) 0 hours3 hours% lysis 3.3   (2.3) 5.3   (1.2) 0 hours3 hours% lysis 6.8   (1.3) 5.4   (3.7) n loss of viability not concurrent with cell lysis n addition of Co 2+ or SDS reduces lysis Lacticin 3147 induced lysis

AcmA: responsible for autolysis Time in hours OD[600nm] MG1363 MG1363acmA

Time (h) OD Units of PepX / ml MG1363 Involvement of AcmA in lacticin induced lysis

n reduction of viability identical n AcmA responsible for lacticin 3147 induced lysis Involvement of AcmA in lacticin induced lysis

Cell wall degradation n Lacticin 3147 does not activate AcmA n similar results obtained when using Nisin or a mixture of lactococcins A, B, and M

Depletion of cellular energy causes an imbalance in the control of the action of the autolysin, resulting in cell wall degradation and, thus, cell lysis. Conclusion