Biochemical and Genetic Characterization of Propionicin T1, a New Bacteriocin from Propionibacterium thoenii

Abstract

A collection of propionibacteria was screened for bacteriocin production. A new bacteriocin named propionicin T1 was isolated from two strains of Propionibacterium thoenii. This bacteriocin shows no sequence similarity to other bacteriocins. Propionicin T1 was active against all strains of Propionibacterium acidipropionici, Propionibacterium thoenii, and Propionibacterium jensenii tested and also against Lactobacillus sake NCDO 2714 but showed no activity against Propionibacterium freudenreichii. The bacteriocin was purified, and the N-terminal part of the peptide was determined with amino acid sequencing. The corresponding gene pctA was sequenced, and this revealed that propionicin T1 is produced as a prebacteriocin of 96 amino acids with a typical sec leader, which is processed to give a mature bacteriocin of 65 amino acids. An open reading frame encoding a protein of 424 amino acids was found 68 nucleotides downstream the stop codon of pctA. The N-terminal part of this putative protein shows strong similarity with the ATP-binding cassette of prokaryotic and eukaryotic ABC transporters, and this protein may be involved in self-protection against propionicin T1. Propionicin T1 is the first bacteriocin from propionibacteria that has been isolated and further characterized at the molecular level.

Dairy Propionibacteria: Less Conventional Probiotics to Improve the Human and Animal Health

“…Among them it could be mentioned: Propionicin PLG-1 and GBZ-1 produced by P. thoenii 127 [81]; Jenseniin G isolated from P. thoenii P126 [82]; Propionicins SM1 and SM2 produced by P. jensenii DF1 [83]; Propionicin T1 synthesized by P. thoenii 419 and LMG2792 [84]; Thoenicin 447 isolated from P. thoenii 447 [85]; Acnecin produced by a strain of P. acnes [86] and several other propionicins [87][88][89].…”

Bacteriocins of propionic acid bacteria

“…Propionicin T1 is the only known PAB bacteriocin that is produced in easily detectable amounts during growth [7]. Two strains, P. thoenii 419 and P. thoenii LMG 2792 both produce this bacteriocin.…”

Genetics and molecular biology of propionibacteria

“…[12] protoporphyrinogen oxidase hemY P. freud. [12] Cellular processes propionicin T1 pctA P. thoenii [6] putative immunity protein orf2 P. thoenii [6] propionicin SM1 ppnA P. jensenii [25,26,42] Other functions 60 kg . [41] proline iminopeptidase pip P. freud.…”

“…pRG01 [17] repA P. jensenii pLME106 [26,42] repA P. freud. p545 [16] replication protein repB as for repA as for repA [6]. The latter is part of an operon together with its putative immunity protein encoding gene (orf2) [6].…”