A unique lantibiotic, thermophilin 1277, containing a disulfide bridge and two thioether bridges.
J Appl Microbiol
; 106(3): 853-62, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-19191960
ABSTRACT
AIMS:
To identify the chemical structure of a bacteriocin, thermophilin 1277, produced by Streptococcus thermophilus SBT1277. METHODS ANDRESULTS:
Thermophilin 1277 was purified and partial N-terminal sequence analysis revealed 6 unidentified amino acids amongst 31 amino acids residues. A 2.7-kbp region containing the thermophilin 1277 structural gene (tepA) encoding 58 amino acids was cloned and sequenced. Mature thermophilin 1277 (33 amino acids) was preceded by a 25-amino acid putative leader peptide containing a double glycine cleavage motif. Peptide sequence analysis following chemical modification of thermophilin 1277 revealed that the Cys21 and Cys29 residues form a disulfide bridge and that Thr8 or Thr10 forms two 3-methyllanthionines with Cys13 or Cys32 via thioether bridges. Antimicrobial activity was disrupted by ethanethiol or reductive agent treatments, indicating that the internal amino acid modifications are crucial for the activity.CONCLUSIONS:
Thermophilin 1277 from Strep. thermophilus SBT1277 belongs to the class of AII-type lantibiotics that has a disulfide and two thioether bridges. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report of a lantibiotic produced by a GRAS species of Strep. thermophilus; thermophilin 1277 has a unique structure containing both a disulfide bridge and two thioether bridges that are crucial for its activity.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bacteriocinas
/
Streptococcus thermophilus
/
Antibacterianos
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article