Bacteriocin AS-48 is a cyclic peptide antibiotic produced by the eubacteria Enterococcus faecalis (Streptococcus faecalis) that shows a broad antimicrobial spectrum against both Gram-positive and Gram-negative bacteria. Bacteriocin AS-48 is encoded by the pheromone-responsive plasmid pMB2, and acts on the plasma membrane in which it opens pores leading to ion leakage and cell death.[1] The globular structure of bacteriocin AS-48 is composed of five alpha helices enclosing a hydrophobic core. The mammalian NK-lysin effector protein of T and natural killer cells has a similar structure, though it lacks sequence homology with bacteriocins AS-48.
| Bacteriocin_IId | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 x-ray structure of bacteriocin as-48 at ph 4.5. sulphate bound form | |||||||||
| Identifiers | |||||||||
| Symbol | Bacteriocin_IId | ||||||||
| Pfam | PF09221 | ||||||||
| InterPro | IPR009086 | ||||||||
| SCOP2 | 1o82 / SCOPe / SUPFAM | ||||||||
| TCDB | 1.C.28 | ||||||||
| |||||||||
Bacteriocin uses components of the mannose phosphotransferase system (man-PTS)[2] of susceptible cells as target/receptor. The immunity protein LciA forms a strong complex with the receptor proteins and the bacteriocin, thereby preventing cells from being killed. The complex between LciA and the man-PTS components (IIAB, IIC, and IID) appears to involve an on–off type mechanism that allows complex formation only in the presence of bacteriocin; otherwise no complexes were observed between LciA and the receptor proteins.[3]
References
edit- ^ González C, Langdon GM, Bruix M, Gálvez A, Valdivia E, Maqueda M, Rico M (October 2000). "Bacteriocin AS-48, a microbial cyclic polypeptide structurally and functionally related to mammalian NK-lysin". Proc. Natl. Acad. Sci. U.S.A. 97 (21): 11221–6. Bibcode:2000PNAS...9711221G. doi:10.1073/pnas.210301097. PMC 17181. PMID 11005847.
- ^ Liu, Xueli; Zeng, Jianwei; Huang, Kai; Wang, Jiawei (2019-06-17). "Structure of the mannose transporter of the bacterial phosphotransferase system". Cell Research. 29 (8): 680–682. doi:10.1038/s41422-019-0194-z. ISSN 1748-7838. PMC 6796895. PMID 31209249.
- ^ Kjos M, Nes IF, Diep DB (2011). "Mechanisms of resistance to bacteriocins targeting the mannose phosphotransferase system". Appl Environ Microbiol. 77 (10): 3335–42. Bibcode:2011ApEnM..77.3335K. doi:10.1128/AEM.02602-10. PMC 3126464. PMID 21421780.