High resolution crystal structure of PedB: a structural basis for the classification of pediocin-like immunity proteins

Abstract

Background: Pediocin-like bacteriocins, ribosomally-synthesized antimicrobial peptides, are generally coexpressed with cognate immunity proteins in order to protect the bacteriocinproducer from its own bacteriocin. As a step for understanding the mode of action of immunity proteins, we determined the crystal structure of PedB, a pediocin-like immunity protein conferring immunity to pediocin PP-1.

The structure of pyogenecin immunity protein, a novel bacteriocin-like immunity protein from Streptococcus pyogenes

“…For each class IIa bacteriocin encoded in a genome there is a one to one relationship between bacteriocin and cognate immunity protein; whereas, in contrast, for each pair of class IIb two-peptide bacteriocins there is a single cognate immunity protein encoded in a genome [ 9 ]. Structures of five immunity proteins have already been solved: ImB2 [ 19 ], EntA-im [ 20 ], PedB [ 21 ], PisI [ 22 ], and Mun-Im [ 23 ], all protective against IIa bacteriocins. As yet, no structures for immunity proteins protective against IIb or IIc bacteriocins have been solved.…”

Nuclear Magnetic Resonance Structure and Mutational Analysis of the Lactococcin A Immunity Protein

“…The four-helix bundle fold found for LciA is similar to the fold observed for the immunity proteins of the pediocin-like bacteriocins. − Interestingly, LciA and the pediocin-like immunity proteins function in a similar manner. They bind to the bacteriocin–man-PTS complex and prevent membrane leakage .…”

“…By generating hybrid immunity proteins in which the C- and N-terminal parts were derived from different immunity proteins, it has been shown that the C-terminal halves of the immunity proteins of the pediocin-like bacteriocins are responsible for recognition of the cognate bacteriocin and receptor complex. , Furthermore, mutational studies of Mun-im and PedB have indicated that the unstructured C-terminal ends of these pediocin-like immunity proteins are important for immunity. To investigate the role of the unstructured C-terminal tail of LciA, point mutations were introduced at the C-terminal end and three truncated variants of LciA were constructed (deletion of 2, 6, or 10 residues from the C-terminal end).…”

“…The amino acid sequence of the lactococcin A immunity protein (LciA) differs considerably from those of the pediocin-like immunity proteins, yet these immunity proteins have a similar self-protection mechanism (i.e., binding to the bacteriocin–man-PTS complex) . The three-dimensional (3D) structures of several immunity proteins that belong to the pediocin-like bacteriocins have been determined, and they all fold into an antiparallel four-helix bundle. − Also, Spy2152, a putative immunity protein produced by Streptococcus pygenes , a strain closely related to LAB, folds into an antiparallel four-helix bundle . In this study, we have determined the 3D structure of LciA and investigated the role of the unstructured C-terminal tail by introducing point mutations and creating truncated versions of LciA.…”

Molecular Characterization of Some Antilisterial Bacteriocin Genes from Enterococcus faecium and Pediococcus pentosaceus

“…1). Many studies have been focused on isolation and genetic manipulations these genes in different strains suitable for industrial applications via genetic engineering [17,18].…”