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A two‐component, multimeric endolysin encoded by a single gene
Author(s) -
Proença Daniela,
Velours Christophe,
Leandro Clara,
Garcia Miguel,
Pimentel Madalena,
SãoJosé Carlos
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12857
Subject(s) - lysin , biology , bacteriophage , bacterial cell structure , protein subunit , biochemistry , enzyme , gene , bacteria , genetics , escherichia coli
Summary Bacteriophage endolysins are bacterial cell wall degrading enzymes whose potential to fight bacterial infections has been intensively studied. Endolysins from Gram‐positive systems are typically described as monomeric and as having a modular structure consisting of one or two N ‐terminal catalytic domains ( CD s) linked to a C ‐terminal region responsible for cell wall binding ( CWB ). We show here that expression of the endolysin gene lys170 of the enterococcal phage F 170/08 results in two products, the expected full length endolysin ( L ys170 FL ) and a C ‐terminal fragment corresponding to the CWB domain ( CWB 170). The latter is produced from an in‐frame, alternative translation start site. Both polypeptides interact to form the fully active endolysin. Biochemical data strongly support a model where L ys170 is made of one monomer of L ys170 FL associated with up to three CWB 170 subunits, which are responsible for efficient endolysin binding to its substrate. Bioinformatics analysis indicates that similar secondary translation start signals may be used to produce and add independent CWB 170‐like subunits to different enzymatic specificities. The particular configuration of endolysin L ys170 uncovers a new mode of increasing the number of CWB motifs associated to CD modules, as an alternative to the tandem repetition typically found in monomeric cell wall hydrolases.