Use of Bacteriophage Cell Wall-Binding Proteins for Rapid Diagnostics of Listeria

2014 ◽  
pp. 141-156 ◽  
Author(s):  
Mathias Schmelcher ◽  
Martin J. Loessner
Keyword(s):  
Cell Wall ◽  
Binding Proteins ◽  
Rapid Diagnostics ◽  
Cell Wall Binding

scholarly journals A Putative Amidase Endolysin Encoded by Clostridium perfringens St13 Exhibits Specific Lytic Activity and Synergizes with the Muramidase Endolysin Psm

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 245
Author(s):  
Hiroshi Sekiya ◽  
Maho Okada ◽  
Eiji Tamai ◽  
Toshi Shimamoto ◽  
Tadashi Shimamoto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clostridium Perfringens ◽  
Antimicrobial Agents ◽  
Catalytic Domain ◽  
Food Poisoning ◽  
Binding Activity ◽  
Lytic Activity ◽  
Intestinal Bacterium ◽  
Terminal Domain ◽  
Cell Wall Binding

Clostridium perfringens is an often-harmful intestinal bacterium that causes various diseases ranging from food poisoning to life-threatening fulminant disease. Potential treatments include phage-derived endolysins, a promising family of alternative antimicrobial agents. We surveyed the genome of the C. perfringens st13 strain and identified an endolysin gene, psa, in the phage remnant region. Psa has an N-terminal catalytic domain that is homologous to the amidase_2 domain, and a C-terminal domain of unknown function. psa and gene derivatives encoding various Psa subdomains were cloned and expressed in Escherichia coli as N-terminal histidine-tagged proteins. Purified His-tagged full-length Psa protein (Psa-his) showed C. perfringens-specific lytic activity in turbidity reduction assays. In addition, we demonstrated that the uncharacterized C-terminal domain has cell wall-binding activity. Furthermore, cell wall-binding measurements showed that Psa binding was highly specific to C. perfringens. These results indicated that Psa is an amidase endolysin that specifically lyses C. perfringens; the enzyme’s specificity is highly dependent on the binding of the C-terminal domain. Moreover, Psa was shown to have a synergistic effect with another C. perfringens-specific endolysin, Psm, which is a muramidase that cleaves peptidoglycan at a site distinct from that targeted by Psa. The combination of Psa and Psm may be effective in the treatment and prevention of C. perfringens infections.

scholarly journals Escherichia coli Mutants Lacking All Possible Combinations of Eight Penicillin Binding Proteins: Viability, Characteristics, and Implications for Peptidoglycan Synthesis

1999 ◽  
Vol 181 (13) ◽  
pp. 3981-3993 ◽  
Author(s):  
Sylvia A. Denome ◽  
Pamela K. Elf ◽  
Thomas A. Henderson ◽  
David E. Nelson ◽  
Kevin D. Young
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Binding Proteins ◽  
Kanamycin Resistance ◽  
Open Reading Frames ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Kanamycin Resistance Cassette ◽  
Genes Encoding

ABSTRACT The penicillin binding proteins (PBPs) synthesize and remodel peptidoglycan, the structural component of the bacterial cell wall. Much is known about the biochemistry of these proteins, but little is known about their biological roles. To better understand the contributions these proteins make to the physiology ofEscherichia coli, we constructed 192 mutants from which eight PBP genes were deleted in every possible combination. The genes encoding PBPs 1a, 1b, 4, 5, 6, and 7, AmpC, and AmpH were cloned, and from each gene an internal coding sequence was removed and replaced with a kanamycin resistance cassette flanked by two ressites from plasmid RP4. Deletion of individual genes was accomplished by transferring each interrupted gene onto the chromosome of E. coli via λ phage transduction and selecting for kanamycin-resistant recombinants. Afterwards, the kanamycin resistance cassette was removed from each mutant strain by supplying ParA resolvase in trans, yielding a strain in which a long segment of the original PBP gene was deleted and replaced by an 8-bpres site. These kanamycin-sensitive mutants were used as recipients in further rounds of replacement mutagenesis, resulting in a set of strains lacking from one to seven PBPs. In addition, thedacD gene was deleted from two septuple mutants, creating strains lacking eight genes. The only deletion combinations not produced were those lacking both PBPs 1a and 1b because such a combination is lethal. Surprisingly, all other deletion mutants were viable even though, at the extreme, 8 of the 12 known PBPs had been eliminated. Furthermore, when both PBPs 2 and 3 were inactivated by the β-lactams mecillinam and aztreonam, respectively, several mutants did not lyse but continued to grow as enlarged spheres, so that one mutant synthesized osmotically resistant peptidoglycan when only 2 of 12 PBPs (PBPs 1b and 1c) remained active. These results have important implications for current models of peptidoglycan biosynthesis, for understanding the evolution of the bacterial sacculus, and for interpreting results derived by mutating unknown open reading frames in genome projects. In addition, members of the set of PBP mutants will provide excellent starting points for answering fundamental questions about other aspects of cell wall metabolism.

scholarly journals The structure of Rv3717 reveals a novel amidase fromMycobacterium tuberculosis

2013 ◽  
Vol 69 (12) ◽  
pp. 2543-2554 ◽  
Author(s):  
Atul Kumar ◽  
Sanjiv Kumar ◽  
Dilip Kumar ◽  
Arpit Mishra ◽  
Rikeshwer P. Dewangan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bartonella Henselae ◽  
General Mechanism ◽  
Isolation And Identification ◽  
Cell Wall Binding ◽  
New Family ◽  
A Cell ◽  
Sad Phasing ◽  
Cell Wall Binding Domain ◽  
Net Positive Charge

BacterialN-acetylmuramoyl-L-alanine amidases are cell-wall hydrolases that hydrolyze the bond betweenN-acetylmuramic acid and L-alanine in cell-wall glycopeptides. Rv3717 ofMycobacterium tuberculosishas been identified as a unique autolysin that lacks a cell-wall-binding domain (CBD) and its structure has been determined to 1.7 Å resolution by the Pt-SAD phasing method. Rv3717 possesses an α/β-fold and is a zinc-dependent hydrolase. The structure reveals a short flexible hairpin turn that partially occludes the active site and may be involved in autoregulation. This type of autoregulation of activity of PG hydrolases has been observed inBartonella henselaeamidase (AmiB) and may be a general mechanism used by some of the redundant amidases to regulate cell-wall hydrolase activity in bacteria. Rv3717 utilizes its net positive charge for substrate binding and exhibits activity towards a broad spectrum of substrate cell walls. The enzymatic activity of Rv3717 was confirmed by isolation and identification of its enzymatic products by LC/MS. These studies indicate that Rv3717, anN-acetylmuramoyl-L-alanine amidase fromM. tuberculosis, represents a new family of lytic amidases that do not have a separate CBD and are regulated conformationally.

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