Related Experiment Video
Updated: Aug 9, 2026
09:09
Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics
Published on: October 13, 2020
Peptidoglycan hydrolase fusions maintain their parental specificities
David M Donovan1, Shengli Dong, Wes Garrett
1Biotechnology and Germplasm Lab, ANRI, ARS, US Department of Agriculture, Bldg. 230, Room 104, BARC-East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. ddonovan@anri.barc.usda.gov
Applied and Environmental Microbiology
|April 7, 2006
Summary
Novel antimicrobial proteins targeting specific bacteria were developed to combat antibiotic resistance. These fusion proteins show promise for creating mastitis-resistant cattle and as selective agents against human pathogens.
Area of Science:
- Microbiology
- Biotechnology
- Veterinary Science
Background:
- Rising antibiotic resistance necessitates new antimicrobial strategies.
- Peptidoglycan hydrolases (endolysins) offer targeted bacterial lysis, potentially reducing resistance.
- Mastitis in dairy cattle is a significant economic and animal welfare concern.
Purpose of the Study:
- To develop novel antimicrobial fusion proteins for combating bacterial pathogens.
- To assess the efficacy of these proteins in a milk-like environment for potential use in transgenic cattle.
- To evaluate the potential of these antimicrobials against human pathogens and their suitability for reducing broad-spectrum antibiotic use.
Main Methods:
- Fusion of S. agalactiae bacteriophage B30 endolysins (full-length and truncated) with Staphylococcus simulans lysostaphin.
- Testing lytic activity against target pathogens (S. aureus, S. agalactiae) and lactic acid bacteria.
- Assessing activity in a milk-like environment and stability after pasteurization.
- Evaluating expression and cellular effects in cultured mammalian cells.
Main Results:
- Both full-length and truncated endolysin-lysostaphin fusions exhibited lytic activity against streptococcal pathogens and S. aureus.
- The C-terminal SH3b domain of the B30 endolysin was found to be dispensable for lytic activity.
- Fusion proteins were active in a milk-like environment and against some lactic acid bacteria, but inactivated by pasteurization.
- Expression in mammalian cells showed no obvious deleterious effects.
Conclusions:
- Novel endolysin-lysostaphin fusion proteins are effective against key mastitis pathogens and S. aureus.
- These fusion proteins are candidates for developing mastitis-resistant transgenic cattle.
- The antimicrobials show potential for selective targeting of multiple human pathogens, possibly reducing reliance on broad-spectrum antibiotics.
Related Concept Videos
01:28Peptidoglycan Synthesis
Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. It consists of repeating units of two sugars—N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)—linked by β-1,4 glycosidic bonds. These sugar chains are cross-linked by short peptide chains, forming a mesh-like polymer that surrounds the bacterial plasma membrane.Cytoplasmic Phase – Precursor SynthesisPeptidoglycan biosynthesis begins in...
01:23Inhibitors of Gram-positive Cell Wall Synthesis
Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
01:05Proteoglycans
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
01:24Tagging and Fusion Proteins
Proteins are involved in several cellular processes and biochemical reactions. Analyzing a specific protein of interest requires it to be isolated from the other proteins in the cell. This is achieved by overexpressing the specific gene in a suitable host to produce large quantities of the target protein. A tag or label is recombined with the gene to produce a fusion protein containing the target protein and the tag. The tags on these fusion proteins can then be used for easy detection and...
01:57Protein Complexes with Interchangeable Parts
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
01:24Oligosaccharide Assembly
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Multiple sugar molecules that may or may...