A bacteriophage, also known informally as a phage, is a virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν, meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.
Peptidoglycan or murein is a polymer consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane of most bacteria, forming the cell wall. The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is a peptide chain of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer. Peptidoglycan serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
Methicillin, also known as meticillin, is a narrow-spectrum β-lactam antibiotic of the penicillin class.
Phage therapy, viral phage therapy, or phagotherapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections. Bacteriophages, known as phages, are a form of virus. Phages attach to bacterial cells, and inject a viral genome into the cell. The viral genome effectively replaces the bacterial genome, halting the bacterial infection. The bacterial cell causing the infection is unable to reproduce, and instead produces additional phages. Phages are very selective in the strains of bacteria they are effective against. Advantages include reduced side-effects and reduced risk of the bacterium's developing resistance. Disadvantages include the difficulty of finding an effective phage for a particular infection. However, virulent phages can be isolated much more easily than other compounds and natural products. In addition to this, development of standardized manufacturing processes would make lab to clinic delivery of phages much quicker.
Ceragenix Pharmaceuticals, Inc. is a biopharmaceutical company headquartered in Denver, Colorado that develops prescription therapies based on a platform of proprietary surface active technologies—skin Barrier Repair Technology (BRT) and Cerageninis, a new class of broad spectrum anti-infectives. The company discovers, develops and commercializes anti-infective drugs based on its proprietary class of compounds, Ceragenins. Active against a range of gram positive and gram negative bacteria, these agents are being developed as anti-infective medical device coatings and as therapeutics for antibiotic-resistant organisms.
N-Acetylmannosamine is a hexosamine monosaccharide. It is a neutral, stable naturally occurring compound. N-Acetylmannosamine is also known as N-Acetyl-D-mannosamine monohydrate,, N-Acetyl-D-mannosamine which can be abbreviated to ManNAc or, less commonly, NAM). ManNAc is the first committed biological precursor of N-acetylneuraminic acid. Sialic acids are the negatively charged, terminal monosaccharides of carbohydrate chains that are attached to glycoproteins and glycolipids (glycans).
Lysins, also known as endolysins or murein hydrolases, are hydrolytic enzymes produced by bacteriophages in order to cleave the host's cell wall during the final stage of the lytic cycle. Lysins are highly evolved enzymes that are able to target one of the five bonds in peptidoglycan (murein), the main component of bacterial cell walls, which allows the release of progeny virions from the lysed cell. Cell-wall-containing Archaea are also lysed by specialized pseudomurein-cleaving lysins, while most archaeal viruses employ alternative mechanisms. Similarly, not all bacteriophages synthesize lysins: some small single-stranded DNA and RNA phages produce membrane proteins that activate the host's autolytic mechanisms such as autolysins.
The enzyme UDP-glucose 4-epimerase, also known as UDP-galactose 4-epimerase or GALE, is a homodimeric epimerase found in bacterial, fungal, plant, and mammalian cells. This enzyme performs the final step in the Leloir pathway of galactose metabolism, catalyzing the reversible conversion of UDP-galactose to UDP-glucose. GALE tightly binds nicotinamide adenine dinucleotide (NAD+), a co-factor required for catalytic activity.
In enzymology, an UDP-N-acetylglucosamine 2-epimerase is an enzyme that catalyzes the chemical reaction
In enzymology, N-acetylglucosamine-6-phosphate deacetylase (EC 3.5.1.25), also known as GlcNAc-6-phosphate deacetylase or NagA, is an enzyme that catalyzes the deacetylation of N-acetylglucosamine-6-phosphate (GlcNAc-6-P) to glucosamine-6-phosphate (GlcN-6-P):
Bifunctional UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase is an enzyme that in humans is encoded by the GNE gene.
Ribostamycin is an aminoglycoside-aminocyclitol antibiotic isolated from a streptomycete, Streptomyces ribosidificus, originally identified in a soil sample from Tsu City of Mie Prefecture in Japan. It is made up of 3 ring subunits: 2-deoxystreptamine (DOS), neosamine C, and ribose. Ribostamycin, along with other aminoglycosides with the DOS subunit, is an important broad-spectrum antibiotic with important use against human immunodeficiency virus and is considered a critically important antimicrobial by the World Health Organization., Resistance against aminoglycoside antibiotics, such as ribostamycin, is a growing concern. The resistant bacteria contain enzymes that modify the structure through phosphorylation, adenylation, and acetylation and prevent the antibiotic from being able to interact with the bacterial ribosomal RNAs.
Cephalosporins are a broad class of bactericidal antibiotics that include the β-lactam ring and share a structural similarity and mechanism of action with other β-lactam antibiotics. The cephalosporins have the ability to kill bacteria by inhibiting essential steps in the bacterial cell wall synthesis which in the end results in osmotic lysis and death of the bacterial cell. Cephalosporins are widely used antibiotics because of their clinical efficiency and desirable safety profile.
In molecular biology, UDP-3-O-N-acetylglucosamine deacetylase, EC 3.5.1.-, is a bacterial enzyme involved in lipid A biosynthesis.
Enzybiotics are an experimental antibacterial therapy first described by Nelson, Loomis, and Fischetti. The term is derived from a combination of the words “enzyme” and “antibiotics.” Enzymes have been extensively utilized for their antibacterial and antimicrobial properties. Proteolytic enzymes called endolysins have demonstrated particular effectiveness in combating a range of bacteria and are the basis for enzybiotic research. Endolysins are derived from bacteriophages and are highly efficient at lysing bacterial cells. Enzybiotics are being researched largely to address the issue of antibiotic resistance, which has allowed for the proliferation of drug-resistant pathogens posing great risk to animal and human health across the globe.
In molecular biology, VanY are protein domains found in enzymes named metallopeptidases. They are vital to bacterial cell wall synthesis and antibiotic resistance.
UDP-N-acetylglucosamine 2-epimerase (hydrolysing) (EC 3.2.1.183, UDP-N-acetylglucosamine 2-epimerase, GNE (gene), siaA (gene), neuC (gene)) is an enzyme with systematic name UDP-N-acetyl-alpha-D-glucosamine hydrolase (2-epimerising). This enzyme catalyses the following chemical reaction
Lipid II is a precursor molecule in the synthesis of the cell wall of bacteria. It is a peptidoglycan, which is amphipathic and named for its bactoprenol hydrocarbon chain, which acts as a lipid anchor, embedding itself in the bacterial cell membrane. Lipid II must translocate across the cell membrane to deliver and incorporate its disaccharide-pentapeptide "building block" into the peptidoglycan mesh. Lipid II is the target of several antibiotics.
OBPgp279 is an endolysin that hydrolyzes peptidoglycan, a major constituent in bacterial membrane. OBPgp279 is found in Pseudomonas fluorescens phage OBP, which belongs in the Myoviridae family of bacteriophages. Because of its role in hydrolyzing the peptidoglycan layer, OBPgp279 is a key enzyme in the lytic cycle of the OBP bacteriophage; it allows the bacteriophage to lyse its host internally to escape. Unlike other endolysins, OBPgp279 does not rely on holins to perforate the inner bacterial membrane in order to reach the peptidoglycan layer. Although OBPgp279 is not a well-studied enzyme, it has garnered interest as a potential antibacterial protein due to its activity against multidrug-resistant gram-negative bacteria.
Although cell wall carbohydrates are ideal immunotherapeutic targets due to their abundance in bacteria and high level of conservation, their poor immunogenicity compared with protein targets complicates their use for the development of protective antibodies. A lysibody is a chimeric antibody in which the Fab region is the binding domain from a bacteriophage lysin, or the binding domain from an autolysin or bacteriocin, all of which bind to bacterial cell wall carbohydrate epitopes. This is linked to the Fc of Immunoglobulin G (IgG). The chimera forms a stable homodimer held together by hinge-region disulfide bonds. Thus, lysibodies are homodimeric hybrid immunoglobulin G molecules that can bind with high affinity and specificity to a carbohydrate substrate in the bacterial cell wall peptidoglycan. Lysibodies behave like authentic IgG by binding at high affinity to their bacterial wall receptor, fix complement and therefore promote phagocytosis by macrophages and neutrophils, protecting mice from infection in model systems. Since cell wall hydrolases, autolysins and bacteriocins are ubiquitous in nature, production of lysibodies specific for difficult to treat pathogenic bacteria is possible.
