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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 an oligopeptide chain made 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.
PBPs normally catalyze the cross-linking of the bacterial cell wall, but they can be permanently inhibited by penicillin and other β-lactam antibiotics. (NAM = N-acetylmuramic acid; NAG = N-acetylglucosamine) [2] Penicillin-binding proteins (PBPs) are a group of proteins that are characterized by their affinity for and binding of penicillin.
N-Acetylglutamic acid is an extracellular metabolite isolated from the prokaryote Rhizobium trifolii that was characterized using many structure determination techniques such as proton nuclear magnetic resonance (1 H NMR) spectroscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectrometry.
Lysozyme (EC 3.2.1.17, muramidase, N-acetylmuramide glycanhydrolase; systematic name peptidoglycan N-acetylmuramoylhydrolase) is an antimicrobial enzyme produced by animals that forms part of the innate immune system.
β-Lactam antibiotics are indicated for the prevention and treatment of bacterial infections caused by susceptible organisms. At first, β-lactam antibiotics were mainly active only against gram-positive bacteria, yet the recent development of broad-spectrum β-lactam antibiotics active against various gram-negative organisms has increased their usefulness.
In particular, peptidoglycan synthesis is vital to cell wall production, and inhibitors of peptidoglycan synthesis have been of clinical interest for targeting bacteria for many decades. [ 24 ] [ 25 ] Furthermore, the periplasm is also relevant to clinical developments by way of its role in mediating the uptake of transforming DNA .
An adenylate moiety is then transferred to form nicotinic acid adenine dinucleotide (NaAD). Finally, the nicotinic acid moiety in NaAD is amidated to a nicotinamide (Nam) moiety, forming nicotinamide adenine dinucleotide. [6] In a further step, some NAD + is converted into NADP + by NAD + kinase, which phosphorylates NAD +. [34]
Ribonucleotide reductase (RNR) is an essential enzyme for all living organisms since it is responsible for the last step in the synthesis of the four deoxyribonucleotides (dNTPs) necessary for DNA replication and repair. [10] The reaction also requires two other proteins: thioredoxin and thioredoxin reductase. Ribonucleoside diphosphate (NDP ...