Peptide, bacterial

Daptomycin 1980 Lipo peptide Bacterial Cell Membrane... 

UDP-Af-muramio acid peptide Bacterial cell wall -p UDP (300)... 

LI 14] Li Y., Zirah S., Rebuffat S., Lasso Peptides Bacterial Strategies to Make and Maintain Entangled Scaffolds, Springer-Verlag, 2014. 

Several economically useful peptide antibiotics are produced by members of the bacterial genus bacillus. 

Peptidoplycans (14,16) are the primary component of bacterial cell walls. They consist of a heteropolysaccharide called murein cross-linked with short peptide chains. 

Inhibitors as well as substrates bind in this crevice between the domains. From the numerous studies of different inhibitors bound to serine pro-teinases we have chosen as an illustration the binding of a small peptide inhibitor, Ac-Pro-Ala-Pro-Tyr-COOH to a bacterial chymotrypsin (Figure 11.9). The enzyme-peptide complex was formed by adding a large excess of the substrate Ac-Pro-Ala-Pro-Tyr-CO-NHz to crystals of the enzyme. The enzyme molecules within the crystals catalyze cleavage of the terminal amide group to produce the products Ac-Pro-Ala-Pro-Tyr-COOH and NHs. The ammonium ions diffuse away, but the peptide product remains bound as an inhibitor to the active site of the enzyme. 

Recently, a variety of natural peptides that form transmembrane channels have been identified and characterized. Melittin (Figure 10.35) is a bee venom toxin peptide of 26 residues. The cecropins are peptides induced in Hyalophora cecropia (Figure 10.36) and other related silkworms when challenged by bacterial infections. These peptides are thought to form m-helical aggregates in mem-... 

Figure 6.8 Pendllins are similar to the bacterial peptidogiycan terminal alanylalanine moiety. Because of this similarity, the enzyme transpeptidase recognizes 8-lactam antibiotics as substrate. As a result of this the 8-lactam is incorporated in the peptide chain thereby making peptide-peptide cross-linking impossible. The occurrence of this phenomenon stops the construction of the bacterial cell wall.

Overexpression of apoaequorin (Inouye et al., 1989, 1991). To produce a large quantity of apoaequorin, an apoaequorin expression plasmid piP-HE containing the signal peptide coding sequence of the outer membrane protein A (ompA) of E. coli (Fig. 4.1.12) was constructed and expressed in E. coli. The expressed apoaequorin was secreted into the periplasmic space of bacterial cells and culture medium. The cleaving of ompA took place during secretion thus the... 

An example for proteases are the (3-lactamases that hydrolyse a peptide bond in the essential (3-lactam ring of penicillins, cephalosporins, carbapenems and monobac-tams and, thereby, iireversibly inactivate the diug. 13-lactamases share this mechanism with the penicillin binding proteins (PBPs), which are essential enzymes catalyzing the biosynthesis of the bacterial cell wall. In contrast to the PBPs which irreversibly bind (3-lactams to the active site serine, the analogous complex of the diug with (3-lactamases is rapidly hydrolyzed regenerating the enzyme for inactivation of additional (3-lactam molecules. 

These cells respond to a number of different chemoattractants which have specific and distinct receptors on the membrane surface (for recent reviews see Refs. 3 and 4). Such chemoattractants include N-formylpeptides, which are bacterial peptides, and mediators of inflammation such as leukotriene B4, C5a, and platelet activating factor. 

Good L., Nielsen P.E. Inhibition of translation and bacterial growth by peptide nucleic acid targeted to ribosomal RNA. Proc. Natl Acad. Sci. USA 1998 95 2073-2076. 

---