From lipopeptides

Jia D, Tao K, Wang J, Wang C, Zhao W, Yaseen M, et al. D3mamic adsorption and structure of interfacial bilayers adsorbed from lipopeptide surfactants at the hydrophihc silicon/water interface effects of the headgroup length. Langmuir 2011 27 8798-809. 

Madonna, A. J. Voorhees, K. J. Tarenko, N. I. Laiko, V. V. Doroshenko, V. M. Detection of cychc lipopeptide biomarkers from Bacillus species using atmospheric... 

Miao, V., Brost, R., Chappie, J. et al. (2006) The lipopeptide antibiotic A54145 biosynthetic gene cluster from Streptomyces fradiae. Journal of Industrial Microbiology Biotechnology, 33, 129. 

One of the most characteristic features of FRET is its sensitive dependency on the fluorophore distance. This is advantageously used to evaluate structures and conformational changes of peptides, glycopeptides, and proteins among other molecules [164-166], The conformational change of the lipopeptide antibiotic daptomycin from an inactive linear form to a biological active cyclic form... 

New insights into the analysis of hydrophobically post-translational modified proteins could be achieved by the construction of lipidated proteins in a combination of bioorganic synthesis of activated lipopeptides and bacterial expression of the protein backbone (Fig. 19). The physico-chemical properties of such artificial lipoproteins differ substantially from those of the corresponding lipopeptides. The pronounced dominance of the hydrophilic protein moiety (e.g., for the Ras protein 181 amino acids) over a short lipopeptide with one or two hydrophobic modifications provides solubility up to 10 4 mol/1, while the biotinylated or fluorescence labeled lipopeptides exhibit low solubility in aqueous solutions and can be applied in the biophysical experiments only in vesicle integrated form or dissolved in organic solvent. 

The results summarized above were obtained by using fluorescence based assays employing phospholipid vesicles and fluorescent labeled lipopeptides. Recently, surface plasmon resonance (SPR) was developed as new a technique for the study of membrane association of lipidated peptides. Thus, artificial membranes on the surface of biosensors offered new tools for the study of lipopeptides. In SPR (surface plasmon resonance) systemsI713bl changes of the refractive index (RI) in the proximity of the sensor layer are monitored. In a commercial BIAcore system1341 the resonance signal is proportional to the mass of macromolecules bound to the membrane and allows analysis with a time resolution of seconds. Vesicles of defined size distribution were prepared from mixtures of lipids and biotinylated lipopeptides by extruder technique and fused with a alkane thiol surface of a hydrophobic SPR sensor. 

Fig. 9.5 Induction of THP-1 cells by 220-CNTs and 825-CNTs. The diacylated lipopeptide FSL-1 was used as a positive control (Gong et al., 2000. With permission from The Royal Society of Chemistry)...

Figure 3 Design of a diepitope liposomal construct. Small unilamellar liposomes (PC/PG/Chol 55/25/50 molar ratio diameter 100nm) containing 10mol% of bromo-acetyl l,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine and 10mol% of the thiol-reactive lipopeptide adjuvant anchor Pam3CysAlaGly-Mal were reacted, at 25°C successively at pH 6.5, with the T-helper epitope QYI, derivatized with a C-linker at its N-terminus, followed at pH 9.0 by the B-epitope TPE derivatized with a CG linker at its N-terminus. Abbreviations PC, phosphatidylcholine PE, phosphatidylethanolamine SUV, small unilamellar vesicles. Source From Refs. 11, 20, 21.

The two examples from our work we are going to describe below are the design and study of liposomal diepitope constructs combining either (i) B and T-helper (Th) peptide epitopes, which induced particularly powerful humoral responses (21) (Fig. 3) or (ii) CTL and Th epitopes, which provided a powerful antitumor vaccine (74) (Fig. 4). For the production of these constructs we have conjugated peptides that contain a cysteine residue either at the N- or C-terminus, to the surface of preformed liposomes by reaction with thiol reactive functionalized phospholipids and/or PamaCys lipopeptide anchors (Fig. 2). To that end, we have developed strategies that give, in aqueous media, high... 

Conlan JW, et al. Immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various Archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen. Listeria monocytogenes. Vaccine 2001 19 3509. 

Aretz W, Meiwes J, Seibert Q Vobis Ci Wink J. (2000) Frinlimicins novel lipopeptide antibiotics with peptidoglycan synthesis inhibiting activity from Actinoplanes Friuliensis sp nov. J Antibiot 53 807-815. 

Naimochelin C (Fig. 15, 54) from the myxobacterium Nannocystis exedens contains two L-Lys and two ( )-cinnamic acid units. The reported mono- and di-methyl esters (nannochelin B and A) may be artifacts from the work-up (198). A synthesis is described (29) (see Sect. 8.4). The ochrobactins (Fig. 15,55) isolated from the sea-shore bacterium Ochrobactrum sp. (214) with the spacer L-lysine are membrane active due to the fatty acid residues (saturated Cg and (2 )-unsaturated Cg and Cio) cf. lipopeptidic siderophores in Sect. 2.8. 

A novel cyclic lipopeptide antibiotic was isolated from cultures of Strep-tomyces roseosporus grown in the presence of decanioc acid. Daptomycin interacts with the bacterial cell membrane and interferes with membrane potential.Unlike polymyxin B, daptomycin can target majority of clinically relevant Gram-positive pathogens. 

Additionally, a vast array of natural lipopeptides with remarkable structural diversity is produced by microorganisms living in different habitats, from aquatic to terrestrial environments. These products are not gene encoded, but are synthesized nonribosomally by large multifunctional enzymes, the peptide synthetases. 6"8 ... 

Bonnard, I., Rolland, M., Francisco, C, and Banaigs, B. (1997). Total structure and biological properties of laxaphycins A and B, cyclic lipopeptides from the marine cyanobacterium Lyngbya majuscula. Lett. Pept. Sci. 4, 289-292. 

MacMillan, J. B., Emst-Russell, M. A., de Ropp, J. S., and Molinski, T. F. (2002). Lobocycla-mides A-C, lipopeptides from a cryptic cyanobacterial mat containing Lyngbya confervoides. J. Org. Chem. 67, 8210-8215. 

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