Cyclic lipopeptide biological activity

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... 

Leucine-rich cyclic lipopeptides are mainly produced by gram-positive Bacillus spp. and gram-negative Pseudomonas fluorescens. Their structural similarity is not always reflected in their biological activity, and they exhibit some diversity in this regard. 

A lot of interesting lipopeptides, both terms of biological activities and structures, have been discovered from the metabolites of marine-associated organisms. In particular, cyanobacteria produce many kinds of bioactive metabolites including toxins and enzyme inhibitors. Some cyclic lipopeptides from marine-associated organisms have unique structures, which are much different from those of their soil-associated counterparts. For example, the a-diketo structure is in cyclotheonamides 3-amino-6-hydroxy-2-piperidone is in micropeptins, scyptolins and planktopeptins and (2S, 3S, 8S,... 

Cyclic lipopeptide antibiotics contain various kinds of amino acids including unusual amino acids. Many kinds of cyclic lipopeptides were discovered from microorganisms and they often exhibit a wide variety of biological activities such as antimicrobial, antifungal, antitumor, and enzyme inhibitory activities. It is also of considerable interest that the structural similarities do not always reflect any similarity of biological activities in the cyclic lipopeptides. 

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