more information
Search within Results:

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author (up) Kohli, R.M.; Walsh, C.T.; Burkart, M.D. file  url
openurl 
  Title Biomimetic synthesis and optimization of cyclic peptide antibiotics Type Journal Article
  Year 2002 Publication Nature Abbreviated Journal Nature  
  Volume 418 Issue 6898 Pages 658-661  
  Keywords Amino Acid Sequence; Anti-Bacterial Agents/*biosynthesis/*chemical synthesis/pharmacology; Bacteria/drug effects; Biological Products/biosynthesis/chemical synthesis/pharmacology; Catalysis; Cyclization; Erythrocytes/drug effects; Humans; Hydrolysis; Microbial Sensitivity Tests; Molecular Mimicry; Molecular Sequence Data; Peptides, Cyclic/*biosynthesis/*chemical synthesis/pharmacology; Substrate Specificity; Thiolester Hydrolases/metabolism; Tyrocidine/analogs & derivatives/biosynthesis/chemical synthesis/pharmacology  
  Abstract Molecules in nature are often brought to a bioactive conformation by ring formation (macrocyclization). A recurrent theme in the enzymatic synthesis of macrocyclic compounds by non-ribosomal and polyketide synthetases is the tethering of activated linear intermediates through thioester linkages to carrier proteins, in a natural analogy to solid-phase synthesis. A terminal thioesterase domain of the synthetase catalyses release from the tether and cyclization. Here we show that an isolated thioesterase can catalyse the cyclization of linear peptides immobilized on a solid-phase support modified with a biomimetic linker, offering the possibility of merging natural-product biosynthesis with combinatorial solid-phase chemistry. Starting from the cyclic decapeptide antibiotic tyrocidine A, this chemoenzymatic approach allows us to diversify the linear peptide both to probe the enzymology of the macrocyclizing enzyme, TycC thioesterase, and to create a library of cyclic peptide antibiotic products. We have used this method to reveal natural-product analogues of potential therapeutic utility; these compounds have an increased preference for bacterial over eukaryotic membranes and an improved spectrum of activity against some common bacterial pathogens.  
  Call Number Serial 1894  
Permanent link to this record
 

 
Author (up) Shanks, R.M.Q.; Lahr, R.M.; Stella, N.A.; Arena, K.E.; Brothers, K.M.; Kwak, D.H.; Liu, X.; Kalivoda, E.J. file  url
openurl 
  Title A Serratia marcescens PigP homolog controls prodigiosin biosynthesis, swarming motility and hemolysis and is regulated by cAMP-CRP and HexS Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 3 Pages e57634  
  Keywords Bacterial Proteins/*genetics/metabolism; Depsipeptides/*biosynthesis/genetics/pharmacology; Erythrocytes/drug effects; *Gene Expression Regulation, Bacterial; Genetic Complementation Test; Hemolysis/drug effects; Hexosyltransferases/genetics/metabolism; Humans; Membrane Proteins/genetics/metabolism; Movement/drug effects; Mutation; Operon; Prodigiosin/*biosynthesis; Sequence Homology, Amino Acid; Serratia marcescens/*genetics/metabolism; Signal Transduction; Transcription Factors/*genetics/metabolism  
  Abstract Swarming motility and hemolysis are virulence-associated determinants for a wide array of pathogenic bacteria. The broad host-range opportunistic pathogen Serratia marcescens produces serratamolide, a small cyclic amino-lipid, that promotes swarming motility and hemolysis. Serratamolide is negatively regulated by the transcription factors HexS and CRP. Positive regulators of serratamolide production are unknown. Similar to serratamolide, the antibiotic pigment, prodigiosin, is regulated by temperature, growth phase, HexS, and CRP. Because of this co-regulation, we tested the hypothesis that a homolog of the PigP transcription factor of the atypical Serratia species ATCC 39006, which positively regulates prodigiosin biosynthesis, is also a positive regulator of serratamolide production in S. marcescens. Mutation of pigP in clinical, environmental, and laboratory strains of S. marcescens conferred pleiotropic phenotypes including the loss of swarming motility, hemolysis, and severely reduced prodigiosin and serratamolide synthesis. Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS. The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP. This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.  
  Call Number Serial 1612  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations: