TY - JOUR T1 - Isolation and purification of a new kalimantacin/batumin-related polyketide antibiotic and elucidation of its biosynthesis gene cluster JF - Chem.Biol. Y1 - 2010 A1 - Wesley Mattheus A1 - Gao,L.J. A1 - Herdewijn,P. A1 - Landuyt,B. A1 - Jan Verhaegen A1 - Masschelein,J. A1 - Volckaert,G. A1 - Lavigne,R. KW - 0 KW - Activity KW - Agent KW - Agents KW - an KW - Anti-Bacterial Agents KW - Antibiotic KW - antibiotics KW - article KW - Base Sequence KW - Belgium KW - biosynthesis KW - chemicals KW - Clinical KW - Cluster KW - Design KW - electronic KW - Engineering KW - function KW - functions KW - gene KW - Gene Knockdown Techniques KW - Genes,Bacterial KW - Genetic KW - genetics KW - genomic KW - Group KW - Hydroxymethylglutaryl-CoA Synthase KW - im KW - inactivation KW - INFECTION KW - infections KW - IS KW - isolation & purification KW - IT KW - journal KW - Laboratories KW - mechanism KW - metabolism KW - MODEL KW - Molecular Sequence Data KW - Multigene Family KW - observed KW - Open Reading Frames KW - organic KW - Organic Chemicals KW - Peptide Synthases KW - pharmacology KW - Polyketide Synthases KW - production KW - Pseudomonas KW - Pseudomonas fluorescens KW - purification KW - region KW - Research KW - Research Support KW - resistance KW - SB - IM KW - staphylococcus KW - strain KW - structure KW - study KW - System KW - technology AB - Kal/bat, a polyketide, isolated to high purity (>95%) is characterized by strong and selective antibacterial activity against Staphylococcus species (minimum inhibitory concentration, 0.05 microg/mL), and no resistance was observed in strains already resistant to commonly used antibiotics. The kal/bat biosynthesis gene cluster was determined to a 62 kb genomic region of Pseudomonas fluorescens BCCM_ID9359. The kal/bat gene cluster consists of 16 open reading frames (ORF), encoding a hybrid PKS-NRPS system, extended with trans-acting tailoring functions. A full model for kal/bat biosynthesis is postulated and experimentally tested by gene inactivation, structural confirmation (using NMR spectroscopy), and complementation. The structural and microbiological study of biosynthetic kal/bat analogs revealed the importance of the carbamoyl group and 17-keto group for antibacterial activity. The mechanism of self-resistance lies within the production of an inactive intermediate, which is activated in a one-step enzymatic oxidation upon export. The genetic basis and biochemical elucidation of the biosynthesis pathway of this antibiotic will facilitate rational engineering for the design of novel structures with improved activities. This makes it a promising new therapeutic option to cope with multidrug-resistant clinical infections VL - 17 CP - 2 U1 - 34022 M3 - http://dx.doi.org/10.1016/j.chembiol.2010.01.014 ER -