We propose to continue our studies of antibiotic biosynthesis, and will focus on the secondary metabolism of amino acids and of glucose. With the former our emphasis will be on the generation of Beta-hydroxy-Alpha-amino acids and of Beta-amino acids as biosynthetic intermediates. This work will include further experiments on streptothricin F, blasticidin, negamycin and 3-epideoxynegamycin, and will be expanded to include the biogenetically relevant metabolites elastatinal, AT-125, and chloramphenicol in order to test our hypotheses on the formation and utilization of Beta-hydroxy amino acids. We will primarily use the stable isotopes 13C, 2H, 15N, and 18O and they will be detected by NMR spectroscopic techniques. A number of labeled compounds that will be synthesized will be used in more than one of these projects. Analysis of the isotope labeling patterns will again use our 15N/13C NMR spin coupling technique, will explore the utility of our new 1H/2H COSY technique for editing complex 2H NMR spectra, and will explore the utility of 3H NMR and of high resolution FAB mass spectrometry for locating isotope labels in complex metabolites. Our investigations will increase our understanding of which chemical reactions are available in Nature and how they can be linred to produce complex structures. They may also provide the opportunity to produce new analogs, also with antibiotic activity, by redirecting the microorganisms' biosynthetic apparatus to use modified precursors.
