Parry, Ronald J.2009-06-042009-06-041996Li, Wenying. "Investigation of valanimycin biosynthesis." (1996) Diss., Rice University. <a href="https://hdl.handle.net/1911/16927">https://hdl.handle.net/1911/16927</a>.https://hdl.handle.net/1911/16927The antibiotic valanimycin is an azoxy compound produced by Streptomyces viridifaciens MG456-hF10. Precursor incorporation experiments with (4-$\sp{13}$C) -N-(isobutylamino)serine and $\rm \lbrack\sp{15}N\sb2\rbrack$-N-(isobutylamino)serine suggest that N-(isobutylamino)serine is a specific precursor of valanimycin. Searching for enzymes related to the biosynthetic pathway of valanimycin led to the identification of valine decarboxylase and isobutylamine N-hydroxylase in crude extracts of S. viridifaciens MG456-hF10 cells. Isobutylamine N-hydroxylase requires FAD and NADH for activity. The enzyme was found to consist of two protein components. The A component of isobutylamine N-hydroxylase was partially purified and the B component was purified to homogeneity. The properties of isobutylamine N-hydroxylase were studied. Enzyme replacement experiments suggested that the A component catalyzes the reduction reaction of FAD or FMN with NADH to form FADH$\sb2$ or FMNH$\sb2,$ and that the B component catalyzes the hydroxylation reaction of isobutylamine with the aid of FADH$\sb2$ or FMNH$\sb2,$ and molecular oxygen. Attempts to clone the B component of isobutylamine N-hydroxylase were made. A library of S. viridifaciens MG456-hF10 genomic DNA was constructed using a Lambda DASH II phage vector. The library was screened with a oligonucleotide probe derived from the N-terminal protein sequence of the B component of isobutylamine N-hydroxylase. No gene fragment corresponding to the N-terminal sequence was found. Further screening will be necessary.204 p.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.BiochemistryOrganic chemistryMicrobiologyThesisTHESIS CHEM. 1996 LI