title: Analysis of five tylosin biosynthetic genes from the tyllBA region of the Streptomyces fradiae genome.
abstract: The tyllBA region of the tylosin biosynthetic gene cluster of Streptomyces fradiae contains at least five open reading frames (ORFs). ORF1 (tylI) encodes a cytochrome P450 and mutations in this gene affect macrolide ring hydroxylation. The product of ORF2 (tylB) belongs to a widespread family of proteins whose functions are speculative, although tylB mutants are defective in the biosynthesis or addition of mycaminose during tylosin production. ORFs 3 and 4 (tylA1 and tylA2) encode delta TDP-glucose synthase and delta TDP-glucose dehydratase, respectively, enzymes responsible for the first two steps common to the biosynthesis of all three deoxyhexose sugars of tylosin via the common intermediate, delta TDP-4-keto, 6-deoxyglucose. ORF5 encodes a thioesterase similar to one encoded in the erythromycin gene cluster of Saccharopolyspora erythraea.
authors.affiliation: Department of Biochemistry, University of Leicester, UK.
authors.forename: L A
authors.initials: LA
authors.lastname: Merson-Davies
authors.forename: E
authors.initials: E
authors.lastname: Cundliffe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D006460:Hemolysin Proteins / Q000235:genetics; D006836:Hydro-Lyases / Q000235:genetics; D008359:Mannose-6-Phosphate Isomerase; D008969:Molecular Sequence Data; D009713:Nucleotidyltransferases / Q000235:genetics; D016366:Open Reading Frames; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013302:Streptomyces / Q000235:genetics*; D015645:Tylosin / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D006460:Hemolysin Proteins; C090673:TlyB protein, Brachyspira hyodysenteriae; D009713:Nucleotidyltransferases; C085243:dTDP-D-glucose synthase; D006836:Hydro-Lyases; C022771:dTDPglucose 4,6-dehydratase; D008359:Mannose-6-Phosphate Isomerase; D015645:Tylosin