7phf

Structural highlights

Function

I2N5E8_STRT9 RDMB_STREF Involved in the biosynthesis of the anthracycline aclacinomycin which is an aromatic polyketide antibiotic that exhibits high cytotoxicity and is widely applied in the chemotherapy of a variety of cancers. In vivo and in vitro, RdmB catalyzes the removal of the carboxylic group from the C-10 position of 15-demethoxyaclacinomycin T coupled to hydroxylation at the same C-10 position. It could also catalyze the removal of the carboxylic group at the C-10 position of 15-demethoxy-epsilon-rhodomycin coupled to hydroxylation at the same C-10 position to yield rhodomycin B. The reaction catalyzes by RdmB is intriguing, since the enzyme does not use any of the cofactors usually associated with hydroxylases such as flavins and/or metal ions to activate molecular oxygen.^{[1] [2]} DNRK_STRPE Involved in the biosynthesis of the anthracyclines carminomycin and daunorubicin (daunomycin) which are aromatic polyketide antibiotics that exhibit high cytotoxicity and are widely applied in the chemotherapy of a variety of cancers. In vivo, catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to the 4-O-position of carminomycin to form daunorubicin. In vitro, it also methylates the anthracyclines rhodomycin D (10-carbomethoxy-13-deoxycarminomycin) and 13-deoxy-carminomycin at the 4-hydroxyl position. It is quite specific with respect to the length of the carbohydrate chain at the C7 position, but it can accept substrates with bulky substituent at C10 position.^[3]

References

1. ↑ Wang Y, Niemi J, Airas K, Ylihonko K, Hakala J, Mantsala P. Modifications of aclacinomycin T by aclacinomycin methyl esterase (RdmC) and aclacinomycin-10-hydroxylase (RdmB) from Streptomyces purpurascens. Biochim Biophys Acta. 2000 Jul 14;1480(1-2):191-200. PMID:11004563
2. ↑ Jansson A, Koskiniemi H, Erola A, Wang J, Mantsala P, Schneider G, Niemi J. Aclacinomycin 10-hydroxylase is a novel substrate-assisted hydroxylase requiring S-adenosyl-L-methionine as cofactor. J Biol Chem. 2005 Feb 4;280(5):3636-44. Epub 2004 Nov 17. PMID:15548527 doi:10.1074/jbc.M412095200
3. ↑ Jansson A, Koskiniemi H, Mantsala P, Niemi J, Schneider G. Crystal structure of a ternary complex of DnrK, a methyltransferase in daunorubicin biosynthesis, with bound products. J Biol Chem. 2004 Sep 24;279(39):41149-56. Epub 2004 Jul 24. PMID:15273252 doi:10.1074/jbc.M407081200