Biosynthesis of streptolidine involved two unexpected intermediates produced by a dihydroxylase and a cyclase through unusual mechanisms.Chang, C.Y., Lyu, S.Y., Liu, Y.C., Hsu, N.S., Wu, C.C., Tang, C.F., Lin, K.H., Ho, J.Y., Wu, C.J., Tsai, M.D., Li, T.L.
(2014) Angew.Chem.Int.Ed.Engl. 53: 1943-1948
- PubMed: 24505011
- DOI: 10.1002/anie.201307989
- Primary Citation of Related Structures:  4M23, 4M25, 4M26, 4M2C, 4M2E, 4M2G, 4M2F, 4M2I, 4M2J, 4M2K, 4M2M, 4NE0
- PubMed Abstract:
Streptothricin-F (STT-F), one of the early-discovered antibiotics, consists of three components, a β-lysine homopolymer, an aminosugar D-gulosamine, and an unusual bicyclic streptolidine. The biosynthesis of streptolidine is a long-lasting but unreso ...
Streptothricin-F (STT-F), one of the early-discovered antibiotics, consists of three components, a β-lysine homopolymer, an aminosugar D-gulosamine, and an unusual bicyclic streptolidine. The biosynthesis of streptolidine is a long-lasting but unresolved puzzle. Herein, a combination of genetic/biochemical/structural approaches was used to unravel this problem. The STT gene cluster was first sequenced from a Streptomyces variant BCRC 12163, wherein two gene products OrfP and OrfR were characterized in vitro to be a dihydroxylase and a cyclase, respectively. Thirteen high-resolution crystal structures for both enzymes in different reaction intermediate states were snapshotted to help elucidate their catalytic mechanisms. OrfP catalyzes an Fe(II) -dependent double hydroxylation reaction converting L-Arg into (3R,4R)-(OH)2 -L-Arg via (3S)-OH-L-Arg, while OrfR catalyzes an unusual PLP-dependent elimination/addition reaction cyclizing (3R,4R)-(OH)2 -L-Arg to the six-membered (4R)-OH-capreomycidine. The biosynthetic mystery finally comes to light as the latter product was incorporation into STT-F by a feeding experiment.
Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 115 (Taiwan).