Biosynthesis of Streptolidine Involved Two Unexpected Intermediates Produced by a Dihydroxylase and a Cyclase through Unusual Mechanisms1. Issue 7 (21st January 2014)

• Record Type: Journal Article
• Authors: Chang, Chin‐Yuan; Lyu, Syue‐Yi; Liu, Yu‐Chen; Hsu, Ning‐Shian; Wu, Chih‐Chung; Tang, Cheng‐Fong; Lin, Kuan‐Hung; Ho, Jin‐Yuan; Wu, Chang‐Jer; Tsai, Ming‐Daw; Li, Tsung‐Lin
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 7(2014)
• Page Start: 1943
• Page End: 1948
• Publication Date: 2014-01-21
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201307989
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Streptothricin‐F (STT‐F), one of the early‐discovered antibiotics, consists of three components, a β‐lysine homopolymer, an aminosugar <sc>D</sc>‐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 <sc>L</sc>‐Arg into (3<italic>R</italic>, 4<italic>R</italic>)‐(OH)₂‐<sc>L</sc>‐Arg via (3<italic>S</italic>)‐OH‐<sc>L</sc>‐Arg, while OrfR catalyzes an unusual PLP‐dependent elimination/addition reaction cyclizing (3<italic>R</italic>, 4<italic>R</italic>)‐(OH)₂‐<sc>L</sc>‐Arg to the six‐membered (4<italic>R</italic>)‐OH‐capreomycidine. The biosynthetic mystery finally comes to light as the latter product was incorporation into STT‐F by a feeding experiment.</p> </abstract>