4M2C image
Entry Detail
PDB ID:
4M2C
Keywords:
Title:
Crystal structure of non-heme iron oxygenase OrfP in complex with Fe and D-Arg
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2013-08-05
Release Date:
2014-06-25
Method Details:
Experimental Method:
Resolution:
2.35 Å
R-Value Free:
0.27
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:L-arginine beta-hydroxylase
Chain IDs:A, B, C, D
Chain Length:364
Number of Molecules:4
Biological Source:Streptomyces lavendulae
Primary Citation
Biosynthesis of streptolidine involved two unexpected intermediates produced by a dihydroxylase and a cyclase through unusual mechanisms.
Angew.Chem.Int.Ed.Engl. 53 1943 1948 (2014)
PMID: 24505011 DOI: 10.1002/anie.201307989

Abstact

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.

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