4M26: Crystal Structure Of Non-heme Iron Oxygenase Orfp In Complex With Fe, Succinate, And (3s)-hydroxy-l-arg

Citation:
Abstract
Streptothricin-F (STT-F), one of the early-discovered antibiotics, consists of three components, a beta-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.
PDB ID: 4M26Download
MMDB ID: 120973
PDB Deposition Date: 2013/8/5
Updated in MMDB: 2014/06
Experimental Method:
x-ray diffraction
Resolution: 2.02  Å
Source Organism:
Similar Structures:
Biological Unit for 4M26: dimeric; determined by author and by software (PISA)
Molecular Components in 4M26
Label Count Molecule
Proteins (2 molecules)
2
L-arginine Beta-hydroxylase
Molecule annotation
Chemicals (5 molecules)
1
3
2
2
* Click molecule labels to explore molecular sequence information.

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