Structural insight into antibiotic fosfomycin biosynthesis by a mononuclear iron enzyme
Higgins, L.J., Yan, F., Liu, P., Liu, H.W., Drennan, C.L.(2005) Nature 437: 838-844
- PubMed: 16015285 
- DOI: https://doi.org/10.1038/nature03924
- Primary Citation of Related Structures:  
1ZZ6, 1ZZ7, 1ZZ8, 1ZZ9, 1ZZB, 1ZZC - PubMed Abstract: 
The biosynthetic pathway of the clinically important antibiotic fosfomycin uses enzymes that catalyse reactions without precedent in biology. Among these is hydroxypropylphosphonic acid epoxidase, which represents a new subfamily of non-haem mononuclear iron enzymes. Here we present six X-ray structures of this enzyme: the apoenzyme at 2.0 A resolution; a native Fe(II)-bound form at 2.4 A resolution; a tris(hydroxymethyl)aminomethane-Co(II)-enzyme complex structure at 1.8 A resolution; a substrate-Co(II)-enzyme complex structure at 2.5 A resolution; and two substrate-Fe(II)-enzyme complexes at 2.1 and 2.3 A resolution. These structural data lead us to suggest how this enzyme is able to recognize and respond to its substrate with a conformational change that protects the radical-based intermediates formed during catalysis. Comparisons with other family members suggest why substrate binding is able to prime iron for dioxygen binding in the absence of alpha-ketoglutarate (a co-substrate required by many mononuclear iron enzymes), and how the unique epoxidation reaction of hydroxypropylphosphonic acid epoxidase may occur.
Organizational Affiliation: 
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.