Organophosphonate-degrading PhnZ reveals an emerging family of HD domain mixed-valent diiron oxygenases

Bigna Wörsdörfer, Mahesh Lingaraju, Neela H. Yennawar, Amie K. Boal, Carsten Krebs, J. Martin Bollinger, Maria Eirini Pandelia

18 Scopus citations

Abstract

The founding members of the HD-domain protein superfamily are phosphohydrolases, and newly discovered members are generally annotated as such. However, myo-inositol oxygenase (MIOX) exemplifies a second, very different function that has evolved within the common scaffold of this superfamily. A recently discovered HD protein, PhnZ, catalyzes conversion of 2-amino-1-hydroxyethylphosphonate to glycine and phosphate, culminating a bacterial pathway for the utilization of environmentally abundant 2-aminoethylphosphonate. Using Mössbauer and EPR spectroscopies, X-ray crystallography, and activity measurements, we show here that, like MIOX, PhnZ employs a mixed-valent FeII/FeIII cofactor for the O2-dependent oxidative cleavage of its substrate. Phylogenetic analysis suggests that many more HD proteins may catalyze yet-unknown oxygenation reactions using this hitherto exceptional FeII/FeIII cofactor. The results demonstrate that the catalytic repertoire of the HD superfamily extends well beyond phosphohydrolysis and suggest that the mechanism used by MIOX and PhnZ may be a common strategy for oxidative C-X bond cleavage.

Original languageEnglish (US)
Pages (from-to)18874-18879
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number47
DOIs
Publication statusPublished - Nov 19 2013

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