bi9b00078_si_001.pdf (1.73 MB)
Identification of YdhV as the First Molybdoenzyme Binding a Bis-Mo-MPT Cofactor in Escherichia coli
journal contribution
posted on 2019-04-04, 00:00 authored by Stefan Reschke, Benjamin R. Duffus, Peer Schrapers, Stefan Mebs, Christian Teutloff, Holger Dau, Michael Haumann, Silke LeimkühlerThe
oxidoreductase YdhV in Escherichia coli has
been predicted to belong to the family of molybdenum/tungsten cofactor
(Moco/Wco)-containing enzymes. In this study, we characterized the
YdhV protein in detail, which shares amino acid sequence homology
with a tungsten-containing benzoyl-CoA reductase binding the bis-W-MPT
(for metal-binding pterin) cofactor. The cofactor was identified to
be of a bis-Mo-MPT type with no guanine nucleotides present, which
represents a form of Moco that has not been found previously in any
molybdoenzyme. Our studies showed that YdhV has a preference for bis-Mo-MPT
over bis-W-MPT to be inserted into the enzyme. In-depth characterization
of YdhV by X-ray absorption and electron paramagnetic resonance spectroscopies
revealed that the bis-Mo-MPT cofactor in YdhV is redox active. The
bis-Mo-MPT and bis-W-MPT cofactors include metal centers that bind
the four sulfurs from the two dithiolene groups in addition to a cysteine
and likely a sulfido ligand. The unexpected presence of a bis-Mo-MPT
cofactor opens an additional route for cofactor biosynthesis in E. coli and expands the canon of the structurally highly
versatile molybdenum and tungsten cofactors.