A nitrile hydratase for cyanopyridines... (but it prefers aliphatic nitriles)

There has been a recent paper in Journal of Molecular Catalysis B on a nitrilase that converted cyanopyridines. This enzyme came from a strain of Pseudomonas putida. There is also a recent paper in the same journal entitled “Discovery of a new Fe-type nitrile hydratase efficiently hydrating aliphatic and aromatic nitriles by genome mining” by Xiaolin Peia, Lirong Yang, Gang Xu, Qiuyan Wang and Jianping Wu.which describes a nitrile hydratase, this time, from a Pseudomonas putida strain (F1) which they have shown to be able to turn over 3-cyanopyridine in a 1L fed batch reactor. Their activity data suggests it actually prefers aliphatic nitriles: acrylonitrile rates as 941 U/mg and valeronitrile as 535 U/mg as compared to 3-cyanopyridine at 26 U/mg. They describe how it was cloned into E. coli, needing the inclusion of an activator protein to get activity. They also include a nice phylogenetic tree showing the spread of known iron type NHases... plenty of examples in the Rhodococcus but spreading outwards into Pseudomonas.

PDBs on a phylogenetic tree

There is a figure of a phylogenetic tree in the Prasad Balla review from 2010 which gives a separation of the different currently known sequences. I have very roughly stitched the tree together from the two parts given on two pages of the review and then I have dropped on top the rough positions of the three most distinct cobalt centred PDB files (1V29, 1UGP and 3QXE) and one of the rhodococcus iron centred files (1AHJ). It is interesting that workers seem to be producing PDB files solely from the right hand half of this tree.