Nitrilases thaliana

Figure 8.14 Preparation of (S)-3-cyano-5-methyl hexanoic acid from isobutylsuccinonitrile using a regio- and stereo-selective nitrilase from AtNitl Arabidopsis thaliana...

Nitrilase was initially discovered in plants as an enzyme involved in the biosynthesis of the plant hormone indole-3-acetic acid (IAA) [74,75], Recently, four genes of nitrilases (belonging to arylacetonitrilase) involved in the IAA biosynthesis have been cloned and characterized from Arabidopsis thaliana [76-78], After the discovery of the plant nitrilase in 1964, various nitrilases were purified and characterized [41], Nitrilases are roughly classified into three major categories according to substrate specificity (i) aromatic nitrilase, which acts on aromatic or heterocyclic nitriles (ii) aliphatic nitrilase, which acts on aliphatic nitriles (iii) arylacetonitrilase, which acts on arylacetonitriles. These three types... 

KUTZ, A., MULLER, A., HENNING, P KAISER, W.M., PIOTROWSK1, M WEILER, E.M., A role for nitrilase 3 in the regulation of root morphology in sulphur-starving Arabidopsis thaliana., PlcmtJ., 2002,30,95-106. 

Bartel, B. and Fink, G.R. 1994. Differential regulation of an auxin-producing nitrilase gene family in Arabidopsis thaliana. Proceedings of the National Academy of Science USA, 91 6649-53. 

Effenberger, F. and Oswald, S. 2001a. Enantioselective hydrolysis of (R,S)-2-fluoroary-lacetonitriles using nitrilase from Arabidopsis thaliana. Tetrahedron Asymmetry, 12 279-85. 

Piotrowski, M., Schonfelder, S., and Weiler, W.E. 2001. The Th Arabidopsis thaliana isogene NIT4 and its orthologs in tobacco encode 3-cyano-l-alanine hydratase/nitrilase. Journal of Biological Chemistry, 276 2616-21. 

Figure 2. Resolution of racemic 2-fluoroarylnitriles using nitrilase from Arabidopsis thaliana (14).

I, 3-dienyl)-acrylonitrile (the enzymatic oxidation product of cinnamonitrile) could be hydrolyzed by nitrilases from a Rhodococcus strain and Arabidopsis thaliana (AtNitl) [79]. A combination of CBDO and a nitrilase in the same host could provide a new and efficient route to a previously undescribed class of acids and chiral ds-diols, which could not be perceived by traditional chemical methods (Figure 11.15). 

There are many examples of nitrilase-catalyzed reactions in which amides form a considerable amount of the reaction products, such as the transformations of acrylonitrile analogs and a-fluoroarylacetonitriles by nitrilase 1 from Arabidopsis thaliana [17], the conversion of p-cyano-L-alanine into a mixture of L-asparagine and L-aspartic acid by nitrilase 4 from the same organism [18] or the transformations of mandelonitrile by nitrilase from Pseudomonas jhiorescens [19] or some fungi [8], Moreover, formamide is the only product of the cyanide transformation by cyanide hydratase. Therefore, this enzyme was classified as a lyase (EC 4.2.1.66), although it is closely related to nitrilases, as far as its aa sequence and reaction mechanism are concerned [3]. 

Nitrilases in plants are comprised of two subtypes with different biological functions. The first subtype involves nitrilases exhibiting mostly over 70% identity levels to the biochemically characterized nitrilases 1-3 from A. thaliana, which act on substrates such as 3-phenylpropionitrile, allylcyanide, or indole-3-acetonitrile. They seem to be specific for Brassicaceae, which is in accordance with their preference for the nitriles endogeneous in this family or structurally similar to them [22]. They are able to produce plant auxins such as indole-3-acetic acid but the role of this pathway in vivo is not fully understood [21]. 

The region downstream of the catalytic Cys also allows nitrilases and cyanide hydratases to be distinguished relatively successfully. The experimentally confirmed cyanide hydratases contain an Asn residue at position 3 downstream of the catalytic Cys [5, 6], whereas most of the characterized nitrilases carry a His at this position except for a few enzymes (from A. thaliana and Klebsiella ozaenae with an Asn at the corresponding site [3]). 

Even more striking is the ability to discriminate diastereomers of a,p-unsatu-rated nitriles nitrilase AtNITl from Arahidopsis thaliana resolved a series of approximately 60 40 E/Z mixtures of 22 into configurationally pure Z-nitriles 23 and E-acids 24 (Scheme 9.6) [34]. This synthetic method thus represents a... 

Resolution of diastereomeric vinyl nitriles using a nitrilase from A. thaliana [34]. 

F. Effenberger, Acids Selective hydrolysis of aliphatic dinitriles to monocarboxylic acids by a nitrilase from Arabidopsis thaliana, S. Ofiwald, Synthesis 12 (2001) 1866-1872. 

F. Effenberger, S. Osswald, (E)-Selective hydrolysis of (E,Z)-a,p-unsaturated nitriles by the recombinant nitrilase AtNlTl from Arabidopsis thaliana, Tetrahedron A.symmetry 12 (2001)... 

The nitrilase NITl in A. thaliana, which was overproduced in E. coli, proved to have a wide S5mthetic use, its products being aliphatic and arylaliphatic carboxylic acids or amides depending on the structure of the substrate [81]. A similar nitrilase (ZmNIT2) was characterized in Zea mays (maize) [82]. This enzyme also... 

Vorwerk, S., Biemacki, S., Hillebrand, H., Janzik, L, Muller, A., WeUer, E.W., and Piotrowski, M. (2001). Enzymatic characterization of the recombinant Arabidopsis thaliana nitrilase subfamily encoded by the NIT2/NITl/NlT3-gene cluster. Planta, 212,508-516. 

Schreiner U, SteinkeUner G, RozzeU JD, Glieder A, Winkler M. Improved fitness of Arabidopsis thaliana nitrilase 2 [J]. ChemCatChem 2010, 2 (3) 263-267. 

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