Nitrilases participate in the nitrile metabolism in microbes and plants. They are widely used to produce carboxylic acids from nitriles. Nitrilases were described in bacteria, Ascomycota and plants. However, they remain unexplored in Basidiomycota. Yet more than 200 putative nitrilases are found in this division via GenBank. The majority of them occur in the subdivision Agaricomycotina. In this work, we analyzed their sequences and classified them into phylogenetic clades. Members of clade 1 (61 proteins) and 2 (25 proteins) are similar to plant nitrilases and nitrilases from Ascomycota, respectively, with sequence identities of around 50%. The searches also identified five putative cyanide hydratases (CynHs). Representatives of clade 1 and 2 (NitTv1 from Trametes versicolor and NitAg from Armillaria gallica, respectively) and a putative CynH (NitSh from Stereum hirsutum) were overproduced in Escherichia coli. The substrates of NitTv1 were fumaronitrile, 3-phenylpropionitrile, β-cyano-l-alanine and 4-cyanopyridine, and those of NitSh were hydrogen cyanide (HCN), 2-cyanopyridine, fumaronitrile and benzonitrile. NitAg only exhibited activities for HCN and fumaronitrile. The substrate specificities of these nitrilases were largely in accordance with substrate docking in their homology models. The phylogenetic distribution of each type of nitrilase was determined for the first time.
- MeSH
- aminohydrolasy chemie genetika metabolismus MeSH
- Basidiomycota klasifikace enzymologie genetika MeSH
- fumaráty metabolismus MeSH
- fungální proteiny chemie genetika metabolismus MeSH
- fylogeneze MeSH
- kyanovodík metabolismus MeSH
- pyridiny metabolismus MeSH
- simulace molekulového dockingu MeSH
- substrátová specifita MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- Publikační typ
- časopisecké články MeSH
The recently discovered cytokinin (CK)-specific phosphoribohydrolase "Lonely Guy" (LOG) is a key enzyme of CK biosynthesis, converting inactive CK nucleotides into biologically active free bases. We have determined the crystal structures of LOG from Claviceps purpurea (cpLOG) and its complex with the enzymatic product phosphoribose. The structures reveal a dimeric arrangement of Rossmann folds, with the ligands bound to large pockets at the interface between cpLOG monomers. Structural comparisons highlight the homology of cpLOG to putative lysine decarboxylases. Extended sequence analysis enabled identification of a distinguishing LOG sequence signature. Taken together, our data suggest phosphoribohydrolase activity for several proteins of unknown function.
- MeSH
- aminohydrolasy chemie metabolismus MeSH
- Claviceps enzymologie MeSH
- cytokininy metabolismus MeSH
- fungální proteiny chemie metabolismus MeSH
- karboxylyasy chemie metabolismus MeSH
- molekulární modely * MeSH
- sekvence aminokyselin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The application of arylacetonitrilases from filamentous fungi to the hydrolysis of high concentrations of (R,S)-mandelonitrile (100-500 mM) was demonstrated for the first time. Escherichia coli strains expressing the corresponding genes were used as whole-cell catalysts. Nitrilases from Aspergillus niger, Neurospora crassa, Nectria haematococca, and Arthroderma benhamiae (enzymes NitAn, NitNc, NitNh, and NitAb, respectively) exhibited different degrees of enantio- and chemoselectivity (amide formation). Their enantio- and chemoselectivity was increased by increasing pH (from 8 to 9-10) and adding 4-10% (v/v) toluene as the cosolvent. NitAn and NitNc were able to convert an up to 500 mM substrate in batch mode. NitAn formed a very low amount of the by-product, amide (<1% of the total product). This enzyme produced up to >70 g/L of (R)-mandelic acid (e.e. 94.5-95.6%) in batch or fed-batch mode. Its volumetric productivities were the highest in batch mode [571 ± 32 g/(L d)] and its catalyst productivities in fed-batch mode (39.9 ± 2.5 g/g of dcw). NitAb hydrolyzed both enantiomers of 100 mM (R,S)-mandelonitrile at pH 5.0 and is therefore promising for the enantioretentive transformation of (S)-mandelonitrile. Sequence analysis suggested that fungal arylacetonitrilases with similar properties (enantioselectivity, chemoselectivity) were clustered together.
- MeSH
- aminohydrolasy chemie genetika metabolismus MeSH
- Arthrodermataceae enzymologie MeSH
- Aspergillus niger enzymologie MeSH
- druhová specificita MeSH
- fungální proteiny chemie genetika metabolismus MeSH
- fylogeneze MeSH
- koncentrace vodíkových iontů MeSH
- kyseliny mandlové metabolismus MeSH
- Nectria enzymologie MeSH
- Neurospora crassa enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Escherichia coli strains expressing different nitrilases transformed nitriles or KCN. Six nitrilases (from Aspergillus niger (2), A. oryzae, Neurospora crassa, Arthroderma benhamiae, and Nectria haematococca) were arylacetonitrilases, two enzymes (from A. niger and Penicillium chrysogenum) were cyanide hydratases and the others (from P. chrysogenum, P. marneffei, Gibberella moniliformis, Meyerozyma guilliermondi, Rhodococcus rhodochrous, and R. ruber) preferred (hetero)aromatic nitriles as substrates. Promising nitrilases for the transformation of industrially important substrates were found: the nitrilase from R. ruber for 3-cyanopyridine, 4-cyanopyridine and bromoxynil, the nitrilases from N. crassa and A. niger for (R,S)-mandelonitrile, and the cyanide hydratase from A. niger for KCN and 2-cyanopyridine.
- MeSH
- aminohydrolasy chemie genetika metabolismus MeSH
- dehydratasy chemie genetika metabolismus MeSH
- Escherichia coli genetika MeSH
- fungální proteiny chemie genetika metabolismus MeSH
- genom fungální * MeSH
- genomika MeSH
- houby enzymologie genetika MeSH
- rekombinantní proteiny chemie genetika metabolismus MeSH
- sekvenční analýza DNA MeSH
- sekvenční homologie aminokyselin MeSH
- sekvenční seřazení MeSH
- substrátová specifita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Nitrilases are highly conserved proteins with catabolic activity but much less understood functions in cell division and apoptosis. To elucidate the biological functions of Arabidopsis NITRILASE1, we characterized its molecular forms, cellular localization and involvement in cell proliferation and plant development. We performed biochemical and mass spectrometry analyses of NITRILASE1 complexes, electron microscopy of nitrilase polymers, imaging of developmental and cellular distribution, silencing and overexpression of nitrilases to study their functions. We found that NITRILASE1 has an intrinsic ability to form filaments. GFP-NITRILASE1 was abundant in proliferating cells, distributed in cytoplasm, in the perinuclear area and associated with microtubules. As cells exited proliferation and entered differentiation, GFP-NITRILASE1 became predominantly nuclear. Nitrilase silencing dose-dependently compromised plant growth, led to loss of tissue organization and sustained proliferation. Cytokinesis was frequently aborted, leading to enlarged polyploid cells. In reverse, independently transformed cell lines overexpressing GFP-NITRILASE1 showed slow growth and increased rate of programmed cell death. Altogether, our data suggest that NITRILASE1 homologues regulate the exit from cell cycle and entry into differentiation and simultaneously are required for cytokinesis. These functions are essential to maintain normal ploidy, genome stability and tissue organization.
- MeSH
- aminohydrolasy chemie genetika metabolismus ultrastruktura MeSH
- Arabidopsis cytologie genetika růst a vývoj MeSH
- buněčná diferenciace genetika MeSH
- buněčná smrt genetika MeSH
- buněčný cyklus genetika MeSH
- cytoplazma metabolismus MeSH
- cytoskelet genetika metabolismus MeSH
- hydrolasy působící na anhydridy kyselin genetika MeSH
- nádorové proteiny genetika MeSH
- nestabilita genomu * MeSH
- proliferace buněk MeSH
- regulace genové exprese u rostlin MeSH
- RNA interference MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nitrilases from Aspergillus niger CBS 513.88, A. niger K10, Gibberella moniliformis, Neurospora crassa OR74A, and Penicillium marneffei ATCC 18224 were expressed in Escherichia coli BL21-Gold (DE3) after IPTG induction. N. crassa nitrilase exhibited the highest yield of 69,000 U L(-1) culture. Co-expression of chaperones (GroEL/ES in G. moniliformis and P. marneffei; GroEL/ES and trigger factor in N. crassa and A. niger CBS 513.88) enhanced the enzyme solubility. Specific activities of strains expressing the former two enzymes increased approximately fourfold upon co-expression of GroEL/ES. The enzyme from G. moniliformis (co-purified with GroEL) preferred benzonitrile as substrate (K(m) of 0.41 mM, V(max) of 9.7 μmol min(-1) mg(-1) protein). The P. marneffei enzyme (unstable in its purified state) exhibited the highest V(max) of 7.3 μmol min(-1) mg(-1) protein in cell-free extract, but also a high K(m) of 15.4 mM, for 4-cyanopyridine. The purified nitrilases from A. niger CBS 513.88 and N. crassa acted preferentially on phenylacetonitrile (K(m) of 3.4 and 2.0 mM, respectively; V(max) of 10.6 and 17.5 μmol min(-1) mg(-1) protein, respectively), and hydrolyzed also (R,S)-mandelonitrile with higher K(m) values. Significant amounts of amides were only formed by the G. moniliformis nitrilase from phenylacetonitrile and 4-cyanopyridine.
- MeSH
- aminohydrolasy chemie genetika izolace a purifikace metabolismus MeSH
- Escherichia coli genetika MeSH
- exprese genu MeSH
- fungální proteiny chemie genetika izolace a purifikace metabolismus MeSH
- houby enzymologie genetika MeSH
- kinetika MeSH
- klonování DNA MeSH
- koncentrace vodíkových iontů MeSH
- molekulární chaperony genetika metabolismus MeSH
- rekombinantní proteiny chemie genetika izolace a purifikace metabolismus MeSH
- stabilita enzymů MeSH
- substrátová specifita MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Adenine and adenosine-acting aminohydrolases are important groups of enzymes responsible for the metabolic salvage of purine compounds. Several subclasses of these enzymes have been described and given current knowledge of the full genome sequences of many organisms, it is possible to identify genes encoding these enzymes and group them according to their primary structure. METHODS AND RESULTS: This article is a short overview of the enzymes classified as adenine and adenosine deaminase. It summarises knowledge of their occurrence, genetic basis and their catalytic and structural properties. CONCLUSIONS: These enzymes are constitutive components of purine metabolism and their impairment may cause serious medical disorders. In humans, adenosine deaminase deficiency is linked to severe combined immunodeficiency and as such the enzyme has been approved for the first gene therapy trial. The role of these enzymes in plants is unclear, since the activity was has not been detected in extracts and putative genes have not been yet cloned and analyzed. A literature search and amino acid identity comparison show that Ascomycetes contain only adenine deaminase, but not adenosine deaminase, despite the fact that corresponding genes are annotated in databases as the adenosine cleaving enzymes because they share the same conserved domain.
- MeSH
- adenosindeaminasa chemie genetika MeSH
- aminohydrolasy chemie genetika MeSH
- aminokyseliny analýza MeSH
- Bacteria enzymologie MeSH
- lidé MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
