<i>Brassica napus</i> soluble epoxide hydrolase (BNSEH1)

Bellevik, Stefan; Zhang, Jiaming; Meijer, Johan

doi:10.1046/j.1432-1033.2002.03247.x

Cited by 18 publications

(11 citation statements)

References 35 publications

(51 reference statements)

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“…In addition, a transcript encoding a long chain fatty acid elongation enzyme (ELo2/SUR4) was highly down-regulated at 5, 10 and 20 dpa. A transcript encoding epoxide hydrolase involved in cutin layer biosynthesis was highly down-regulated at 10 dpa [47]. …”

Section: Resultsmentioning

confidence: 99%

Functional genomics of fuzzless-lintless mutant of Gossypium hirsutum L. cv. MCU5 reveal key genes and pathways involved in cotton fibre initiation and elongation

et al. 2012

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BackgroundFuzzless-lintless cotton mutants are considered to be the ideal material to understand the molecular mechanisms involved in fibre cell development. Although there are few reports on transcriptome and proteome analyses in cotton at fibre initiation and elongation stages, there is no comprehensive comparative transcriptome analysis of fibre-bearing and fuzzless-lintless cotton ovules covering fibre initiation to secondary cell wall (SCW) synthesis stages. In the present study, a comparative transcriptome analysis was carried out using G. hirsutum L. cv. MCU5 wild-type (WT) and it’s near isogenic fuzzless-lintless (fl) mutant at fibre initiation (0 dpa/days post anthesis), elongation (5, 10 and 15 dpa) and SCW synthesis (20 dpa) stages.ResultsScanning electron microscopy study revealed the delay in the initiation of fibre cells and lack of any further development after 2 dpa in the fl mutant. Transcriptome analysis showed major down regulation of transcripts (90%) at fibre initiation and early elongation (5 dpa) stages in the fl mutant. Majority of the down regulated transcripts at fibre initiation stage in the fl mutant represent calcium and phytohormone mediated signal transduction pathways, biosynthesis of auxin and ethylene and stress responsive transcription factors (TFs). Further, transcripts involved in carbohydrate and lipid metabolisms, mitochondrial electron transport system (mETS) and cell wall loosening and elongation were highly down-regulated at fibre elongation stage (5–15 dpa) in the fl mutant. In addition, cellulose synthases and sucrose synthase C were down-regulated at SCW biosynthesis stage (15–20 dpa). Interestingly, some of the transcripts (~50%) involved in phytohormone signalling and stress responsive transcription factors that were up-regulated at fibre initiation stage in the WT were found to be up-regulated at much later stage (15 dpa) in fl mutant.ConclusionsComparative transcriptome analysis of WT and its near isogenic fl mutant revealed key genes and pathways involved at various stages of fibre development. Our data implicated the significant role of mitochondria mediated energy metabolism during fibre elongation process. The delayed expression of genes involved in phytohormone signalling and stress responsive TFs in the fl mutant suggests the need for a coordinated expression of regulatory mechanisms in fibre cell initiation and differentiation.

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Section: Resultsmentioning

confidence: 99%

Functional genomics of fuzzless-lintless mutant of Gossypium hirsutum L. cv. MCU5 reveal key genes and pathways involved in cotton fibre initiation and elongation

et al. 2012

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“…Both the mammalian and the plant soluble epoxide hydrolases, which also belong to phylogenetic group 8, have the same characteristic (11,19,30). Thus, this particular cis versus trans specificity is clearly linked to phylogenetic group 8.…”

Section: Vol 72 2006 Novel Epoxide Hydrolases From Genomic Databasementioning

confidence: 95%

Diversity and Biocatalytic Potential of Epoxide Hydrolases Identified by Genome Analysis

Loo

Kingma

Arand

et al. 2006

Appl Environ Microbiol

108

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Epoxide hydrolases play an important role in the biodegradation of organic compounds and are potentially useful in enantioselective biocatalysis. An analysis of various genomic databases revealed that about 20% of sequenced organisms contain one or more putative epoxide hydrolase genes. They were found in all domains of life, and many fungi and actinobacteria contain several putative epoxide hydrolase-encoding genes. Multiple sequence alignments of epoxide hydrolases with other known and putative ␣/␤-hydrolase fold enzymes that possess a nucleophilic aspartate revealed that these enzymes can be classified into eight phylogenetic groups that all contain putative epoxide hydrolases. To determine their catalytic activities, 10 putative bacterial epoxide hydrolase genes and 2 known bacterial epoxide hydrolase genes were cloned and overexpressed in Escherichia coli. The production of active enzyme was strongly improved by fusion to the maltose binding protein (MalE), which prevented inclusion body formation and facilitated protein purification. Eight of the 12 fusion proteins were active toward one or more of the 21 epoxides that were tested, and they converted both terminal and nonterminal epoxides. Four of the new epoxide hydrolases showed an uncommon enantiopreference for meso-epoxides and/or terminal aromatic epoxides, which made them suitable for the production of enantiopure (S,S)-diols and (R)-epoxides. The results show that the expression of epoxide hydrolase genes that are detected by analyses of genomic databases is a useful strategy for obtaining new biocatalysts.Enantiopure epoxides and vicinal diols are valuable intermediates in the synthesis of a number of pharmaceutical compounds. Epoxide hydrolases (EC 3.3.2.3) catalyze the conversion of epoxides to the corresponding diols. If they are enantioselective, they can be used to produce enantiopure epoxides by means of kinetic resolution (5). In the past, when only epoxide hydrolases from mammalian sources were known (12), the use of epoxide hydrolases in biocatalysis was hampered by their poor availability and insufficient catalytic performance, such as a low turnover rate or poor enantioselectivity. The potential for biocatalytic application of epoxide hydrolases was significantly increased with the discovery of microbial epoxide hydrolases (41), which are easier to produce in large quantities. The cloning and overexpression of several enantioselective epoxide hydrolases, e.g., from Agrobacterium radiobacter (35), Aspergillus niger (3), and potato plants (40), not only facilitated large-scale production of these enzymes but also made it possible to improve their biocatalytic properties by site-directed or random mutagenesis (34,36,43).Since many microbial genome sequences are available in the public domain, it is useful to screen these databases for genes that might encode new enzymes with interesting properties.Novel epoxide hydrolases can be identified by performing a BLAST search of the genomic databases, using amino acid sequences of known epoxide hyd...

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“…In plants, epoxide hydrolase activities have been detected in e.g. mouse ear cress, spinach, soya bean, rape, tobacco and potato [1][2][3][4][5][6][7][8]. A suggested physiological role of the plant enzymes is through their involvement in the epoxide fatty acid metabolism and biosynthetic pathway of cutin [9].…”

Section: Introductionmentioning

confidence: 99%

Catalysis of potato epoxide hydrolase, StEH1

Elfström

Widersten

2005

Biochemical Journal

134

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The kinetic mechanism of epoxide hydrolase (EC 3.3.2.3) from potato, StEH1 (Solanum tuberosum epoxide hydrolase 1), was studied by presteady-state and steady-state kinetics as well as by pH dependence of activity. The specific activities towards the different enantiomers of TSO (trans-stilbene oxide) as substrate were 43 and 3 µmol · min −1 · mg −1 with the R,R-or S,S-isomers respectively. The enzyme was, however, enantioselective in favour of the S,S enantiomer due to a lower K m value. The pH dependences of k cat with R,R or S,S-TSO were also distinct and supposedly reflecting the pH dependences of the individual kinetic rates during substrate conversion. The rate-limiting step for TSO and cis-and trans-epoxystearate was shown by rapid kinetic measurements to be the hydrolysis of the alkylenzyme intermediate. Functional characterization of point mutants verified residues Asp 105 , Tyr 154 , Tyr 235 and His 300 as crucial for catalytic activity. All mutants displayed drastically decreased enzymatic activities during steady state. Presteady-state measurements revealed the base-deficient H300N (His 300 → Asn) mutant to possess greatly reduced efficiencies in catalysis of both chemical steps (alkylation and hydrolysis).

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Brassica napus soluble epoxide hydrolase (BNSEH1)

Cited by 18 publications

References 35 publications

Functional genomics of fuzzless-lintless mutant of Gossypium hirsutum L. cv. MCU5 reveal key genes and pathways involved in cotton fibre initiation and elongation

Functional genomics of fuzzless-lintless mutant of Gossypium hirsutum L. cv. MCU5 reveal key genes and pathways involved in cotton fibre initiation and elongation

Diversity and Biocatalytic Potential of Epoxide Hydrolases Identified by Genome Analysis

Catalysis of potato epoxide hydrolase, StEH1

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