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501.
Andrew W. Munro Hazel M. GirvanKirsty J. McLean 《Biochimica et Biophysica Acta (BBA)/General Subjects》2007
The cytochromes P450 (P450s) are a broad class of heme b-containing mono-oxygenase enzymes. The vast majority of P450s catalyse reductive scission of molecular oxygen using electrons usually derived from coenzymes (NADH and NADPH) and delivered from redox partner proteins. Evolutionary advantages may be gained by fusion of one or more redox partners to the P450 enzyme in terms of e.g. catalytic efficiency. This route was taken by the well characterized flavocytochrome P450BM3 system (CYP102A1) from Bacillus megaterium, in which soluble P450 and cytochrome P450 reductase enzymes are covalently linked to produce a highly efficient electron transport system for oxygenation of fatty acids and related molecules. However, genome analysis and ongoing enzyme characterization has revealed that there are a number of other novel classes of P450–redox partner fusion enzymes distributed widely in prokaryotes and eukaryotes. This review examines our current state of knowledge of the diversity of these fusion proteins and explores their structural composition and evolutionary origins. 相似文献
502.
J D Haddock D A Pelletier D T Gibson 《Journal of industrial microbiology & biotechnology》1997,19(5-6):355-359
The ferredoxin component (ferredoxinBPH) of biphenyl 2,3-dioxygenase was purified to homogeneity from crude cell extract of Pseudomonas sp strain LB400 using ion exchange, hydrophobic interaction and gel filtration column chromatography. The protein was a
monomer with a molecular weight of 15000 and contained 2 gram-atoms each of iron and acid-labile sulfur. Ultraviolet-visible
absorbance spectroscopy showed peaks at 325 nm and 460 nm with a broad shoulder around 575 nm. The spectrum was partially
bleached in the visible region upon reduction by reductaseBPH with NADPH as the source of electrons. Electron paramagnetic resonance spectrometry showed no signals for the oxidized
protein. Upon reduction with sodium dithionite, signals with gx = 1.82, gy = 1.92 and gz = 2.02 were detected. These results indicate that the protein contains a Rieske-type (2Fe-2S) iron-sulfur center. FerredoxinBPH was required for the oxidation of biphenyl by the terminal oxygenase component of the enzyme and is probably involved in
the transfer of reducing equivalents from reductaseBPH to the terminal oxygenase during catalysis.
Received 01 November 1996/ Accepted in revised form 27 May 1997 相似文献
503.
N Connors R Prevoznak M Chartrain J Reddy R Singhvi Z Patel R Olewinski P Salmon J Wilson R Greasham 《Journal of industrial microbiology & biotechnology》1997,18(6):353-359
Two mutation and selection methods were used to isolate mutants of Pseudomonas putida F1 which convert indene to cis-(1S),(2R)-indandiol in a toluene-independent fashion. Using soybean or silicone oil as a second phase to deliver indene to the culture,
cis-(1S),(2R)-indandiol, cis-(1R),(2S)-indandiol, 1,2-indenediol (or the keto-hydroxy indan tautomer), and the monooxygenation products 1-indenol and 1-indanone
were produced from indene as a function of time. Similarly the enantiomeric excess of the cis-(1S),(2R)-indandiol produced also increased with increasing time. In addition, mutants were isolated which produced cis-(1S),(2R)-indandiol of lower optical purity which corresponded to reduced levels of 1,2-indenediol. These data suggest this toluene
dioxygenase produces cis-(1S),(2R)-indandiol of low optical purity and that cis-glycol dehydrogenase plays a role in resolving the two cis-1,2-indandiol enantiomers.
Received 15 November 1996/ Accepted in revised form 09 March 1997 相似文献