Laser Photoexcitation of NAD(P)H Induces Reduction of P450 BM3 Heme Domain on the Microsecond Time Scale

2007 ◽  
Vol 129 (20) ◽  
pp. 6647-6653 ◽  
Author(s):  
Hazel M. Girvan ◽  
Derren J. Heyes ◽  
Nigel S. Scrutton ◽  
Andrew W. Munro
Keyword(s):  
Time Scale ◽  
P450 Bm3 ◽  
Heme Domain

scholarly journals Reduction of Dioxygen Catalyzed by Pyrene-Wired Heme Domain Cytochrome P450 BM3 Electrodes

2004 ◽  
Vol 126 (33) ◽  
pp. 10218-10219 ◽  
Author(s):  
Andrew K. Udit ◽  
Michael G. Hill ◽  
V. Garrett Bittner ◽  
Frances H. Arnold ◽  
Harry B. Gray
Keyword(s):  
Cytochrome P450 ◽  
P450 Bm3 ◽  
Heme Domain ◽  
Cytochrome P450 Bm3

scholarly journals Promoting P450 BM3 heme domain dimerization with a tris(5‐iodoacetamido‐1,10‐phenanthroline)Ru(II) complex

2020 ◽  
Vol 67 (4) ◽  
pp. 536-540 ◽  
Author(s):  
Mallory Kato ◽  
Bridget Foley ◽  
Julia Vu ◽  
Michael Huynh ◽  
Kathreena Lucero ◽  
...  
Keyword(s):  
P450 Bm3 ◽  
Heme Domain

Cobaltocene-mediated catalytic monooxygenation using holo and heme domain cytochrome P450 BM3

2004 ◽  
Vol 98 (9) ◽  
pp. 1547-1550 ◽  
Author(s):  
Andrew K. Udit ◽  
Frances H. Arnold ◽  
Harry B. Gray
Keyword(s):  
Cytochrome P450 ◽  
P450 Bm3 ◽  
Heme Domain ◽  
Cytochrome P450 Bm3

Insights on intermolecular FMN-heme domain interaction and the role of linker length in cytochrome P450cin fusion proteins

2020 ◽  
Vol 401 (11) ◽  
pp. 1249-1255
Author(s):  
Ketaki D. Belsare ◽  
Anna Joëlle Ruff ◽  
Ronny Martinez ◽  
Ulrich Schwaneberg
Keyword(s):  
Fusion Protein ◽  
Enzyme System ◽  
Cytochrome P450s ◽  
Similar Amount ◽  
Domain Interaction ◽  
P450 Bm3 ◽  
Linker Length ◽  
Heme Domain

AbstractCytochrome P450s are an important group of enzymes catalyzing hydroxylation, and epoxidations reactions. In this work we describe the characterization of the CinA–CinC fusion enzyme system of a previously reported P450 using genetically fused heme (CinA) and FMN (CinC) enzyme domains from Citrobacter braaki. We observed that mixing individually inactivated heme (-) with FMN (-) domain in the CinA-10aa linker - CinC fusion constructs results in recovered activity and the formation of (2S)-2β-hydroxy,1,8-cineole (174 µM), a similar amount when compared to the fully functional fusion protein (176 µM). We also studied the effect of the fusion linker length in the activity complementation assay. Our results suggests an intermolecular interaction between heme and FMN parts from different CinA–CinC fusion protein similar to proposed mechanisms for P450 BM3 on the other hand, linker length plays a crucial influence on the activity of the fusion constructs. However, complementation assays show that inactive constructs with shorter linker lengths have functional subunits, and that the lack of activity might be due to incorrect interaction between fused enzymes.

scholarly journals Structural insights of mediated electron transfer by P450 BM3 monooxygenase

2014 ◽  
Vol 70 (a1) ◽  
pp. C1169-C1169
Author(s):  
Saravanan Panneerselvam ◽  
Aamir Shehzad ◽  
Jochen Mueller-Dieckmann ◽  
Ulrich Schwaneberg
Keyword(s):  
Electron Transfer ◽  
Active Site ◽  
Water Soluble ◽  
Electron Sources ◽  
P450 Bm3 ◽  
Redox Partner ◽  
Access Channel ◽  
Mediated Electron Transfer ◽  
Heme Domain ◽  
Drug Synthesis

P450 BM3 is a 119-kDa water-soluble heme monooxygenase originating from Bacillus megaterium. P450 BM3 and variants are known to oxidize structurally diverse substrates. However, the requirement for the natural cofactor, NADPH, limits cell-free applications of P450 BM3 in drug synthesis, fuelling efforts to establish alternative cofactor system. Hence, P450 BM3 variants have been generated which circumvent the requirement for NADPH, and enabled P450 BM3 to be driven with alternative electron sources. In this study, crystal structures of the P450 BM3 M7 heme domain variant (F87A, V281G, M354S) with and without cobalt (III) sepulchrate are reported. Cobalt (III) sepulchrate acts as an electron shuttle in an alternative cofactor system employing zinc dust as the electron source. The crystal structure shows a binding site for the mediator cobalt (III) sepulchrate at the entrance of the substrate access channel. The mediator occupies a position which is far from the active site and distinct from the binding of the natural redox partner (FAD/NADPH binding domain). The unusual binding position suggests that the mediator shuttles electrons to the heme-centre through new routes. Electron transfer could occur by a `through-protein' or a `substrate-relayed' pathway. The latter seems more plausible since it would ensure efficient use of electrons only in the presence of a substrate in the active site. The structural evidence also indicates that the use of a positively charged mediator is important to effectively reduce the catalytic heme domain. Understanding the mediator-monooxygenase interface opens new avenues for tailoring P450 BM3 to match application demands. Structural and molecular understanding of mediated electron transfer enables a paradigm shift from a mediator acceptance screening to a rational mediator design which considers only stability and electron transfer performance parameters.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

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