Surface-Binding Peptide Facilitates Electricity-Driven NADPH-Free Cytochrome P450 Catalysis

Article abstract of DOI:10.1002/cctc.201701810

Industrial biotechnology aims to exploit cytochrome P450 enzymes to access their sophisticated catalytic activity for challenging chemical reactions on inert C?H bonds. Limited by the need for NADPH, approaches to bind P450 enzymes to electrode surfaces for an artificial electron supply are promising. Here, we demonstrate that a recombinant fusion of an indium tin oxide binding peptide and the multi-domain class VIII cytochrome P450 BM3 can be used in electrically driven catalysis. Bioelectrocatalytic activity is analyzed by direct product quantification resulting in superior activity of the specifically immobilized P450 BM3 in contrast to unspecifically adsorbed enzyme. Spacer and anchor point studies imply that enzyme flexibility and alignment are crucial factors to achieve high activity on the electrode. Furthermore, we demonstrate that our approach is also feasible for pharmaceutical application using naringenin as substrate.

Full text of DOI:10.1002/cctc.201701810

Accepted Article
Title: Surface-Binding Peptide Facilitates Electricity-Driven NADPH-
Free Cytochrome P450 Catalysis
Authors: Sarah Zernia, Ronny Frank, Renato Weiße, Heinz-Georg
Jahnke, Kathrin Bellmann-Sickert, Andrea Prager, Bernd
Abel, Norbert Sträter, Andrea Robitzki, and Annette G. Beck-
Sickinger
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10.1002/cctc.201701810
ChemCatChem
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Surface-Binding Peptide Facilitates Electricity-Driven NADPH-
Free Cytochrome P450 Catalysis
Sarah Zernia[a], Ronny Frank[b], Dr. Renato H.-J. Weiße[b], Dr. Heinz-Georg Jahnke[b], Dr. Kathrin
Bellmann-Sickert[a], Andrea Prager[c], Prof. Dr. Bernd Abel[c], Prof. Dr. Norbert Sträter[b], Prof. Dr.
Andrea Robitzki[b], Prof. Dr. Annette G. Beck-Sickinger*[a]
Dedicated to Professor Günther Jung on the occasion of his 80th birthday
Abstract: Industrial biotechnology aims to exploit cytochrome P450
enzymes in order to access their sophisticated catalysis for
challenging chemical reactions on inert C-H bonds. Being limited by
the need for NADPH, approaches to bind P450 enzymes to
electrode surfaces for an artificial electron supply are promising.
Here, we demonstrate that a recombinant fusion of an indium tin
oxide binding peptide and the multi-domain class VIII cytochrome
P450 BM3 can be used in electrically driven catalysis.
Bioelectrocatalytic activity is analyzed by direct product
quantification resulting in superior activity of the specifically
immobilized P450 BM3 in contrast to unspecifically adsorbed
enzyme. Spacer and anchor point studies imply that enzyme
flexibility and alignment are crucial factors to achieve high activity on
the electrode. Furthermore, we demonstrate that our approach is
also feasible for pharmaceutical application using naringenin as
substrate.
resembles a eukaryotic-CYP-like structure[10] of a catalytically
active heme-dependent monooxygenase fused to an NADPH-
dependent CYP reductase coordinating FAD and FMN[11,12]
(Figure 1a). Extensive mutational studies of cytochrome P450
BM3 were already carried out to allow oxidation of a broad range
of fine chemical precursors, pharmaceuticals and aromatic
compounds[13] demonstrating the possible areas of application.
To overcome the limiting cofactor NADPH[14]
,
several
approaches addressed alternatives including enzymatic[15–17] and
non-enzymatic[18] regeneration of NADPH or bypassing of
NADPH by photochemical[19,20] and electrochemical[21,22]
methods. Energy supply by direct electron transfer (DET) is
regarded as very progressive method because of its reduced
necessary components[23] and has been achieved for several
enzymes[24–26]
.
For cytochrome P450 BM3 we recently
demonstrated low activity with DET after unspecific adsorption
on indium tin oxide (ITO)[27]. However, directed immobilization of
enzymes on electrodes is thought to enhance enzyme activity
for this approach and provides the advantages of increased
Introduction
storage stability[28] and an easy product/enzyme separation[29,30]
.
Cytochrome P450 enzymes are known for their predominant role
in drug metabolism[1]. They catalyze stereo-specific
hydroxylation on non-activated carbon-hydrogen bonds[2],
dealkylations[3] or epoxidations[4] by the incorporation of oxygen
under mild conditions[5]. Given this wide variety on reactions and
the high-valent iron species[6] as catalytic entity, cytochrome
P450 enzymes (CYP) are promising tools for pharmaceutical
and chemical industry and are already used, for example, in
bioreactors for the production of fatty acid[7] or steroid
derivatives[8]. The microbial cytochrome P450 BM3 is a soluble,
fatty acid hydroxylase and is noted for its high activity[9]. It
[a]
Sarah Zernia, Dr. Kathrin Bellmann-Sickert, Prof. Dr. Annette G.
Beck-Sickinger
Institute of Biochemistry, Leipzig University
Brüderstraße 34, 04103 Leipzig, Germany
E-mail: abeck-sickinger@uni-leipzig.de
[b]
[c]
Ronny Frank, Dr. Heinz-Georg Jahnke, Dr. Renato H.-J. Weiße,
Prof. Dr. Norbert Sträter, Prof. Dr. Andrea Robitzki
Center for Biotechnology and Biomedicine, Leipzig University
Deutscher Platz 5, 04103 Leipzig, Germany
Figure 1. Structural insights into cytochrome P450 BM3. (a) Full-length model.
N-terminally cytochrome P450 monooxygenase (blue); cytochrome P450
reductase: FMN binding (yellow) and FAD/NADPH binding domain (green).
Cofactors are shown as red sticks. Exchanged loop is shown in black, * = C-
terminus. The depicted domain arrangement is artificial and for illustration only.
(b) Flavin cofactor binding pocket of noHSP. C-terminal amino acids in red;
nicotinamide moiety of NADP is not modelled (PDB entry 4dql). Its
approximate position is marked with an asterisk. (c) Model of the elongated C-
terminus of HSP.
Andrea Prager, Prof. Dr. Bernd Abel
Leibniz Institute of Surface Modification (IOM)
Permoserstraße 15, 04318 Leipzig, Germany
Supporting information for this article is given via a link at the end of
the document.
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Recently, we presented an immobilization strategy for
cytochrome P450 BM3 mediated by an ITO binding peptide
(HighSP)[31], which is composed of the sequence (RTRHK)4
enabling strong electrostatic interaction with oxidized metal
surfaces[32]. Incorporated into the target enzyme, this rational
design offers tailoring of enzyme orientation for easy one-step
ELISA studies on C-terminally HA-tagged and N-terminally
FLAG-tagged noHSP (HA-CT noHSP) and HSP (HA-CT HSP)
support the hypothesis of different orientations as HA antibody
recognition on the surface is disturbed only in the case of HSP
demonstrated by significantly reduced maximum response (Emax
)
of 57.5 % (Figure 3a+b). When performing ELISA against the
immobilization without interlayer of silanes or organophosphates. FLAG tag an Emax increase is detected for HA-CT HSP, which
Here, we demonstrate the benefits of an oriented immobilization
strategy to realize efficient electrocatalysis on cytochrome P450
BM3 by DET for the first time. Using the enzymatic dealkylation
of 7-ethoxycoumarin (Figure 2a) and a mutant of cytochrome
means that the accessibility of the FLAG tag is elevated in the
HSP variant. This suggests preferred binding of HSP at the C-
terminus in contrast to
a random adsorption for noHSP.
Scanning electron microscopy revealed a homogeneous and
cohesive protein layer on the surface (Figure 3c+d), however,
does not provide the resolution of single protein orientation yet.
P450 BM3 (A74G, F87V, L188Q)[33]
, we investigated the
influence of the enzyme flexibility and its anchorage points as
well as the binding peptide composition for electrocatalytic
activity. In a deeper characterization, we explored the impact of
enzyme orientation and behavior on ITO surfaces and examined
the applicability of our system for the pharmaceutically relevant
substrate naringenin[34]
.
Results and Discussion
For initial studies, the unmodified cytochrome P450 BM3
(noHSP) was compared to a C-terminally HighSP-tagged variant
(HSP). Activity assays on the constructs were performed in three
set-ups to analyze the effects of protein orientation. In set-up I, 5
pmol of protein were incubated with NADPH and 7-
ethoxycoumarin (7-EC) in solution resulting in the formation of
quantified amounts of 7-hydroxycoumarin (7-HC). In set-up II,
P450 BM3 variants were adsorptively immobilized on ITO (2.1
pmol of protein) and tested in the presence of NADPH and 7-EC.
In set-up III, immobilized P450 BM3 was supplied with 7-EC and
an electric potential of -0.6 V (vs. Ag/AgCl/1 M KCl).
Interestingly, only specifically immobilized cytochrome P450
BM3 was effectively activated by electrons as exclusively HSP
produced remarkable amounts of 7-HC in set-up III (Figure 2d).
Whereas the unmodified P450 BM3 (noHSP) showed high
activity in set-up I (Figure 2b), comparable to values of Lee et
al.[35], it exhibited very low activity after immobilization (set-up II
and III, Figures 2c and 2d). This is due to random orientation on
the ITO surface (illustrated in Figure 2) leading to only a fraction
of molecules, which can be accessed by substrate or undergo
conformational rearrangements upon reduction by either
NADPH or electrons. The necessity of these rearrangements
were already described for human fibroblast CYP reductase[36]
and can be assumed for P450 BM3[37] even with more
complexity as it functions as dimer[38,39]. In contrast, the HSP
variant featured low activity in solution originating from HighSP
blocking of the NADPH binding site (illustrated in Figure 1c vs.
1b), as hypothesized previously[31]. When HSP is immobilized,
the NADPH pocket is unblocked due to electrostatic ITO-HighSP
interaction. Additionally, the HighSP tag fixates the enzyme in an
orientated manner on the electrode (illustrated in Figure 2), that
electron and substrate entering on opposite enzyme sites is
benefited resulting in a tenfold higher activity in comparison to
noHSP.
Figure 2. 7-Ethoxycoumarin activity assay on specifically vs. unspecifically
immobilized cytochrome P450 BM3. (a) Dealkylation of 7-ethoxycoumarin (7-
EC) to 7-hydroxycoumarin (7-HC) by P450 BM3 mutant (A74G, F87V, L188Q).
(b-d): Activity assay of noHSP and HSP on the production of 7-HC / pmol
enzyme. Exact values see SI. n ≥ 3. Statistical analysis with student’s t-test
resulted in p < 0.0001 indicated by ***. (b) Set-up I: in solution, NADPH added.
(c) Set-up II: immobilized P450 BM3 variants on ITO, NADPH added. (d) Set-
up III: immobilized P450 BM3 variants on ITO, electric potential of -0.6 V
applied.
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For investigations on the optimal enzyme-surface distance,
alpha-helical spacers were introduced between enzyme and
HighSP, which consist of one (Ala-HSP) or two (longAla-HSP)
units of the sequence KAKELAEKLAELKA (Tables 1, S1).
Activity measurements indicated that the spacer enhances the
effects of HSP in set-up I and II (Figure 4a). More flexibility
between enzyme and tag led to a higher probability of blocking
NADPH binding site in solution, but coincidental enabled easier
entrance of NADPH in its binding pocket in set-up II, which can
be explained by larger enzyme-surface distance. However, in
set-up III, the spacer does not affect the activity in comparison to
HSP. Although helical peptides are known to tunnel electrons
and II, which was attributed to a steric distortion of the NADPH
binding pocket by length-divergent loop alteration (Figure 4a)[46]
.
By application of -0.6 V, the distorted NADPH binding is
bypassed leading to equal activity with respect to HSP.
Therefore, the loop region in the reductase domain presents a
second suitable anchor point that supports DET from ITO
electrode to P450 BM3.
The plant pigment naringenin and its hydroxylation product
eriodictyol are interesting targets for pharmaceutical industry, as
they feature beneficial effects in humans[47,48]. A cost-effective
synthesis of naringenin is established in an E.coli whole cell
approach[49], but hydroxylation to eriodictyol, which exhibits
higher water solubility and is therefore more suitable for
application[50], is still a challenge. Here, we apply our P450 BM3
electrode, using the HSP construct, to produce eriodictyol from
naringenin without the need for additional reagents or further
purification.
over large distances[40]
, our results indicate no additional
conductive effects of the spacer, as confirmed by a randomly
coiled poly-glycine spacer (Table S2, Figure S3).
Figure 3. Insights into protein orientation on metal surfaces. (a) anti-HA ELISA
of C-terminally modified variants HA-CT noHSP and HA-CT HSP on ITO.
Concentration-response curves from 10-10 to 10-5.5 M of immobilized enzyme
were measured and normalized to the highest value of HA-CT noHSP of every
single experiment, n = 3. (b) Summary of anti-HA and anti-FLAG ELISA of HA-
CT noHSP and HA-CT HSP. Emax is the maximum response of the binding
curves, n = 3, statistical analysis with student’s t-test revealed in a very
significant difference of Emax in anti-HA ELISA with p < 0.0001 illustrated by
***. (c+d) Scanning electron microscopy of silica wafer edges. (c) HSP
construct immobilized on SiO2 wafer, magnification: 100,000 x. (d) SiO2 wafer,
magnification: 15,280 x.
Figure 4. Activity characteristics of cytochrome P450 BM3 variants on a
fluorescent and
a pharmaceutical substrate. (a) Activity assay on the
production of 7-HC / pmol enzyme of cytochrome P450BM3 constructs in set-
up I, II and III with four different P450 BM3 variants. Exact values see SI. n ≥ 3.
(b) RP-HPLC on pure naringenin (black) and eriodictyol (grey). Gradient: 30 to
70 % ACN/H2O for 40 min. Integral of different eriodictyol concentrations was
used to determine a calibration curve to calculate the enzymatically produced
eriodictyol amount. (c) Activity assay on the production of eriodictyol per pmol
of HSP in set-up I, II and III. n ≥ 3.
Although there have been trials dealing with DET to the
separated heme domain of cytochrome P450 BM3[41], we chose
a full-length enzyme approach to allow translation of the artificial
electron supply into the native and sensitive electron path of the
catalytic heme complex. As available crystal structures[42–44] and
further computational predictions (Figure S3) suggested a less
shielded environment for the flavin cofactors compared to the
buried heme, anchor points for immobilization on electrodes
should be in close vicinity of the FAD cofactor[45]. Hence, we
additionally introduced the HighSP sequence in a loop region
near the FAD pocket exchanging the amino acids 855-859 from
WSGYG to (RTHRK)2. This led to a loss of activity in set-up I
For product quantification, RP-HPLC analyses (Figure 4b) of the
extracted molecules and pure standards were applied. Figure 4c
displays, that most eriodictyol is formed in set-up III keeping the
trend of improved activity after immobilization and showing that
the electrode is suitable for naringenin conversion. The amounts
of product are comparable to the aforementioned amounts of
produced 7-hydroxycoumarin, but far lower than values reported
by Chu et al., who utilized the mutant R47L, L86I, F87V, L188Q
in solution[51]. Additional introduction of the mutations R47L and
L86I into the HSP construct did not result in higher activity (data
not shown) suggesting that in this case not substrate saturation
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but electron coupling and enzyme stability are limiting factors in
bioelectrocatalysis, which should be focused in subsequent
studies. Nevertheless, this is the first step for applying our
peptide-based immobilization technique to the production of an
industrially relevant compound.
variants[41]. While the FAD domain cushions possible structural
distortion by immobilization, the FMN domain can implement the
artificial electron supply into the natural redox chain and the
heme domain is protected from structural stress. With the
conversion of naringenin to eriodictyol we demonstrated a first
reference for the applicability of our electrode for chemical and
pharmaceutical purposes.
A closer look at the P450 BM3 binding characteristics displays
strong protein/ITO interactions even without the HighSP-peptide
(Table 1), which is explicable with a chelating effect with
stochastic orientation. However, all enzyme variants bind with
sub-micromolar affinity and saturate the electrode surface during
the adsorptive immobilization as determined by ELISA. For HSP
and noHSP the equivalence of amount of immobilized protein
was further proven by quartz crystal microbalance (Figure S4).
Kinetic comparison of HSP in set-up I and III showed a similar
time profile and a continuously increasing amount of produced
7-HC (Figure S5a), which demonstrates that HSP stability is not
affected by the electrode potential of -0.6 V in the given period.
Considering the non-covalent binding of FMN and FAD in P450
BM3[52], activity might originate from cofactor diffusion which was
examined by varying the presence of external flavins (Figure S8).
We found no significant difference in either HSP or noHSP, so
we conclude that the bioelectrocatalytic mechanism is
independent of soluble flavins.
Experimental Section
Cloning. Triple mutant of P450 BM3 (A74G, F87V, L188Q) was cloned
with an N-terminal FLAG-Tag (DYKDDDDK) in pRSF1b vector. Insertion
of the C-terminal peptidic linkers and mutation of the loop sequence was
performed using Overlap-Extension-PCR.
Expression and purification. P450 BM3 constructs were expressed in
E.coli BL21(DE3) or E.coli ER2566 (only FLAG-P450BM3-noHSP) as
described elsewhere[29]. After harvesting, cells were resuspended in TBS
buffer (50 mM Tris, 150 mM NaCl, pH 7.4), lysed by FastPrep (MP
Biomedicals, USA) for 30 s at 6 m/s and centrifuged for 30 min at 18,000
g. For purification anti-FLAG M2 Affinity Gel (Sigma-Aldrich, USA) was
used. After loading the supernatant of the lysate on the agarose, the
column was washed with TBS buffer and protein was eluted using 100
µg/ml FLAG-tag peptide (ApexBio, USA) in TBS buffer. The P450 BM3
sample was concentrated using Amicon filters (MWCO 3000, Merck
Millipore, USA) and stored in 20 % glycerol at 4 °C.
Table 1. P450 BM3 constructs with additionally introduced peptides
sequences and resulting binding affinities. For HSP, Loop construct the amino
acids 855-859 were exchanged. All constructs contained mutations A74G,
F87V, L188Q and an N-terminal FLAG tag for purification and antibody
detection. Anti-FLAG ELISA concentration response curves (see SI) with 10-5
Characterization of P450 BM3 variants. The identity of all P450 BM3
variants was verified by CO difference spectrum[47] and mass
spectrometry. Therefore the protein was measured after ZipTip (C4 resin,
Merck Millipore, USA) in MALDI-ToF mass spectrometer (Ultraflex III,
Bruker Daltonics, Germany) using SDHB matrix.
to 10-10 M protein on ITO resulted in EC50 values and logarithmic EC50 (pEC50
)
± SEM, n ≥ 3.
protein
linker sequence
EC50
pEC50 (SEM)
Computational structure analysis. Structures of the respective
domains of P450 BM3 were obtained from the Protein Data Bank (PDB,
https://www.rcsb.org). The CYP domain and the FMN subdomain of the
CYP reductase were extracted from PDB entry 1BVY[48]. Coordinates of
the FAD domain was obtained from PDB entry 4DQL[38]. For figure 1 the
FMN and FAD subdomains were oriented similar to the crystal structure
of human CYPOR (PDB entry 3QE2[49]). The monooxygenase domain
was oriented artificially near the FMN subdomain. Figures were prepared
with PyMOL (The PyMOL Molecular Graphics System, Version 1.7.6
Schrödinger, LLC.). Structural models of the spacer peptides, HighSP
and a spacer-HighSP combination were generated by PEP-FOLD3[50]
noHSP
HSP
-
34 nM
7.47 ± 0.10
6.72 ± 0.08
6.96 ± 0.08
(RTHRK)4
189 nM
110 nM
Ala-HSP
KAKELAEKLAELKA-
(RTHRK)4
longAla-HSP
(KAKELAEKLAELKA)2-
(RTHRK)4
97 nM
7.02 ± 0.06
HSP, Loop
(RTHRK)2
60 nM
7.22 ± 0.05
6.89 ± 0.04
6.37 ± 0.07
running at the Mobyle portal[51] of the RPBS server[52]
.
HA-CT noHSP
HA-CT HSP
YPYDVPDYA
129 nM
427 nM
YPYDVPDYA-(RTHRK)4
ITO surface production in 96-well format. Indium tin oxide electrodes
for ELISA and for activity assays in 96-microtiter plates were produced as
described previously[25]
.
Conclusions
ELISA. P450 BM3 variants were diluted in TBS buffer resulting in
concentrations ranging from 10-10 to 10-5 M and then incubated on 96-well
plates covered with indium tin oxide (ITO) for 1 h at 4 °C (55 µM / well).
Then ELISA was performed as described elsewhere[30]. Antibodies:
1:5000 anti-FLAG-HRP (abcam, United Kingdom) in 1 % BSA/TBS;
1:2500 anti-HA-POD (Roche, Switzerland) in 1 % BSA/TBS. 100 µl/well
were applied for all solutions. Surfaces incubated with TBS buffer served
as negative control. The data was analyzed with GraphPad Prism 5
software (GraphPad software, USA) resulting in EC50 values calculated
as mean of at least three independent experiments. Logarithmic EC50
(pEC50) were utilized to enable calculation of standard error of mean
In summary, our study demonstrates that specific immobilization
on ITO through binding peptides is a powerful strategy to reach
the goals of bioelectrocatalysis with short distances, a proper
enzyme orientation and good substrate accessibility[23]. The use
of recombinant enzymes allows variable peptide insertion for
tailoring of functionality. Electrocatalytic activity was observed
despite the different types of anchor points emphasizing the
robustness of a full-length approach in contrast to truncated
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(SEM). For anti-FLAG ELISA of noHSP, HSP, Ala-HSP, longAla-HSP
and HSP, Loop the highest value of every individual experiment of every
construct was set 100 %. For ELISA of HA-CT noHSP and HA-CT HSP
both construct were always measured in parallel and the highest value of
HA-CT noHSP in every single experiment was set 100 % to get the ratio
between HA-CT noHSP and HA-CT HSP. Emax was calculated as the
difference between lowest and highest value of the mean binding curve.
Calculation of amount of enzyme on electrode surface. To compare
set-up I with II and III, the amount of immobilized enzyme was assessed
by a theoretical calculation joined by AFM data[25] for a monolayer in
square packaging. P450 BM3 molecule was estimated to have a cross-
section of 50 nm2. This resulted in a protein amount of 2.1 pmol per well.
Acknowledgements
Scanning electron microscopy. 1 µM of HSP enzyme was immobilized
on silica wafer (25 mm2) for 1 h at 4 °C without shaking. Surfaces were
washed with TBS and afterward with pure water to remove salts and
dried with nitrogen. Scanning electron microscopy (ULTRA 55, Carl Zeiss
SMT, Oberkochen) was performed using an Inlens detector at an
acceleration voltage of 2 kV.
This project was funded by the Federal Ministry of Education
and Research of Germany (project 031A181A). We thank
Regina Reppich-Sacher for technical assistance in mass
spectrometry and the c-LEcta GmbH, Leipzig for providing the
P450 BM3 plasmid.
7-ethoxycoumarin activity assay. Enzyme activity was fluorometrically
quantified by conversion of the substrate 7-ethoxycoumarine (Alfa Aesar,
USA) to the detected product 7-hydroxycoumarine as described
recently[25]. Pure 7-hydroxycoumarin (Sigma Aldrich, USA) was used in
controls. For mechanistic studies activity was measured in three different
situations: set-up I: enzyme in solution (5 pmol) and in presence of
NADPH (AppliChem, Germany); or enzyme adsorptively immobilized on
indium tin oxide surfaces (geometric area = 44 mm2) in presence of
NADPH (set-up II) or under electrode potential control (standard -0.6 V
vs Ag/AgCl/1 M KCl) (set-up III), unless stated otherwise. NADPH was
regenerated during reaction by addition of glucose dehydrogenase (1 U,
from Pseudomonas sp., Sigma-Aldrich, USA) and glucose (50 mM,
Sigma-Aldrich, USA). Bioelectrocatalytic experiments were conducted in
12 parallel three-electrode two chamber setups applying our new
Keywords: cytochrome P450 BM3 (CYP102A1) •
electrochemistry • immobilization • product quantification •
RTHRK peptide
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Direct electron transfer to P450
BM3: Recombinantly expressed
P450 BM3 was specifically
immobilized through indium tin oxide
binding peptide for direct electron
supply. The resulting high enzymatic
activity was studied in terms of
peptide length, enzyme-peptide
distance, anchor point position and
enzyme-to-surface orientation
Sarah Zernia, Ronny Frank, Dr.
Renato H.-J. Weiße, Dr. Heinz-Georg
Jahnke, Dr. Kathrin Bellmann-Sickert,
Andrea Prager, Prof. Dr. Bernd Abel,
Prof. Dr. Norbert Sträter, Prof. Dr.
Andrea Robitzki, Prof. Dr. Annette G.
Beck-Sickinger*
Page No. – Page No.
Surface-Binding Peptide Facilitates
Electricity-Driven NADPH-Free
Cytochrome P450 Catalysis
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Author(s), Corresponding Author(s)*
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Title
Text for Table of Contents
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