Protein-Protein Interactions in the P450 Monooxygenase System

1999 ◽  
pp. 21-39
Author(s):  
John B. Schenkman ◽  
Ingela Jansson ◽  
Gary Davis ◽  
Paul P. Tamburini ◽  
Zhongqing Lu ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Monooxygenase System ◽  
Protein Protein Interactions ◽  
P450 Monooxygenase

scholarly journals Detection of Protein-Protein Interactions in the Alkanesulfonate Monooxygenase System from Escherichia coli

2006 ◽  
Vol 188 (23) ◽  
pp. 8153-8159 ◽  
Author(s):  
Kholis Abdurachim ◽  
Holly R. Ellis
Keyword(s):  
Circular Dichroism ◽  
Protein Interactions ◽  
Visible Region ◽  
Circular Dichroism Spectroscopy ◽  
Flavin Mononucleotide ◽  
Stable Complex ◽  
Monooxygenase System ◽  
Protein Protein Interactions ◽  
Alkanesulfonate Monooxygenase ◽  
Circular Dichroïsm

ABSTRACT The two-component alkanesulfonate monooxygenase system utilizes reduced flavin as a substrate to catalyze a unique desulfonation reaction during times of sulfur starvation. The importance of protein-protein interactions in the mechanism of flavin transfer was analyzed in these studies. The results from affinity chromatography and cross-linking experiments support the formation of a stable complex between the flavin mononucleotide (FMN) reductase (SsuE) and monooxygenase (SsuD). Interactions between the two proteins do not lead to overall conformational changes in protein structure, as indicated by the results from circular dichroism spectroscopy in the far-UV region. However, subtle changes in the flavin environment of FMN-bound SsuE that occur in the presence of SsuD were identified by circular dichroism spectroscopy in the visible region. These data are supported by the results from fluorescent spectroscopy experiments, where a dissociation constant of 0.0022 ± 0.0010 μM was obtained for the binding of SsuE to SsuD. Based on these studies, the stoichiometry for protein-protein interactions is proposed to involve a 1:1 monomeric association of SsuE with SsuD.

scholarly journals Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes b5

2015 ◽  
Vol 61 (4) ◽  
pp. 468-474
Author(s):  
O.V. Gnedenko ◽  
A.S. Ivanov ◽  
E.O. Yablokov ◽  
S.A. Usanov ◽  
D.V. Mukha ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Dissociation Constants ◽  
Cytochromes P450 ◽  
Cytochrome B5 ◽  
Electrochemical Analysis ◽  
Monooxygenase System ◽  
Protein Protein Interactions ◽  
Reduction Potentials ◽  
Drug Biotransformation ◽  
Redox Partners

Molecular interactions between proteins redox partners (cytochromes Р450 3А4, 3А5 and cytochrome b5) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes Р450 3A4 and 3А5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b5: the microsomal (b5mc) and mitochondrial (b5om) forms of this protein, as well as with 2 “chimeric” proteins, b5(om-mc), b5(mc-om). Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om. Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om, b5(om-mc), and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435  -0.350 V (vs. Ag/AgCl). Cytochrome b5mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 in the presence of its substrate testosterone.

Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes

2014 ◽  
Vol 60 (1) ◽  
pp. 17-27 ◽  
Author(s):  
O.V. Gnedenko ◽  
A.S. Ivanov ◽  
E.O. Yablokov ◽  
S.A. Usanov ◽  
D.V. Mukha ◽  
...  
Keyword(s):  
Cytochrome B ◽  
Protein Interactions ◽  
Dissociation Constants ◽  
Cytochromes P450 ◽  
Electrochemical Analysis ◽  
Monooxygenase System ◽  
Protein Protein Interactions ◽  
Reduction Potentials ◽  
Drug Biotransformation ◽  
Redox Partners

Molecular interactions between proteins redox partners (cytochromes Р450 3А4, 3А5 and cytochrome b ) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes Р450 3А4 and 3А5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b : the microsomal ( b5mc ) and mitochondrial ( b5om ) forms of this protein, as well as with 2 “chimeric” proteins, b5(om-mc) , b5(mc-om) . Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om . Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om , b5(om-mc) , and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435- -0.350 V (vs. Ag/AgCl). Cytochrome b mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 to testosterone.

scholarly journals Biosensor selection of small compounds, modulating a complex formation between cytochrome P450s and NADPH-dependent P450 oxidoreductase

2020 ◽  
Vol 3 (3) ◽  
pp. e00134
Author(s):  
P.V. Ershov ◽  
E.O. Yablokov ◽  
Y.V. Mezentsev ◽  
L.A. Kaluzhskiy ◽  
A.Ya. Luschik ◽  
...  
Keyword(s):  
Complex Formation ◽  
Protein Interactions ◽  
Cytochromes P450 ◽  
Cytochrome B5 ◽  
Clinical Importance ◽  
Dissociation Rate ◽  
Monooxygenase System ◽  
P450 Monooxygenase ◽  
P450 Oxidoreductase ◽  
First Choice

The study of the effect of low-molecular-weight compounds (substrates, endogenous metabolites, drugs and xenobiotics) on the kinetic and equilibrium parameters of functionally significant binary protein-protein interactions (PPIs) is of both fundamental and clinical importance. The surface plasmon resonance (SPR) is the method of the first choice for studying PPIs. Earlier, SPR analysis revealed the modulating effect of steroidal substrates on the affinity of interactions between steroidogenic microsomal cytochromes P450 (CYP) and their redox partner (cytochrome b5). In this work, we have shown the suitability of the experimental approach for assessing the selective effect of the cofactor NADPH on the interaction between cytochromes CYP3A4 or CYP2E1 with NADPH-dependent P450 oxidoreductase (CPR). Experiments have shown that the CYP3A4/CPR complex is not modulated by NADPH, while the dissociation rate of the CYP2E1/CPR complex in the presence of NADPH significantly decreased: the koff values in the absence and presence of NADPH were (3.6 ± 0.2) • 10-3 s-1 and (3.8 ± 0.2) • 10-4 s-1, respectively. Thus, in the presence of NADPH, an increase in the affinity of CYP2E1/CPR complex formation by approximately one order of magnitude was observed, while NADPH did not affect the kon value of this complex. Co-injection of NADPH at the CYP2E1/CPR complex preformed in the absence of NADPH had minor influence on the koff values (<10%). This suggests a stabilizing role of NADPH for the CYP2E1/CPR complex formation. Thus, the use of our approach made it possible to assess the effect of the main electron supplier for the microsomal cytochrome P450 monooxygenase system on the kinetic rate constants of CYP/CPR complexes.

Molecular Recognition in the P450cam Monooxygenase System: Direct Monitoring of Protein–Protein Interactions by Using Optical Biosensor

2001 ◽  
Vol 391 (2) ◽  
pp. 255-264 ◽  
Author(s):  
Yuri D. Ivanov ◽  
Irina P. Kanaeva ◽  
Irina I. Karuzina ◽  
Alexander I. Archakov ◽  
Gaston Hui Bon Hoa ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Protein Interactions ◽  
Optical Biosensor ◽  
Monooxygenase System ◽  
Protein Protein Interactions

scholarly journals Probing the flavin transfer mechanism in alkanesulfonate monooxygenase system

2018 ◽  
Author(s):  
PV Dayal ◽  
HR Ellis
Keyword(s):  
Protein Interactions ◽  
Active Site ◽  
Lag Phase ◽  
Monooxygenase System ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Loop Region ◽  
Alkanesulfonate Monooxygenase ◽  
Α Helix

AbstractBacteria acquire sulfur through the sulfur assimilation pathway, but under sulfur limiting conditions bacteria must acquire sulfur from alternative sources. The alkanesulfonate monooxygenase enzymes are expressed under sulfur-limiting conditions, and catalyze the desulfonation of wide-range of alkanesulfonate substrates. The SsuE enzyme is an NADPH-dependent FMN reductase that provides reduced flavin to the SsuD monooxygenase. The mechanism for the transfer of reduced flavin in flavin dependent two-component systems occurs either by free-diffusion or channeling. Previous studies have shown the presence of protein-protein interactions between SsuE and SsuD, but the identification of putative interaction sights have not been investigated. Current studies utilized HDX-MS to identify protective sites on SsuE and SsuD. A conserved α-helix on SsuD showed a decrease in percent deuteration when SsuE was included in the reaction. This suggests the role of α-helix in promoting protein-protein interactions. Specific SsuD variants were generated in order to investigate the role of these residues in protein-protein interactions and catalysis. Variant containing substitutions at the charged residues showed a six-fold decrease in the activity, while a deletion variant of SsuD lacking the α-helix showed no activity when compared to wild-type SsuD. In addition, there was no protein-protein interactions identified between SsuE and his-tagged SsuD variants in pull-down assays, which correlated with an increase in the Kd value. The α-helix is located right next to a dynamic loop region, positioned at the entrance of the active site. The putative interaction site and dynamic loop region located so close to the active site of SsuD suggests the importance of this region in the SsuD catalysis. Stopped-flow studies were performed to analyze the lag-phase which signifies the stabilization and transfer of reduced flavin from SsuE to SsuD. The SsuD variants showed a decrease in lag-phase, which could be because of a downturn in flavin transfer. A competitive assay was devised to evaluate the mechanism of flavin transfer in the alkanesulfonate monooxygenase system. A variant of SsuE was generated which interacted with SsuD, but was not able to reduce FMN. Assays that included varying concentrations of Y118A SsuE and wild-type SsuE in the coupled assays showed a decrease in the desulfonation activity of SsuD. The decrease in activity could be by virtue of Y118A SsuE competing with the wild-type SsuE for the putative docking site on SsuD. These studies define the importance of protein-protein interactions for the efficient transfer of reduced flavin from SsuE to SsuD leading to the desulfonation of alkanesulfonates.

SPR analysis of protein-protein interactions with P450 cytochromes and cytochrome b5 integrated into lipid membrane

2019 ◽  
Vol 65 (5) ◽  
pp. 374-379
Author(s):  
L.A. Kaluzhskiy ◽  
P.V. Ershov ◽  
K.S. Kurpedinov ◽  
D.S. Sonina ◽  
E.O. Yablokov ◽  
...  
Keyword(s):  
Complex Formation ◽  
Protein Interactions ◽  
Internal Control ◽  
Lipid Membrane ◽  
Dissociation Constants ◽  
Cytochrome B5 ◽  
Monooxygenase System ◽  
Protein Protein Interactions ◽  
Surface Distribution ◽  
Chip Type

Identification of new protein-protein interactions (PPI) and characterization of quantitative parameters of complex formation represent one of central tasks of protein interactomics. This work is a logical continuation of the cycle of our previous works devoted to the study of PPIs among the components of cytochrome P450-dependent monooxygenase system. Using an optical biosensor of Surface Plasmon Resonance (SPR biosensor), a comparative analysis on the determination of kinetic and equilibrium parameters of complex formation between the membrane-bound hemoprotein cytochrome b5 with cytochrome P450s was performed using two different protocols for protein immobilization: 1) covalent non-oriented one on to the carboxymethyl dextran chip type CM and 2) non-covalent oriented immobilization in the lipid environment on the chip type L1 with internal control of liposomes surface distribution. In the second protocol it was shown that the complex formation was characterized by 2.5 times higher affinity due to an decrease in rate dissociation constants. The appropriateness of using both experimental models is discussed.

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