1
|
Delinois LJ, De León-Vélez O, Vázquez-Medina A, Vélez-Cabrera A, Marrero-Sánchez A, Nieves-Escobar C, Alfonso-Cano D, Caraballo-Rodríguez D, Rodriguez-Ortiz J, Acosta-Mercado J, Benjamín-Rivera JA, González-González K, Fernández-Adorno K, Santiago-Pagán L, Delgado-Vergara R, Torres-Ávila X, Maser-Figueroa A, Grajales-Avilés G, Miranda Méndez GI, Santiago-Pagán J, Nieves-Santiago M, Álvarez-Carrillo V, Griebenow K, Tinoco AD. Cytochrome c: Using Biological Insight toward Engineering an Optimized Anticancer Biodrug. INORGANICS 2021; 9:83. [PMID: 35978717 PMCID: PMC9380692 DOI: 10.3390/inorganics9110083] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The heme protein cytochrome c (Cyt c) plays pivotal roles in cellular life and death processes. In the respiratory chain of mitochondria, it serves as an electron transfer protein, contributing to the proliferation of healthy cells. In the cell cytoplasm, it activates intrinsic apoptosis to terminate damaged cells. Insight into these mechanisms and the associated physicochemical properties and biomolecular interactions of Cyt c informs on the anticancer therapeutic potential of the protein, especially in its ability to subvert the current limitations of small molecule-based chemotherapy. In this review, we explore the development of Cyt c as an anticancer drug by identifying cancer types that would be receptive to the cytotoxicity of the protein and factors that can be finetuned to enhance its apoptotic potency. To this end, some information is obtained by characterizing known drugs that operate, in part, by triggering Cyt c induced apoptosis. The application of different smart drug delivery systems is surveyed to highlight important features for maintaining Cyt c stability and activity and improving its specificity for cancer cells and high drug payload release while recognizing the continuing limitations. This work serves to elucidate on the optimization of the strategies to translate Cyt c to the clinical market.
Collapse
Affiliation(s)
- Louis J. Delinois
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Omar De León-Vélez
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Adriana Vázquez-Medina
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Alondra Vélez-Cabrera
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Amanda Marrero-Sánchez
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | | | - Daniela Alfonso-Cano
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | | | - Jael Rodriguez-Ortiz
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Jemily Acosta-Mercado
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Josué A. Benjamín-Rivera
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Kiara González-González
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Kysha Fernández-Adorno
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Lisby Santiago-Pagán
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Rafael Delgado-Vergara
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Xaiomy Torres-Ávila
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Andrea Maser-Figueroa
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | | | | | - Javier Santiago-Pagán
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Miguel Nieves-Santiago
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Vanessa Álvarez-Carrillo
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Kai Griebenow
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| | - Arthur D. Tinoco
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, Río Piedras, PR 00931, USA
| |
Collapse
|
2
|
Kimura H, Nagasato N, Kato N, Kojima M, Enomoto C, Nakata E, Takashima H. Photophysical and elecron-transfer reaction properties of tris(2,2’-bipyridine)ruthenium(II)-based inhibitors that covalently bound to the active site of chymotrypsin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2021.100027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
3
|
Sławski J, Białek R, Burdziński G, Gibasiewicz K, Worch R, Grzyb J. Competition between Photoinduced Electron Transfer and Resonance Energy Transfer in an Example of Substituted Cytochrome c-Quantum Dot Systems. J Phys Chem B 2021; 125:3307-3320. [PMID: 33760623 PMCID: PMC8041302 DOI: 10.1021/acs.jpcb.1c00325] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Colloidal quantum
dots (QDs) are nanoparticles that are able to
photoreduce redox proteins by electron transfer (ET). QDs are also
able to transfer energy by resonance energy transfer (RET). Here,
we address the question of the competition between these two routes
of QDs’ excitation quenching, using cadmium telluride QDs and
cytochrome c (CytC) or its metal-substituted derivatives. We used
both oxidized and reduced versions of native CytC, as well as fluorescent,
nonreducible Zn(II)CytC, Sn(II)CytC, and metal-free porphyrin CytC.
We found that all of the CytC versions quench QD fluorescence, although
the interaction may be described differently in terms of static and
dynamic quenching. QDs may be quenchers of fluorescent CytC derivatives,
with significant differences in effectiveness depending on QD size.
SnCytC and porphyrin CytC increased the rate of Fe(III)CytC photoreduction,
and Fe(II)CytC slightly decreased the rate and ZnCytC presence significantly
decreased the rate and final level of reduced FeCytC. These might
be partially explained by the tendency to form a stable complex between
protein and QDs, which promoted RET and collisional quenching. Our
findings show that there is a net preference for photoinduced ET over
other ways of energy transfer, at least partially, due to a lack of
donors, regenerating a hole at QDs and leading to irreversibility
of ET events. There may also be a common part of pathways leading
to photoinduced ET and RET. The nature of synergistic action observed
in some cases allows the hypothesis that RET may be an additional
way to power up the ET.
Collapse
Affiliation(s)
- Jakub Sławski
- Department of Biophysics, Faculty of Biotechnology, University of Wrocław, ul. F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Rafał Białek
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Gotard Burdziński
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Krzysztof Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Remigiusz Worch
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Joanna Grzyb
- Department of Biophysics, Faculty of Biotechnology, University of Wrocław, ul. F. Joliot-Curie 14a, 50-383 Wrocław, Poland
| |
Collapse
|
4
|
Suwa M, Imamura N, Awano P, Nakata E, Takashima H. Photoinduced electron-transfer reactions of tris(2,2′-bipyridine)ruthenium(II)-based carbonic anhydrase inhibitors tethering plural binding sites. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mikiko Suwa
- Department of Chemistry, Faculty of Science; Nara Women's University; Nara Japan
| | - Narumi Imamura
- Department of Chemistry, Faculty of Science; Nara Women's University; Nara Japan
| | - Pirika Awano
- Department of Chemistry, Faculty of Science; Nara Women's University; Nara Japan
| | - Eiji Nakata
- Institute of Advanced Energy; Kyoto University; Kyoto Japan
| | - Hiroshi Takashima
- Department of Chemistry, Faculty of Science; Nara Women's University; Nara Japan
| |
Collapse
|
5
|
Page TR, Hoffman BM. Control of cyclic photoinitiated electron transfer between cytochrome c peroxidase (W191F) and cytochrome c by formation of dynamic binary and ternary complexes. Biochemistry 2015; 54:1188-97. [PMID: 25629200 DOI: 10.1021/bi500888y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Extensive studies of the physiological protein-protein electron-transfer (ET) complex between yeast cytochrome c peroxidase (CcP) and cytochrome c (Cc) have left unresolved questions about how formation and dissociation of binary and ternary complexes influence ET. We probe this issue through a study of the photocycle of ET between Zn-protoporphyrin IX-substituted CcP(W191F) (ZnPCcP) and Cc. Photoexcitation of ZnPCcP in complex with Fe(3+)Cc initiates the photocycle: charge-separation ET, [(3)ZnPCcP, Fe(3+)Cc] → [ZnP(+)CcP, Fe(2+)Cc], followed by charge recombination, [ZnP(+)CcP, Fe(2+)Cc] → [ZnPCcP, Fe(3+)Cc]. The W191F mutation eliminates fast hole hopping through W191, enhancing accumulation of the charge-separated intermediate and extending the time scale for binding and dissociation of the charge-separated complex. Both triplet quenching and the charge-separated intermediate were monitored during titrations of ZnPCcP with Fe(3+)Cc, Fe(2+)Cc, and redox-inert CuCc. The results require a photocycle that includes dissociation and/or recombination of the charge-separated binary complex and a charge-separated ternary complex, [ZnP(+)CcP, Fe(2+)Cc, Fe(3+)Cc]. The expanded kinetic scheme formalizes earlier proposals of "substrate-assisted product dissociation" within the photocycle. The measurements yield the thermodynamic affinity constants for binding the first and second Cc: KI = 10(-7) M(-1), and KII = 10(-4) M(-1). However, two-site analysis of the thermodynamics of formation of the ternary complex reveals that Cc binds at the weaker-binding site with much greater affinity than previously recognized and places upper bounds on the contributions of repulsion between the two Cc's of the ternary complex. In conjunction with recent nuclear magnetic resonance studies, the analysis further suggests a dynamic view of the ternary complex, wherein neither Cc necessarily faithfully adopts the crystal-structure configuration because of Cc-Cc repulsion.
Collapse
Affiliation(s)
- Taylor R Page
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | | |
Collapse
|
6
|
Takashima H, Fukuda M, Nakagaki F, Ogata T, Tsukahara K. Photoinduced Electron-Transfer Reactions of Carbonic Anhydrase Inhibitor Containing Tris(2,2′-bipyridine)ruthenium(II) Analogue. J Phys Chem B 2013; 117:2625-35. [DOI: 10.1021/jp310604w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
| | - Misa Fukuda
- Department of Chemistry, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
| | - Fumie Nakagaki
- Department of Chemistry, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
| | - Tomoko Ogata
- Department of Chemistry, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
| | - Keiichi Tsukahara
- Department of Chemistry, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan
| |
Collapse
|
7
|
Volkov AN, Nicholls P, Worrall JA. The complex of cytochrome c and cytochrome c peroxidase: The end of the road? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1482-503. [DOI: 10.1016/j.bbabio.2011.07.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 07/21/2011] [Accepted: 07/22/2011] [Indexed: 11/25/2022]
|
8
|
|
9
|
Takashima H, Shibata S, Sekiguchi Y, Imai Y, Tsukahara K. Direct Comparison of Chiral Substituent Effects for Viologens in Stereoselective Photoinduced Electron-Transfer Reactions with Zinc Myoglobin. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.1250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
10
|
Takashima H, Kawahara H, Kitano M, Shibata S, Murakami H, Tsukahara K. Metal ion-dependent fluorescent dynamics of photoexcited zinc-porphyrin and zinc-myoglobin modified with ethylenediaminetetraacetic acid. J Phys Chem B 2009; 112:15493-502. [PMID: 18991435 DOI: 10.1021/jp807692w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reconstituted zinc-myoglobin (ZnMb) dyads, ZnMb-[M(II)(edta)], have been prepared by incorporating a zinc-porphyrin (ZnP) cofactor modified with ethylenediaminetetraacetic acid (H(4)edta) into apo-Mb. In case of the monomeric ZnP(edta) cofactor coordinated by one pyridine molecule, ZnP(py)(edta), a spontaneous 1:1 complex with a transient metal ion was formed in an aqueous solvent, and the photoexcited singlet state of ZnP, (1)(ZnP)*, was quenched by the [Cu(II)(edta)] moiety through intramolecular photoinduced electron-transfer (ET) reaction. The rate constant for the intramolecular quenching ET (k(q)) at 25 degrees C was successfully obtained as k(q) = 5.1 x 10(9) s(-1). In the case of Co(2+), Ni(2+), and Mn(2+), intersystem crossing by paramagnetic effect was mainly considered between (1)(ZnP)* and the [M(II)(edta)] complex. For the ZnMb-[M(II)(edta)] systems, the intramolecular ET reaction between the excited singlet state of (1)(ZnMb)* and the [Cu(II)(edta)] moieties provided the slower quenching rate constant, k(q) = 2.1 x 10(8) s(-1), compared with that of the ZnP(py)(edta) one. Kinetic studies also presented the efficient fluorescence quenching of the (1)(ZnMb)*-[Co(II)(edta)] dyad. Our study clearly demonstrates that wrapping of the ZnP cofactor by the apoprotein matrix and synthetic manipulation at the Mb surface ensure metal ion-sensitive fluorescent dynamics of ZnMb and provides valuable information to elucidate the complicated mechanism of the biological photoinduced ET reactions of hemoproteins.
Collapse
Affiliation(s)
- Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara, 630-8506 Japan.
| | | | | | | | | | | |
Collapse
|
11
|
Ferreira JAB. Structural effects of biologically relevant rhodamines on spectroscopy of fluorescence fluctuations. Ann N Y Acad Sci 2008; 1130:85-90. [PMID: 18596336 DOI: 10.1196/annals.1430.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Exciton coupling in pi-pi complexes between the indole ring and other pi systems is known to enhance the efficiency of energy and electron transfer. Rhodamines' xanthylium rings allow the formation of weakly or nonfluorescent complexes with the amino acid tryptophan. Thus, because of the short distance of the participating electronic clouds, intrinsic electron transfer-induced fluorescence quenching occurs. In solution, the rate constant of electron transfer is known to be limited by collision interactions at the contact distance. By contrast, in protein local environments tryptophan residues can be either exposed or buried in hydrophobic regions. Herein, I report on the properties of aromatic derivatized rhodamines, among which is one with a bound phenylalanine amino acid group. Encompassed is the spectroscopic and kinetic information in bulk and at the single-molecule levels both in free solution and in the presence of human serum albumin. Spectroscopic characteristics are focused with special emphasis on enhanced fluorescence that is addressed considering optimized geometries and electronic spectra. The importance of the probes associated with peptides and metal ions both in condensed phase or interfaces and as substrates with proteins is put into perspective.
Collapse
Affiliation(s)
- José A B Ferreira
- Centro de Química Estrutural, Complexo Interdisciplinar, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001, Lisbon, Portugal.
| |
Collapse
|
12
|
Volkov AN, Worrall JAR, Holtzmann E, Ubbink M. Solution structure and dynamics of the complex between cytochrome c and cytochrome c peroxidase determined by paramagnetic NMR. Proc Natl Acad Sci U S A 2006; 103:18945-50. [PMID: 17146057 PMCID: PMC1748157 DOI: 10.1073/pnas.0603551103] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The physiological complex of yeast cytochrome c peroxidase and iso-1-cytochrome c is a paradigm for biological electron transfer. Using paramagnetic NMR spectroscopy, we have determined the conformation of the protein complex in solution, which is shown to be very similar to that observed in the crystal structure [Pelletier H, Kraut J (1992) Science 258:1748-1755]. Our results support the view that this transient electron transfer complex is dynamic. The solution structure represents the dominant protein-protein orientation, which, according to our estimates, is occupied for >70% of the lifetime of the complex, with the rest of the time spent in the dynamic encounter state. Based on the observed paramagnetic effects, we have delineated the conformational space sampled by the protein molecules during the dynamic part of the interaction, providing experimental support for the theoretical predictions of the classical Brownian dynamics study [Northrup SH, Boles JO, Reynolds JCL (1988) Science 241:67-70]. Our findings corroborate the dynamic behavior of this complex and offer an insight into the mechanism of the protein complex formation in solution.
Collapse
Affiliation(s)
- Alexander N. Volkov
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Jonathan A. R. Worrall
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Elodie Holtzmann
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
13
|
Takashima H, Araki A, Takemoto K, Yoshikawa N, Tsukahara K. Stereoselective and driving-force-dependent photoinduced electron-transfer reactions of zinc myoglobin with optically active N,N′-dimethylcinchoninium and N,N′-dimethylcinchonidinium ions. J Biol Inorg Chem 2006; 11:316-24. [PMID: 16491378 DOI: 10.1007/s00775-006-0079-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Accepted: 12/30/2005] [Indexed: 11/25/2022]
Abstract
In order to understand the detailed mechanism of the stereoselective photoinduced electron-transfer (ET) reactions of zinc-substituted myoglobin (ZnMb) with optically active molecules by flash photolysis, we designed and prepared new optically active agents, such as N,N'-dimethylcinchoninium diiodide ([MCN]I2) and N,N'-dimethylcinchonidinium diiodide ([MCD]I2). The photoexcited triplet state of ZnMb, 3(ZnMb)*, was successfully quenched by [MCN]2+ and [MCD]2+ ions to form the radical pair of ZnMb cation (ZnMb.+) and reduced [MCN].+ and [MCD].+, followed by a thermal back ET reaction to the ground state. The rate constants (kq) for the ET quenching at 25 degrees C were obtained as kq(MCN)=(1.9+/-0.1)x10(6) M-1 s-1 and kq(MCD)=(3.0+/-0.2)x10(6) M-1 s-1, respectively. The ratio of kq(MCD)/kq(MCN)=1.6 indicates that the [MCD]2+ preferentially quenches 3ZnMb)*. The second-order rate constants (kb) for the thermal back ET reaction from [MCN].+ and [MCD].+ to ZnMb.+ at 25 degrees C were kb(MCN)=(0.79+/-0.04)x10(8) M-1 s-1 and kb(MCD)=(1.0+/-0.1)x10(8) M-1 s-1, respectively, and the selectivity was kq(MCD)/kq(MCN)=1.3. Both quenching and thermal back ET reactions are controlled by the ET step. In the quenching reaction, the energy differences of DeltaDeltaH ( not equal)(MCD-MCN) and DeltaDeltaS ( not equal)(MCD-MCN) at 25 degrees C were obtained as -1.1 and 0 kJ mol-1, respectively. On the other hand, DeltaDeltaH (not equal)(MCD-MCN)=11+/-2 kJ mol-1 and TDeltaDeltaS (not equal)(MCD-MCN)=-10+/-2 kJ mol-1 were given in the thermal back ET reaction. The highest stereoselectivity of 1.7 for [MCD].+ found at low temperature (10 degrees C) was due to the DeltaDeltaS ( not equal) value obtained in the thermal back ET reaction.
Collapse
Affiliation(s)
- Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara, 630-8506, Japan.
| | | | | | | | | |
Collapse
|
14
|
Prudêncio M, Ubbink M. Transient complexes of redox proteins: structural and dynamic details from NMR studies. J Mol Recognit 2004; 17:524-39. [PMID: 15386621 DOI: 10.1002/jmr.686] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Redox proteins participate in many metabolic routes, in particular those related to energy conversion. Protein-protein complexes of redox proteins are characterized by a weak affinity and a short lifetime. Two-dimensional NMR spectroscopy has been applied to many redox protein complexes, providing a wealth of information about the process of complex formation, the nature of the interface and the dynamic properties of the complex. These studies have shown that some complexes are non-specific and exist as a dynamic ensemble of orientations while in other complexes the proteins assume a single orientation. The binding interface in these complexes consists of a small hydrophobic patch for specificity, surrounded by polar, uncharged residues that may enhance dissociation, and, in most complexes, a ring or patch of charged residues that enhances the association by electrostatic interactions. The entry and exit port of the electrons is located within the hydrophobic interaction site, ensuring rapid electron transfer from one redox centre to the next.
Collapse
Affiliation(s)
- Miguel Prudêncio
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, PO Box 9502, 2300 RA Leiden, The Netherlands
| | | |
Collapse
|
15
|
Guo M, Bhaskar B, Li H, Barrows TP, Poulos TL. Crystal structure and characterization of a cytochrome c peroxidase-cytochrome c site-specific cross-link. Proc Natl Acad Sci U S A 2004; 101:5940-5. [PMID: 15071191 PMCID: PMC395902 DOI: 10.1073/pnas.0306708101] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Indexed: 11/18/2022] Open
Abstract
A specific covalently cross-linked complex between redox partners yeast cytochrome c peroxidase (CCP) and cytochrome c (cyt. c) has been made by engineering cysteines into CCP and cyt. c that form an intermolecular disulfide bond in high yield. The crystal structure of the cross-linked complex has been solved to 1.88-A resolution and closely resembles the structure of the noncovalent complex [Pellitier, H. & Kraut, J. (1992) Science 258, 1748-1755]. The higher resolution of the covalent complex has enabled the location of ordered water molecules at the peroxidase-cytochrome c interface that serve to bridge between the two proteins by hydrogen bonding. As in the noncovalent complex, direct electrostatic interactions between protein groups appear not to be critical in complex formation. UV-visible spectroscopic and stopped-flow studies indicate that CCP in the covalent complex reacts normally with H(2)O(2) to give compound I. Stopped-flow kinetic studies also show that intramolecular electron transfer between the cross-linked ferrocytochrome c and the Trp-191 cation radical site in CCP compound I occurs fast and is nearly complete within the dead time ( approximately 2 ms) of the instrument. These results indicate that the structure of the covalent complex closely mimics the physiological electron transfer complex. In addition, single-turnover and steady-state experiments reveal that CCP compound I in the covalent complex oxidizes exogenously added ferrocytochrome c at a slow rate (t(1/2) approximately 2 min), indicating that CCP does not have a second independent site for physiologically relevant electron transfer.
Collapse
Affiliation(s)
- Maolin Guo
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | | | | | | | | |
Collapse
|
16
|
Takashima H, Tanaka M, Hasegawa Y, Tsukahara K. Remarkably stereoselective photoinduced electron-transfer reaction between zinc myoglobin and optically active binaphthyl bisviologen. J Biol Inorg Chem 2003; 8:499-506. [PMID: 12764600 DOI: 10.1007/s00775-003-0441-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2002] [Accepted: 12/30/2002] [Indexed: 11/30/2022]
Abstract
We have designed and synthesized new optically active bisviologens ([BNMV](4+)) containing a binaphthyl moiety to examine the stereoselective photoinduced electron-transfer (ET) reactions with zinc-substituted myoglobin (ZnMb) by flash photolysis. The photoexcited triplet state of ZnMb, (3)(ZnMb)*, was successfully quenched by [BNMV](4+) ions to form the radical pair of a ZnMb cation (ZnMb(.+)) and a reduced viologen ([BNMV](.3+)), followed by a thermal ET reaction to the ground state. The rate constants ( k(q)) for the ET quenching at 25 degrees C were obtained as k(q)( R)=(2.9+/-0.2)x10(7) M(-1) s(-1) and k(q)( S)=(2.2+/-0.2)x10(7) M(-1) s(-1), respectively. The ratio of k(q)( R)/ k(q)( S)=1.3 indicates that the ( R)-isomer of the chiral viologen preferentially quenches (3)(ZnMb)*. On the other hand, the rate constants ( k) for the thermal ET reaction from [BNMV](.3+) to ZnMb(-+) at 25 degrees C were k( R)=(1.2+/-0.1)x10(8) M(-1) s(-1) and k( S)=(0.47+/-0.03)x10(8) M(-1) s(-1), respectively, and the ratio remarkably increased to k( R)/ k( S)=2.6. The activation parameters, Delta H(not equal) and Delta S(not equal), were determined from the kinetic measurements at various temperatures (10-30 degrees C) to understand the ET mechanisms. In the quenching reaction, the energy differences of Delta Delta H*(R- S) and T Delta Delta S*( R- S) at 25 degrees C were calculated to be -3.9+/-1.6 and -3.3+/-0.2 kJ mol(-1), respectively, whereas Delta Delta H*( R-S)=7.7+/-1.9 kJ mol(-1 )and T Delta Delta S*( R-S)=9.9+/-0.5 kJ mol(-1 )were found for the thermal ET reaction. Therefore, the thermal ET reaction to the ground state was proved to be dominated by the entropy term, and the large stereoselectivity may arise from the decrease in charge repulsion between donor and acceptor.
Collapse
Affiliation(s)
- Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women's University, 630-8506, Nara , Japan.
| | - Michiru Tanaka
- Department of Chemistry, Faculty of Science, Nara Women's University, 630-8506, Nara , Japan
| | - Yuko Hasegawa
- Department of Chemistry, Faculty of Science, Nara Women's University, 630-8506, Nara , Japan
| | - Keiichi Tsukahara
- Department of Chemistry, Faculty of Science, Nara Women's University, 630-8506, Nara , Japan
| |
Collapse
|
17
|
Sarkar B, Mukhopadhyay P, Bharadwaj PK. Laterally non-symmetric aza-cryptands: synthesis, catalysis and derivatization to new receptors. Coord Chem Rev 2003. [DOI: 10.1016/s0010-8545(02)00058-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
18
|
Faro M, Frago S, Mayoral T, Hermoso JA, Sanz-Aparicio J, Gómez-Moreno C, Medina M. Probing the role of glutamic acid 139 of Anabaena ferredoxin-NADP+ reductase in the interaction with substrates. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4938-47. [PMID: 12383252 DOI: 10.1046/j.1432-1033.2002.03194.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The role of the negative charge of the E139 side-chain of Anabaena Ferredoxin-NADP+ reductase (FNR) in steering appropriate docking with its substrates ferredoxin, flavodoxin and NADP+/H, that leads to efficient electron transfer (ET) is analysed by characterization of several E139 FNR mutants. Replacement of E139 affects the interaction with the different FNR substrates in very different ways. Thus, while E139 does not appear to be involved in the processes of binding and ET between FNR and NADP+/H, the nature and the conformation of the residue at position 139 of Anabaena FNR modulates the precise enzyme interaction with the protein carriers ferredoxin (Fd) and flavodoxin (Fld). Introduction of the shorter aspartic acid side-chain at position 139 produces an enzyme that interacts more weakly with both ET proteins. Moreover, the removal of the charge, as in the E139Q mutant, or the charge-reversal mutation, as in E139K FNR, apparently enhances additional interaction modes of the enzyme with Fd, and reduces the possible orientations with Fld to more productive and stronger ones. Hence, removal of the negative charge at position 139 of Anabaena FNR produces a deleterious effect in its ET reactions with Fd whereas it appears to enhance the ET processes with Fld. Significantly, a large structural variation is observed for the E139 side-chain conformer in different FNR structures, including the E139K mutant. In this case, a positive potential region replaces a negative one in the wild-type enzyme. Our observations further confirm the contribution of both attractive and repulsive interactions in achieving the optimal orientation for efficient ET between FNR and its protein carriers.
Collapse
Affiliation(s)
- Merche Faro
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Spain
| | | | | | | | | | | | | |
Collapse
|
19
|
Hurley JK, Morales R, Martínez-Júlvez M, Brodie TB, Medina M, Gómez-Moreno C, Tollin G. Structure-function relationships in Anabaena ferredoxin/ferredoxin:NADP(+) reductase electron transfer: insights from site-directed mutagenesis, transient absorption spectroscopy and X-ray crystallography. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:5-21. [PMID: 12034466 DOI: 10.1016/s0005-2728(02)00188-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The interaction between reduced Anabaena ferredoxin and oxidized ferredoxin:NADP(+) reductase (FNR), which occurs during photosynthetic electron transfer (ET), has been investigated extensively in the authors' laboratories using transient and steady-state kinetic measurements and X-ray crystallography. The effect of a large number of site-specific mutations in both proteins has been assessed. Many of the mutations had little or no effect on ET kinetics. However, non-conservative mutations at three highly conserved surface sites in ferredoxin (F65, E94 and S47) caused ET rate constants to decrease by four orders of magnitude, and non-conservative mutations at three highly conserved surface sites in FNR (L76, K75 and E301) caused ET rate constants to decrease by factors of 25-150. These residues were deemed to be critical for ET. Similar mutations at several other conserved sites in the two proteins (D67 in Fd; E139, L78, K72, and R16 in FNR) caused smaller but still appreciable effects on ET rate constants. A strong correlation exists between these results and the X-ray crystal structure of an Anabaena ferredoxin/FNR complex. Thus, mutations at sites that are within the protein-protein interface or are directly involved in interprotein contacts generally show the largest kinetic effects. The implications of these results for the ET mechanism are discussed.
Collapse
Affiliation(s)
- John K Hurley
- Department of Biochemistry and Molecular Biophysics, University of Arizona, 1041 E. Lowell Street, Tucson, AZ 85721-0088, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
The association of two biological macromolecules is a fundamental biological phenomenon and an unsolved theoretical problem. Docking methods for ab initio prediction of association of two independently determined protein structures usually fail when they are applied to a large set of complexes, mostly because of inaccuracies in the scoring function and/or difficulties on simulating the rearrangement of the interface residues on binding. In this work we present an efficient pseudo-Brownian rigid-body docking procedure followed by Biased Probability Monte Carlo Minimization of the ligand interacting side-chains. The use of a soft interaction energy function precalculated on a grid, instead of the explicit energy, drastically increased the speed of the procedure. The method was tested on a benchmark of 24 protein-protein complexes in which the three-dimensional structures of their subunits (bound and free) were available. The rank of the near-native conformation in a list of candidate docking solutions was <20 in 85% of complexes with no major backbone motion on binding. Among them, as many as 7 out of 11 (64%) protease-inhibitor complexes can be successfully predicted as the highest rank conformations. The presented method can be further refined to include the binding site predictions and applied to the structures generated by the structural proteomics projects. All scripts are available on the Web.
Collapse
Affiliation(s)
- Juan Fernández-Recio
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | | | | |
Collapse
|
21
|
Hancock JT, Desikan R, Neill SJ. Does the redox status of cytochrome C act as a fail-safe mechanism in the regulation of programmed cell death? Free Radic Biol Med 2001; 31:697-703. [PMID: 11522455 DOI: 10.1016/s0891-5849(01)00646-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
It has now become recognized that one of the key events in the induction of apoptosis, or programmed cell death, in both plants and animals is the release of cytochrome c from mitochondria. It is also known that oxidative stress imposed on cells can have a profound effect on the onset or progression of apoptosis. Here, we discuss how the redox status of cytochrome c, and thus its structure, can be altered by the presence of reactive oxygen species (ROS) and reduced glutathione (GSH). We suggest that cytochrome c will only induce programmed cell death if present in the cytoplasm in the oxidized state, and that the presence of high levels of cytoplasmic GSH maintain cytochrome c in an inactive (reduced) state, thus behaving as a fail-safe mechanism if cytochrome c is released by mitochondria when programmed cell death is not the required outcome. If the redox status of the cell is disturbed however, perhaps in the presence of hydrogen peroxide, GSH concentrations will drop, the cellular E(h) will rise, and cytochrome c will tend towards the oxidized state, allowing programmed cell death to proceed. Therefore, we propose that the redox state of cytoplasmic cytochrome c may be a key regulator of programmed cell death.
Collapse
Affiliation(s)
- J T Hancock
- Centre for Research in Plant Science, Faculty of Applied Science, University of the West of England, Bristol, UK.
| | | | | |
Collapse
|
22
|
Chand DK, Bharadwaj PK, Schneider HJ. Cryptands and related tripodal ligands: interaction with nucleic acids and nuclease activity of their Eu(III) complexes. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00630-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
23
|
Stemp ED, Barton JK. The flash-quench technique in protein-DNA electron transfer: reduction of the guanine radical by ferrocytochrome c. Inorg Chem 2000; 39:3868-74. [PMID: 11196782 DOI: 10.1021/ic0000698] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Electron transfer from a protein to oxidatively damaged DNA, specifically from ferrocytochrome c to the guanine radical, was examined using the flash-quench technique. Ru(phen)2dppz2+ (dppz = dipyridophenazine) was employed as the photosensitive intercalator, and ferricytochrome c (Fe3+ cyt c), as the oxidative quencher. Using transient absorption and time-resolved luminescence spectroscopies, we examined the electron-transfer reactions following photoexcitation of the ruthenium complex in the presence of poly(dA-dT) or poly(dG-dC). The luminescence-quenching titrations of excited Ru(phen)2dppz2+ by Fe3+ cyt c are nearly identical for the two DNA polymers. However, the spectral characteristics of the long-lived transient produced by the quenching depend strongly upon the DNA. For poly(dA-dT), the transient has a spectrum consistent with formation of a [Ru(phen)2dppz3+, Fe2+ cyt c] intermediate, indicating that the system regenerates itself via electron transfer from the protein to the Ru(III) metallointercalator for this polymer. For poly(dG-dC), however, the transient has the characteristics expected for an intermediate of Fe2+ cyt c and the neutral guanine radical. The characteristics of the transient formed with the GC polymer are consistent with rapid oxidation of guanine by the Ru(III) complex, followed by slow electron transfer from Fe2+ cyt c to the guanine radical. These experiments show that electron holes on DNA can be repaired by protein and demonstrate how the flash-quench technique can be used generally in studying electron transfer from proteins to guanine radicals in duplex DNA.
Collapse
Affiliation(s)
- E D Stemp
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | | |
Collapse
|
24
|
Nocek JM, Leesch VW, Zhou JS, Jiang M, Hoffman BM. Multi-domain binding of cytochromecperoxidase by cytochromec: Thermodynamic vs. microscopic binding constants. Isr J Chem 2000. [DOI: 10.1560/7apr-817l-luje-2u6l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
25
|
Tremain SM, Kostić NM. Fate of the excited triplet state of zinc cytochrome c in the presence of iron(III), iron(II), iron-free, and heme-free forms of cytochrome c. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(00)00012-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
26
|
Salameh AS, Ghaddar T, Isied SS. Hydrogen bonding association of a ruthenium(II) bipyridine barbituric acid guest to complementary 2,6-diaminopyridine amide hosts: guidelines for designing high binding hydrogen bonding cavities in both high-and low-polarity solvents. J PHYS ORG CHEM 1999. [DOI: 10.1002/(sici)1099-1395(199903)12:3<247::aid-poc122>3.0.co;2-u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
27
|
Moore GR, Cox MC, Crowe D, Osborne MJ, Rosell FI, Bujons J, Barker PD, Mauk MR, Mauk AG. N epsilon,N epsilon-dimethyl-lysine cytochrome c as an NMR probe for lysine involvement in protein-protein complex formation. Biochem J 1998; 332 ( Pt 2):439-49. [PMID: 9601073 PMCID: PMC1219499 DOI: 10.1042/bj3320439] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The reductively dimethylated derivatives of horse and yeast iso-1-ferricytochromes c have been prepared and characterized for use as NMR probes of the complexes formed by cytochrome c with bovine liver cytochrome b5 and yeast cytochrome c peroxidase. The electrostatic properties and structures of the derivatized cytochromes are not significantly perturbed by the modifications; neither are the electrostatics of protein-protein complex formation or rates of interprotein electron transfer. Two-dimensional 1H-13C NMR spectroscopy of the complexes formed by the derivatized cytochromes with cytochrome b5 and cytochrome c peroxidase has been used to investigate the number and identity of lysine residues of cytochrome c that are involved in interprotein interactions of cytochrome c. The NMR data are incompatible with simple static models proposed previously for the complexes formed by these proteins, but are consistent with the presence of multiple, interconverting complexes of comparable stability, consistent with studies employing Brownian dynamics to model the complexes. The NMR characteristics of the Nepsilon,Nepsilon-dimethyl-lysine groups, their chemical shift dispersion, oxidation state and temperature dependences and the possibility of chemical exchange phenomena are discussed with relevance to the utility of Nepsilon, Nepsilon-dimethyl-lysine's being a generally useful derivative for characterizing protein-protein complexes.
Collapse
Affiliation(s)
- G R Moore
- School of Chemical Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Nocek JM, Zhou JS, Hoffman BM. Quenching as a four-dimensional experiment: application to the multi-domain binding of cytochrome c by cytochrome c peroxidase. J Electroanal Chem (Lausanne) 1997. [DOI: 10.1016/s0022-0728(96)05054-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
29
|
Kluck RM, Martin SJ, Hoffman BM, Zhou JS, Green DR, Newmeyer DD. Cytochrome c activation of CPP32-like proteolysis plays a critical role in a Xenopus cell-free apoptosis system. EMBO J 1997; 16:4639-49. [PMID: 9303308 PMCID: PMC1170090 DOI: 10.1093/emboj/16.15.4639] [Citation(s) in RCA: 313] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
Collapse
Affiliation(s)
- R M Kluck
- Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA
| | | | | | | | | | | |
Collapse
|
30
|
|
31
|
Crnogorac MM, Shen C, Young S, Hansson O, Kostić NM. Effects of mutations in plastocyanin on the kinetics of the protein rearrangement gating the electron-transfer reaction with zinc cytochrome c. Analysis of the rearrangement pathway. Biochemistry 1996; 35:16465-74. [PMID: 8987979 DOI: 10.1021/bi961914u] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We study, by flash kinetic spectrophotometry on the microsecond time scale, the effects of ionic strength and viscosity on the kinetics of oxidative quenching of the triplet state of zinc cytochrome c (3Zncyt) by the wild-type form and the following nine mutants of cupriplastocyanin: Leu12Glu, Leu12Asn, Phe35Tyr, Gln88Glu, Tyr83Phe, Tyr83His, Asp42Asn, Glu43Asn, and the double mutant Glu59Lys/Glu60Gln. The unimolecular rate constants for the quenching reactions within the persistent diprotein complex, which predominates at low ionic strengths, and within the transient diprotein complex, which is involved at higher ionic strengths, are equal irrespective of the mutation. Evidently, the two complexes are the same. In both reactions, the rate-limiting step is rearrangement of the diprotein complex from a configuration optimal for docking to the one optimal for the subsequent electron-transfer step, which is fast. We investigate the effects of plastocyanin mutations on this rearrangement, which gates the overall electron-transfer reaction. Conversion of the carboxylate anions into amide groups in the lower acidic cluster (residues 42 and 43), replacement of Tyr83 with other aromatic residues, and mutations in the hydrophobic patch in plastocyanin do not significantly affect the rearrangement. Conversion of a pair of carboxylate anions into a cationic and a neutral residue in the upper acidic cluster (residues 59 and 60) impedes the rearrangement. Creation of an anion at position 88, between the upper acidic cluster and the hydrophobic patch, facilitates the rearrangement. The rate constant for the rearrangement smoothly decreases as the solution viscosity increases, irrespective of the mutation. Fittings of this dependence to the modified Kramers's equation and to an empirical equation show that zinc cytochrome c follows the same trajectory on the surfaces of all the plastocyanin mutants but that the obstacles along the way vary as mutations alter the electrostatic potential. Mutations that affect protein association (i.e., change the binding constant) do not necessarily affect the reaction between the associated proteins (i.e., the rate constant) and vice versa. All of the kinetic and thermodynamic effects and noneffects of mutations consistently indicate that in the protein rearrangement the basic patch of zinc cytochrome c moves from a position between the two acidic clusters to a position at or near the upper acidic cluster.
Collapse
Affiliation(s)
- M M Crnogorac
- Department of Chemistry, Iowa State University, Ames 50011, USA
| | | | | | | | | |
Collapse
|
32
|
Ivković-Jensen MM, Kostić NM. Effects of temperature on the kinetics of the gated electron-transfer reaction between zinc cytochrome c and plastocyanin. Analysis of configurational fluctuation of the diprotein complex. Biochemistry 1996; 35:15095-106. [PMID: 8942677 DOI: 10.1021/bi961608g] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This is a study of the effects of temperature (in the range 273.3-307.7 K) and of ionic strength (in the range 2.5-100 mM) on the kinetics of photoinduced electron-transfer reaction 3Zncyt/pc(II)--> Zncyt+/pc(I) within the electrostatic complex of zinc cytochrome c and cupriplastocyanin at pH 7.0. In order to separate direct and indirect effects of temperature on the rate constants, viscosity of the solutions was fixed, at different values, by additions of sucrose. The activation parameters for the reaction within the preformed complex, at the low ionic strength, are delta H++ = 13 +/- 2 kJ/mol and delta S++ = -97 +/- 4 J/K mol. The activation parameters for the reaction within the encounter complex, at the higher ionic strength, are delta H++ = 13 +/- 1 kJ/mol and delta S++ = -96 +/- 3 J/K mol. Evidently, the two complexes are the same. The proteins associate similarly in the persistent and the transient complex, i.e., at different ionic strengths. In both complexes, however, electron transfer is gated by a rearrangement, as previous studies from this laboratory showed. Changes in the solution viscosity modulate this rearrangement by affecting delta H++, not delta S++. The activation parameters are analyzed by empirical methods. The thermodynamic parameters delta H and delta S for the formation of the complex Zncyt/pc(II) are determined and related to changes in hydrophilic and hydrophobic surfaces upon protein association in three configurations. A difference between the values of delta H for the configuration providing optimal electronic coupling between the redox sites and the configuration providing optimal docking equals the experimental value delta H++ = 13 kJ/mol for the rearrangement of the latter configuration into the former. Enthalpy of activation may reflect a change in the character of the exposed surface as the diprotein complex rearranges. Entropy of activation may reflect tightening of the contact between the associated proteins.
Collapse
|
33
|
Turro C, Bossmann SH, Niu S, Barton JK, Turro NJ. Effect of guest/host interactions on photoinduced electron transfer reactions. Inorganica Chim Acta 1996. [DOI: 10.1016/s0020-1693(96)05332-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
34
|
Shen C, Kostić NM. Reductive Quenching of the Triplet State of Zinc Cytochrome c by the Hexacyanoferrate(II) Anion and by Conjugate Bases of Ethylenediaminetetraacetic Acid. Inorg Chem 1996. [DOI: 10.1021/ic9510270] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chengyu Shen
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Nenad M. Kostić
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| |
Collapse
|
35
|
Lahiri J, Fate GD, Ungashe SB, Groves JT. Multi-Heme Self-Assembly in Phospholipid Vesicles. J Am Chem Soc 1996. [DOI: 10.1021/ja953092e] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joydeep Lahiri
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Gwendolyn D. Fate
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - Solomon B. Ungashe
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| | - John T. Groves
- Contribution from the Department of Chemistry, Princeton University, Princeton, New Jersey 08544
| |
Collapse
|