1
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Mammoser CC, Agh RE, Garcia NM, Wang Y, Thielges M. Altered coordination in a blue copper protein upon association with redox partner revealed by carbon-deuterium vibrational probes. Phys Chem Chem Phys 2022; 24:21588-21592. [DOI: 10.1039/d2cp03314c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proteins tune the reactivity of metal sites; less understood is the impact of association with a redox partner. We demonstrate the utility of carbon-deuterium labels for selective analysis of delicate...
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2
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Erv1 and Cytochrome c Mediate Rapid Electron Transfer via A Collision-Type Interaction. J Mol Biol 2021; 433:167045. [PMID: 33971209 DOI: 10.1016/j.jmb.2021.167045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/01/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022]
Abstract
Being essential for oxidative protein folding in the mitochondrial intermembrane space, the mitochondrial disulfide relay relies on the electron transfer (ET) from the sulfhydryl oxidase Erv1 to cytochrome c (Cc). Using solution NMR spectroscopy, we demonstrate that while the yeast Cc-Erv1 system is functionally active, no observable binding of the protein partners takes place. The transient interaction between Erv1 and Cc can be rationalized by molecular modeling, suggesting that a large surface area of Erv1 can sustain a fast ET to Cc via a collision-type mechanism, without the need for a canonical protein complex formation. We suggest that, by preventing the direct ET to molecular oxygen (O2), the collision-type Cc-Erv1 interaction plays a role in protecting the organism against reactive oxygen species.
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3
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van Son M, Schilder JT, Di Savino A, Blok A, Ubbink M, Huber M. The Transient Complex of Cytochrome c and Cytochrome c Peroxidase: Insights into the Encounter Complex from Multifrequency EPR and NMR Spectroscopy. Chemphyschem 2020; 21:1060-1069. [PMID: 32301564 PMCID: PMC7317791 DOI: 10.1002/cphc.201901160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/03/2020] [Indexed: 12/31/2022]
Abstract
We present a novel approach to study transient protein-protein complexes with standard, 9 GHz, and high-field, 95 GHz, electron paramagnetic resonance (EPR) and paramagnetic NMR at ambient temperatures and in solution. We apply it to the complex of yeast mitochondrial iso-1-cytochrome c (Cc) with cytochrome c peroxidase (CcP) with the spin label [1-oxyl-2,2,5,5-tetramethyl-Δ3-pyrroline-3-methyl)-methanethiosulfonate] attached at position 81 of Cc (SL-Cc). A dissociation constant KD of 20±4×10-6 M (EPR and NMR) and an equal amount of stereo-specific and encounter complex (NMR) are found. The EPR spectrum of the fully bound complex reveals that the encounter complex has a significant population (60 %) that shares important features, such as the Cc-interaction surface, with the stereo-specific complex.
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Affiliation(s)
- Martin van Son
- Leiden Institute of Physics, Huygens-Kamerlingh Onnes LaboratoryLeiden UniversityNiels Bohrweg 22333 CALeiden (TheNetherlands
| | - Jesika T. Schilder
- Leiden Institute of ChemistryLeiden University, Gorlaeus LaboratoriesEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Antonella Di Savino
- Leiden Institute of ChemistryLeiden University, Gorlaeus LaboratoriesEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Anneloes Blok
- Leiden Institute of ChemistryLeiden University, Gorlaeus LaboratoriesEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Marcellus Ubbink
- Leiden Institute of ChemistryLeiden University, Gorlaeus LaboratoriesEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Martina Huber
- Leiden Institute of Physics, Huygens-Kamerlingh Onnes LaboratoryLeiden UniversityNiels Bohrweg 22333 CALeiden (TheNetherlands
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4
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Ramos S, Le Sueur AL, Horness RE, Specker JT, Collins JA, Thibodeau KE, Thielges MC. Heterogeneous and Highly Dynamic Interface in Plastocyanin-Cytochrome f Complex Revealed by Site-Specific 2D-IR Spectroscopy. J Phys Chem B 2019; 123:2114-2122. [PMID: 30742428 DOI: 10.1021/acs.jpcb.8b12157] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Transient protein complexes are crucial for sustaining dynamic cellular processes. The complexes of electron-transfer proteins are a notable example, such as those formed by plastocyanin (Pc) and cytochrome f (cyt f) in the photosynthetic apparatus. The dynamic and heterogeneous nature of these complexes, however, makes their study challenging. To better elucidate the complex of Nostoc Pc and cyt f, 2D-IR spectroscopy coupled to site-specific labeling with cyanophenylalanine infrared (IR) probes was employed to characterize how the local environments at sites along the surface of Pc were impacted by cyt f binding. The results indicate that Pc most substantially engages with cyt f via the hydrophobic patch around the copper redox site. Complexation with cyt f led to an increase in inhomogeneous broadening of the probe absorptions, reflective of increased heterogeneity of interactions with their environment. Notably, most of the underlying states interconverted very rapidly (1 to 2 ps), suggesting a complex with a highly mobile interface. The data support a model of the complex consisting of a large population of an encounter complex. Additionally, the study demonstrates the application of 2D-IR spectroscopy with site-specifically introduced probes to reveal new quantitative insight about dynamic biochemical systems.
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Affiliation(s)
- Sashary Ramos
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Amanda L Le Sueur
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Rachel E Horness
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Jonathan T Specker
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Jessica A Collins
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Katherine E Thibodeau
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
| | - Megan C Thielges
- Indiana University , Department of Chemistry , Bloomington , Indiana 47405 , United States
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5
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Foerster J, Poehner I, Ullmann GM. MCMap-A Computational Tool for Mapping Energy Landscapes of Transient Protein-Protein Interactions. ACS OMEGA 2018; 3:6465-6475. [PMID: 31458826 PMCID: PMC6644659 DOI: 10.1021/acsomega.8b00572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/22/2018] [Indexed: 06/10/2023]
Abstract
MCMap is a tool particularly well-suited for analyzing energy landscapes of transient macromolecular complexes. The program applies a Monte Carlo strategy, where the ligand moves randomly in the electrostatic field of the receptor. By applying importance sampling, the major interaction sites are mapped, resulting in a global distribution of ligand-receptor complexes. This approach displays the dynamic character of transiently interacting protein complexes where not a single complex but an ensemble of complexes better describes the protein interactions. The software provides a broad range of analysis options which allow for relating the simulations to experimental data and for interpreting them on a structural level. The application of MCMap is exemplified by the electron-transfer complex of cytochrome c peroxidase and cytochrome c from baker's yeast. The functionality of MCMap and the visualization of simulation data are in particular demonstrated by studying the dependence of the association on ionic strength and on the oxidation state of the binding partner. Furthermore, microscopically, a repulsion of a second ligand can be seen in the ternary complex upon the change of the oxidation state of the bound cytochrome c. The software is made available as open source software together with the example and can be downloaded free of charge from http://www.bisb.uni-bayreuth.de/index.php?page=downloads.
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6
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Le Sueur AL, Ramos S, Ellefsen JD, Cook S, Thielges MC. Evaluation of p-(13C,15N-Cyano)phenylalanine as an Extended Time Scale 2D IR Probe of Proteins. Anal Chem 2017; 89:5254-5260. [DOI: 10.1021/acs.analchem.6b04650] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Amanda L. Le Sueur
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Sashary Ramos
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jonathan D. Ellefsen
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Silas Cook
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Megan C. Thielges
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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7
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Identification of productive and futile encounters in an electron transfer protein complex. Proc Natl Acad Sci U S A 2017; 114:E1840-E1847. [PMID: 28223532 DOI: 10.1073/pnas.1616813114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Well-defined, stereospecific states in protein complexes are often in exchange with an ensemble of more dynamic orientations: the encounter states. The structure of the stereospecific complex between cytochrome P450cam and putidaredoxin was solved recently by X-ray diffraction as well as paramagnetic NMR spectroscopy. Other than the stereospecific complex, the NMR data clearly show the presence of additional states in the complex in solution. In these encounter states, populated for a small percentage of the time, putidaredoxin assumes multiple orientations and samples a large part of the surface of cytochrome P450cam. To characterize the nature of the encounter states, an extensive paramagnetic NMR dataset has been analyzed using the Maximum Occurrence of Regions methodology. The analysis reveals the location and maximal spatial extent of the additional states needed to fully explain the NMR data. Under the assumption of sparsity of the size of the conformational ensemble, several minor states can be located quite precisely. The distribution of these minor states correlates with the electrostatic potential map around cytochrome P450cam. Whereas some minor states are on isolated positively charged patches, others are connected to the stereospecific site via positively charged paths. The existence of electrostatically favorable pathways between the stereospecific interaction site and the different minor states or lack thereof suggests a means to discriminate between productive and futile encounter states.
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8
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Le Sueur AL, Schaugaard RN, Baik MH, Thielges MC. Methionine Ligand Interaction in a Blue Copper Protein Characterized by Site-Selective Infrared Spectroscopy. J Am Chem Soc 2016; 138:7187-93. [PMID: 27164303 DOI: 10.1021/jacs.6b03916] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The reactivity of metal sites in proteins is tuned by protein-based ligands. For example, in blue copper proteins such as plastocyanin (Pc), the structure imparts a highly elongated bond between the Cu and a methionine (Met) axial ligand to modulate its redox properties. Despite extensive study, a complete understanding of the contribution of the protein to redox activity is challenged by experimentally accessing both redox states of metalloproteins. Using infrared (IR) spectroscopy in combination with site-selective labeling with carbon-deuterium (C-D) vibrational probes, we characterized the localized changes at the Cu ligand Met97 in the oxidized and reduced states, as well as the Zn(II) or Co(II)-substituted, the pH-induced low-coordinate, the apoprotein, and the unfolded states. The IR absorptions of (d3-methyl)Met97 are highly sensitive to interaction of the sulfur-based orbitals with the metal center and are demonstrated to be useful reporters of its modulation in the different states. Unrestricted Kohn-Sham density functional theory calculations performed on a model of the Cu site of Pc confirm the observed dependence. IR spectroscopy was then applied to characterize the impact of binding to the physiological redox partner cytochrome (cyt) f. The spectral changes suggest a slightly stronger Cu-S(Met97) interaction in the complex with cyt f that has potential to modulate the electron transfer properties. Besides providing direct, molecular-level comparison of the oxidized and reduced states of Pc from the perspective of the axial Met ligand and evidence for perturbation of the Cu site properties by redox partner binding, this study demonstrates the localized spatial information afforded by IR spectroscopy of selectively incorporated C-D probes.
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Affiliation(s)
- Amanda L Le Sueur
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Richard N Schaugaard
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Mu-Hyun Baik
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Megan C Thielges
- Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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9
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Schilder J, Ubbink M. Weak self-association of cytochrome c peroxidase molecules observed by paramagnetic NMR. JOURNAL OF BIOMOLECULAR NMR 2016; 65:29-40. [PMID: 27236778 PMCID: PMC4908164 DOI: 10.1007/s10858-016-0035-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/03/2016] [Indexed: 06/05/2023]
Abstract
There is growing experimental evidence that many proteins exhibit a tendency for (ultra)weak homo- or hetero- oligomerization interactions. With the development of paramagnetic relaxation enhancement NMR spectroscopy it has become possible to characterize weak complexes experimentally and even detect complexes with affinities in the 1-25 mM range. We present evidence for a weak complex between cytochrome c peroxidase (CcP) molecules. In a previous study, we attached nitroxide based spin labels at three positions on CcP with the intent of observing intramolecular PRE effects. However, several intermolecular PRE effects were also observed suggesting a weak self-association between CcP molecules. The CcP-CcP complex was characterized using paramagnetic NMR and protein docking. The interaction occurs between the surface that is also part of the stereo-specific binding site for its physiological partner, cytochrome c (Cc), and several small, positively charged patches on the "back" of CcP. The CcP-CcP complex is not a stereo-specific complex. It is a dynamic ensemble of orientations, characteristic of an encounter state. The contact areas resemble those observed for CcP molecules in crystals. The CcP-CcP complex formation competes with that of the CcP-Cc complex. However, the affinity for Cc is much larger and thus it is expected that, under physiological conditions, auto-inhibition will be limited. A weak self-association between cytochrome c peroxidase molecules was characterized using paramagnetic NMR.
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Affiliation(s)
- Jesika Schilder
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Marcellus Ubbink
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
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10
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Schilder J, Liu WM, Kumar P, Overhand M, Huber M, Ubbink M. Protein docking using an ensemble of spin labels optimized by intra-molecular paramagnetic relaxation enhancement. Phys Chem Chem Phys 2016; 18:5729-42. [DOI: 10.1039/c5cp03781f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The effect of spin label mobility on the accuracy of protein–protein docking calculations was investigated using inter- and intra-molecular PRE data.
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Affiliation(s)
- Jesika Schilder
- Leiden Institute of Chemistry
- Leiden University
- Gorlaeus Laboratories
- 2333 CC Leiden
- The Netherlands
| | - Wei-Min Liu
- Leiden Institute of Chemistry
- Leiden University
- Gorlaeus Laboratories
- 2333 CC Leiden
- The Netherlands
| | - Pravin Kumar
- Department of Physics
- Huygens-Kamerlingh Onnes Laboratory
- Leiden University
- 2333 CA Leiden
- The Netherlands
| | - Mark Overhand
- Leiden Institute of Chemistry
- Leiden University
- Gorlaeus Laboratories
- 2333 CC Leiden
- The Netherlands
| | - Martina Huber
- Department of Physics
- Huygens-Kamerlingh Onnes Laboratory
- Leiden University
- 2333 CA Leiden
- The Netherlands
| | - Marcellus Ubbink
- Leiden Institute of Chemistry
- Leiden University
- Gorlaeus Laboratories
- 2333 CC Leiden
- The Netherlands
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11
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Huang R, Zhang M, Rwere F, Waskell L, Ramamoorthy A. Kinetic and structural characterization of the interaction between the FMN binding domain of cytochrome P450 reductase and cytochrome c. J Biol Chem 2014; 290:4843-4855. [PMID: 25512382 DOI: 10.1074/jbc.m114.582700] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cytochrome P450 reductase (CPR) is a diflavin enzyme that transfers electrons to many protein partners. Electron transfer from CPR to cyt c has been extensively used as a model reaction to assess the redox activity of CPR. CPR is composed of multiple domains, among which the FMN binding domain (FBD) is the direct electron donor to cyt c. Here, electron transfer and complex formation between FBD and cyt c are investigated. Electron transfer from FBD to cyt c occurs at distinct rates that are dependent on the redox states of FBD. When compared with full-length CPR, FBD reduces cyt c at a higher rate in both the semiquinone and hydroquinone states. The NMR titration experiments reveal the formation of dynamic complexes between FBD and cyt c on a fast exchange time scale. Chemical shift mapping identified residues of FBD involved in the binding interface with cyt c, most of which are located in proximity to the solvent-exposed edge of the FMN cofactor along with other residues distributed around the surface of FBD. The structural model of the FBD-cyt c complex indicates two possible orientations of complex formation. The major complex structure shows a salt bridge formation between Glu-213/Glu-214 of FBD and Lys-87 of cyt c, which may be essential for the formation of the complex, and a predicted electron transfer pathway mediated by Lys-13 of cyt c. The findings provide insights into the function of CPR and CPR-cyt c interaction on a structural basis.
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Affiliation(s)
- Rui Huang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Meng Zhang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Freeborn Rwere
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Lucy Waskell
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and.
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12
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Bashir Q, Meulenbroek EM, Pannu NS, Ubbink M. Engineering specificity in a dynamic protein complex with a single conserved mutation. FEBS J 2014; 281:4892-905. [DOI: 10.1111/febs.13028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/09/2014] [Accepted: 08/27/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Qamar Bashir
- Gorlaeus Laboratories; Leiden Institute of Chemistry; Leiden University; The Netherlands
| | | | - Navraj S. Pannu
- Gorlaeus Laboratories; Leiden Institute of Chemistry; Leiden University; The Netherlands
| | - Marcellus Ubbink
- Gorlaeus Laboratories; Leiden Institute of Chemistry; Leiden University; The Netherlands
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13
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The dynamic complex of cytochrome c6 and cytochrome f studied with paramagnetic NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1305-15. [DOI: 10.1016/j.bbabio.2014.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/13/2014] [Accepted: 03/16/2014] [Indexed: 11/23/2022]
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14
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Guan JY, Foerster JM, Drijfhout JW, Timmer M, Blok A, Ullmann GM, Ubbink M. An Ensemble of Rapidly Interconverting Orientations in Electrostatic Protein-Peptide Complexes Characterized by NMR Spectroscopy. Chembiochem 2014; 15:556-66. [DOI: 10.1002/cbic.201300623] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Indexed: 12/21/2022]
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15
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Hiruma Y, Hass MA, Kikui Y, Liu WM, Ölmez B, Skinner SP, Blok A, Kloosterman A, Koteishi H, Löhr F, Schwalbe H, Nojiri M, Ubbink M. The Structure of the Cytochrome P450cam–Putidaredoxin Complex Determined by Paramagnetic NMR Spectroscopy and Crystallography. J Mol Biol 2013; 425:4353-65. [DOI: 10.1016/j.jmb.2013.07.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 11/27/2022]
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16
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Scanu S, Foerster JM, Timmer M, Ullmann GM, Ubbink M. Loss of electrostatic interactions causes increase of dynamics within the plastocyanin-cytochrome f complex. Biochemistry 2013; 52:6615-26. [PMID: 23984801 DOI: 10.1021/bi400450q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent studies on the electron transfer complex formed by cytochrome f and plastocyanin from Nostoc revealed that both hydrophobic and electrostatic interactions play a role in the process of complex formation. To study the balance between these two types of interactions in the encounter and the final state, the complex between plastocyanin from Phormidium laminosum and cytochrome f from Nostoc sp. PCC 7119 was investigated using NMR spectroscopy and Monte Carlo docking. Cytochrome f has a highly negative charge. Phormidium plastocyanin is similar to that from Nostoc, but the net charge of the protein is negative rather than positive. NMR titrations of Zn-substituted Phormidium plastocyanin and Nostoc cytochrome f indicated that a complex with an affinity intermediate between those of the Nostoc and Phormidium complexes is formed. Plastocyanin was found in a head-on orientation, as determined using pseudocontact shifts, similar to that in the Phormidium complex, in which the hydrophobic patch represents the main site of interaction on plastocyanin. However, the interaction in the cross-complex is dependent on electrostatics, similar to that in the Nostoc complex. The negative charge of plastocyanin decreases, but not abolishes, the attraction to cytochrome f, resulting in the formation of a more diffuse encounter complex than in the Nostoc case, as could be determined using paramagnetic relaxation spectroscopy. This work illustrates the subtle interplay of electrostatic and hydrophobic interactions in the formation of transient protein complexes. The results are discussed in the context of a model for association on the basis of hydrophobic contacts in the encounter state.
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Affiliation(s)
- Sandra Scanu
- Institute of Chemistry, Leiden University , Einsteinweg 55, 2333 CC Leiden, The Netherlands
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17
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Schilder J, Ubbink M. Formation of transient protein complexes. Curr Opin Struct Biol 2013; 23:911-8. [PMID: 23932200 DOI: 10.1016/j.sbi.2013.07.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 01/16/2023]
Abstract
The encounter complex of two proteins is a dynamic intermediate state that guides proteins to their binding site, thus enhancing the rate of complex formation. It is particularly useful for complexes that must balance a biological requirement for high turnover with the need for specific binding, such as electron transfer complexes. Here, we describe the current methods for studying and visualizing encounter complexes. We discuss recent developments in mapping the energy landscapes, the role of hydrophobic interactions during encounter complex formation and the discovery of futile encounter complexes. These studies have not only provided insight into encounter complexes of electron transfer proteins, but also opened up new questions and approaches for studying encounter complexes in other weakly associated proteins.
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Affiliation(s)
- Jesika Schilder
- Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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18
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Scanu S, Foerster JM, Ullmann GM, Ubbink M. Role of Hydrophobic Interactions in the Encounter Complex Formation of the Plastocyanin and Cytochrome f Complex Revealed by Paramagnetic NMR Spectroscopy. J Am Chem Soc 2013; 135:7681-92. [DOI: 10.1021/ja4015452] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sandra Scanu
- Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden,
The Netherlands
| | - Johannes M. Foerster
- Structural
Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse
30, 95447 Bayreuth, Germany
| | - G. Matthias Ullmann
- Structural
Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse
30, 95447 Bayreuth, Germany
| | - Marcellus Ubbink
- Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden,
The Netherlands
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19
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Saen-Oon S, Lucas MF, Guallar V. Electron transfer in proteins: theory, applications and future perspectives. Phys Chem Chem Phys 2013; 15:15271-85. [DOI: 10.1039/c3cp50484k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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