1
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Henderson R, Anasti K, Manne K, Stalls V, Saunders C, Bililign Y, Williams A, Bubphamala P, Montani M, Kachhap S, Li J, Jaing C, Newman A, Cain DW, Lu X, Venkatayogi S, Berry M, Wagh K, Korber B, Saunders KO, Tian M, Alt F, Wiehe K, Acharya P, Alam SM, Haynes BF. Engineering immunogens that select for specific mutations in HIV broadly neutralizing antibodies. Nat Commun 2024; 15:9503. [PMID: 39489734 DOI: 10.1038/s41467-024-53120-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 09/27/2024] [Indexed: 11/05/2024] Open
Abstract
Vaccine development targeting rapidly evolving pathogens such as HIV-1 requires induction of broadly neutralizing antibodies (bnAbs) with conserved paratopes and mutations, and in some cases, the same Ig-heavy chains. The current trial-and-error search for immunogen modifications that improve selection for specific bnAb mutations is imprecise. Here, to precisely engineer bnAb boosting immunogens, we use molecular dynamics simulations to examine encounter states that form when antibodies collide with the HIV-1 Envelope (Env). By mapping how bnAbs use encounter states to find their bound states, we identify Env mutations predicted to select for specific antibody mutations in two HIV-1 bnAb B cell lineages. The Env mutations encode antibody affinity gains and select for desired antibody mutations in vivo. These results demonstrate proof-of-concept that Env immunogens can be designed to directly select for specific antibody mutations at residue-level precision by vaccination, thus demonstrating the feasibility of sequential bnAb-inducing HIV-1 vaccine design.
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Affiliation(s)
- Rory Henderson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Kara Anasti
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Kartik Manne
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Victoria Stalls
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Carrie Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Yishak Bililign
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Ashliegh Williams
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Pimthada Bubphamala
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Maya Montani
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Sangita Kachhap
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Jingjing Li
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Chuancang Jaing
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Amanda Newman
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Derek W Cain
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Xiaozhi Lu
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Sravani Venkatayogi
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Madison Berry
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Kshitij Wagh
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Bette Korber
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
- The New Mexico Consortium, Los Alamos, NM, USA
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Ming Tian
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Fred Alt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
- Department of Biochemistry, Duke University, Durham, NC, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
- Department of Pathology, Duke University School of Medicine, Durham, NC, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA.
- Department of Immunology, Duke University Medical Center, Durham, NC, USA.
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2
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Henderson R, Anasti K, Manne K, Stalls V, Saunders C, Bililign Y, Williams A, Bubphamala P, Montani M, Kachhap S, Li J, Jaing C, Newman A, Cain D, Lu X, Venkatayogi S, Berry M, Wagh K, Korber B, Saunders KO, Tian M, Alt F, Wiehe K, Acharya P, Alam SM, Haynes BF. Engineering immunogens that select for specific mutations in HIV broadly neutralizing antibodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571700. [PMID: 38168268 PMCID: PMC10760096 DOI: 10.1101/2023.12.15.571700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Vaccine development targeting rapidly evolving pathogens such as HIV-1 requires induction of broadly neutralizing antibodies (bnAbs) with conserved paratopes and mutations, and, in some cases, the same Ig-heavy chains. The current trial-and-error search for immunogen modifications that improve selection for specific bnAb mutations is imprecise. To precisely engineer bnAb boosting immunogens, we used molecular dynamics simulations to examine encounter states that form when antibodies collide with the HIV-1 Envelope (Env). By mapping how bnAbs use encounter states to find their bound states, we identified Env mutations that were predicted to select for specific antibody mutations in two HIV-1 bnAb B cell lineages. The Env mutations encoded antibody affinity gains and selected for desired antibody mutations in vivo. These results demonstrate proof-of-concept that Env immunogens can be designed to directly select for specific antibody mutations at residue-level precision by vaccination, thus demonstrating the feasibility of sequential bnAb-inducing HIV-1 vaccine design.
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Affiliation(s)
- Rory Henderson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Kara Anasti
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kartik Manne
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Victoria Stalls
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Carrie Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Yishak Bililign
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashliegh Williams
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Pimthada Bubphamala
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Maya Montani
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Sangita Kachhap
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Jingjing Li
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Chuancang Jaing
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Amanda Newman
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Derek Cain
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Xiaozhi Lu
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Sravani Venkatayogi
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Madison Berry
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kshitij Wagh
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- The New Mexico Consortium, Los Alamos, NM, 87544 USA
| | - Bette Korber
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- The New Mexico Consortium, Los Alamos, NM, 87544 USA
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Ming Tian
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Fred Alt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
- Department of Biochemistry, Duke University, Durham, NC 27710, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
- Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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3
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Mishra RP, Goel G. Multiscale Model for Quantitative Prediction of Insulin Aggregation Nucleation Kinetics. J Chem Theory Comput 2021; 17:7886-7898. [PMID: 34813303 DOI: 10.1021/acs.jctc.1c00499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We combined kinetic, thermodynamic, and structural information from single-molecule (protein folding) and two-molecule (association) explicit-solvent simulations for determination of kinetic parameters in protein aggregation nucleation with insulin as the model protein. A structural bioinformatics approach was developed to account for heterogeneity of aggregation-prone species, with the transition complex theory found applicable in modeling association kinetics involving non-native species. Specifically, the kinetic pathway for formation of aggregation-prone oligomeric species was found to contain a structurally specific dominant binding mode, making the kinetic process similar to native protein association. The kinetic parameters thus obtained were used in a population balance model, and accurate predictions for aggregation nucleation time varying over 2 orders of magnitude with changes in either insulin concentration or an aggregation-inhibitor ligand concentration were obtained, while an empirical parameter set was not found to be transferable for prediction of ligand effects. Further, this physically determined kinetic parameter set provided several mechanistic insights, such as identification of the rate-limiting step in aggregation nucleation and a quantitative explanation for the switch from Arrhenius to non-Arrhenius aggregation kinetics around the melting temperature of insulin.
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Affiliation(s)
- Rit Pratik Mishra
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, Delhi 110016, India
| | - Gaurav Goel
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, Delhi 110016, India
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4
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Moldenhauer H, Díaz-Franulic I, Poblete H, Naranjo D. Trans-toxin ion-sensitivity of charybdotoxin-blocked potassium-channels reveals unbinding transitional states. eLife 2019; 8:46170. [PMID: 31271355 PMCID: PMC6660193 DOI: 10.7554/elife.46170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/04/2019] [Indexed: 12/11/2022] Open
Abstract
In silico and in vitro studies have made progress in understanding protein–protein complex formation; however, the molecular mechanisms for their dissociation are unclear. Protein–protein complexes, lasting from microseconds to years, often involve induced-fit, challenging computational or kinetic analysis. Charybdotoxin (CTX), a peptide from the Leiurus scorpion venom, blocks voltage-gated K+-channels in a unique example of binding/unbinding simplicity. CTX plugs the external mouth of K+-channels pore, stopping K+-ion conduction, without inducing conformational changes. Conflicting with a tight binding, we show that external permeant ions enhance CTX-dissociation, implying a path connecting the pore, in the toxin-bound channel, with the external solution. This sensitivity is explained if CTX wobbles between several bound conformations, producing transient events that restore the electrical and ionic trans-pore gradients. Wobbling may originate from a network of contacts in the interaction interface that are in dynamic stochastic equilibria. These partially-bound intermediates could lead to distinct, and potentially manipulable, dissociation pathways.
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Affiliation(s)
- Hans Moldenhauer
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ignacio Díaz-Franulic
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Horacio Poblete
- Núcleo Científico Multidisciplinario, Dirección de Investigación. Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería, and Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Universidad de Talca, Talca, Chile
| | - David Naranjo
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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5
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Strickland M, Kale S, Strub MP, Schwieters CD, Liu J, Peterkofsky A, Tjandra N. Potential Regulatory Role of Competitive Encounter Complexes in Paralogous Phosphotransferase Systems. J Mol Biol 2019; 431:2331-2342. [PMID: 31071328 DOI: 10.1016/j.jmb.2019.04.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/22/2019] [Accepted: 04/28/2019] [Indexed: 11/28/2022]
Abstract
There are two paralogous Escherichia coli phosphotransferase systems, one for sugar import (PTSsugar) and one for nitrogen regulation (PTSNtr), that utilize proteins enzyme Isugar (EIsugar) and HPr, and enzyme INtr (EINtr) and NPr, respectively. The enzyme I proteins have similar folds, as do their substrates HPr and NPr, yet they show strict specificity for their cognate partner both in stereospecific protein-protein complex formation and in reversible phosphotransfer. Here, we investigate the mechanism of specific EINtr:NPr complex formation by the study of transient encounter complexes. NMR paramagnetic relaxation enhancement experiments demonstrated transient encounter complexes of EINtr not only with the expected partner, NPr, but also with the unexpected partner, HPr. HPr occupies transient sites on EINtr but is unable to complete stereospecific complex formation. By occupying the non-productive transient sites, HPr promotes NPr transient interaction to productive sites closer to the stereospecific binding site and actually enhances specific complex formation between NPr and EINtr. The cellular level of HPr is approximately 150 times higher than that of NPr. Thus, our finding suggests a potential mechanism for cross-regulation of enzyme activity through formation of competitive encounter complexes.
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Affiliation(s)
- Madeleine Strickland
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Seyit Kale
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marie-Paule Strub
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Charles D Schwieters
- Office of Intramural Research, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jian Liu
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alan Peterkofsky
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Nico Tjandra
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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6
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Gaffney KA, Hong H. The rhomboid protease GlpG has weak interaction energies in its active site hydrogen bond network. J Gen Physiol 2018; 151:282-291. [PMID: 30420443 PMCID: PMC6400518 DOI: 10.1085/jgp.201812047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/25/2018] [Indexed: 01/24/2023] Open
Abstract
Rhomboid proteases are membrane-integrated enzymes that hydrolyze peptide bonds in the transmembrane domains of protein substrates. Gaffney and Hong experimentally determine interaction energies between active site residues to reveal weak coupling, which may explain the slow proteolysis mediated by GlpG. Intramembrane rhomboid proteases are of particular interest because of their function to hydrolyze a peptide bond of a substrate buried in the membrane. Crystal structures of the bacterial rhomboid protease GlpG have revealed a catalytic dyad (Ser201-His254) and oxyanion hole (His150/Asn154/the backbone amide of Ser201) surrounded by the protein matrix and contacting a narrow water channel. Although multiple crystal structures have been solved, the catalytic mechanism of GlpG is not completely understood. Because it is a serine protease, hydrogen bonding interactions between the active site residues are thought to play a critical role in the catalytic cycle. Here, we dissect the interaction energies among the active site residues His254, Ser201, and Asn154 of Escherichia coli GlpG, which form a hydrogen bonding network. We combine double mutant cycle analysis with stability measurements using steric trapping. In mild detergent, the active site residues are weakly coupled with interaction energies (ΔΔGInter) of ‒1.4 kcal/mol between His254 and Ser201 and ‒0.2 kcal/mol between Ser201 and Asn154. Further, by analyzing the propagation of single mutations of the active site residues, we find that these residues are important not only for function but also for the folding cooperativity of GlpG. The weak interaction between Ser and His in the catalytic dyad may partly explain the unusually slow proteolysis by GlpG compared with other canonical serine proteases. Our result suggests that the weak hydrogen bonds in the active site are sufficient to carry out the proteolytic function of rhomboid proteases.
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Affiliation(s)
- Kristen A Gaffney
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Heedeok Hong
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI .,Department of Chemistry, Michigan State University, East Lansing, MI
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7
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Tackling the Antibiotic Resistance Caused by Class A β-Lactamases through the Use of β-Lactamase Inhibitory Protein. Int J Mol Sci 2018; 19:ijms19082222. [PMID: 30061509 PMCID: PMC6121496 DOI: 10.3390/ijms19082222] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/27/2022] Open
Abstract
β-Lactams are the most widely used and effective antibiotics for the treatment of infectious diseases. Unfortunately, bacteria have developed several mechanisms to combat these therapeutic agents. One of the major resistance mechanisms involves the production of β-lactamase that hydrolyzes the β-lactam ring thereby inactivating the drug. To overcome this threat, the small molecule β-lactamase inhibitors (e.g., clavulanic acid, sulbactam and tazobactam) have been used in combination with β-lactams for treatment. However, the bacterial resistance to this kind of combination therapy has evolved recently. Therefore, multiple attempts have been made to discover and develop novel broad-spectrum β-lactamase inhibitors that sufficiently work against β-lactamase producing bacteria. β-lactamase inhibitory proteins (BLIPs) (e.g., BLIP, BLIP-I and BLIP-II) are potential inhibitors that have been found from soil bacterium Streptomyces spp. BLIPs bind and inhibit a wide range of class A β-lactamases from a diverse set of Gram-positive and Gram-negative bacteria, including TEM-1, PC1, SME-1, SHV-1 and KPC-2. To the best of our knowledge, this article represents the first systematic review on β-lactamase inhibitors with a particular focus on BLIPs and their inherent properties that favorably position them as a source of biologically-inspired drugs to combat antimicrobial resistance. Furthermore, an extensive compilation of binding data from β-lactamase–BLIP interaction studies is presented herein. Such information help to provide key insights into the origin of interaction that may be useful for rationally guiding future drug design efforts.
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8
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Complete protein-protein association kinetics in atomic detail revealed by molecular dynamics simulations and Markov modelling. Nat Chem 2017; 9:1005-1011. [PMID: 28937668 DOI: 10.1038/nchem.2785] [Citation(s) in RCA: 237] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 04/21/2017] [Indexed: 12/23/2022]
Abstract
Protein-protein association is fundamental to many life processes. However, a microscopic model describing the structures and kinetics during association and dissociation is lacking on account of the long lifetimes of associated states, which have prevented efficient sampling by direct molecular dynamics (MD) simulations. Here we demonstrate protein-protein association and dissociation in atomistic resolution for the ribonuclease barnase and its inhibitor barstar by combining adaptive high-throughput MD simulations and hidden Markov modelling. The model reveals experimentally consistent intermediate structures, energetics and kinetics on timescales from microseconds to hours. A variety of flexibly attached intermediates and misbound states funnel down to a transition state and a native basin consisting of the loosely bound near-native state and the tightly bound crystallographic state. These results offer a deeper level of insight into macromolecular recognition and our approach opens the door for understanding and manipulating a wide range of macromolecular association processes.
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9
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Moritsugu K, Terada T, Kidera A. Energy landscape of all-atom protein-protein interactions revealed by multiscale enhanced sampling. PLoS Comput Biol 2014; 10:e1003901. [PMID: 25340714 PMCID: PMC4207830 DOI: 10.1371/journal.pcbi.1003901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/22/2014] [Indexed: 11/18/2022] Open
Abstract
Protein-protein interactions are regulated by a subtle balance of complicated atomic interactions and solvation at the interface. To understand such an elusive phenomenon, it is necessary to thoroughly survey the large configurational space from the stable complex structure to the dissociated states using the all-atom model in explicit solvent and to delineate the energy landscape of protein-protein interactions. In this study, we carried out a multiscale enhanced sampling (MSES) simulation of the formation of a barnase-barstar complex, which is a protein complex characterized by an extraordinary tight and fast binding, to determine the energy landscape of atomistic protein-protein interactions. The MSES adopts a multicopy and multiscale scheme to enable for the enhanced sampling of the all-atom model of large proteins including explicit solvent. During the 100-ns MSES simulation of the barnase-barstar system, we observed the association-dissociation processes of the atomistic protein complex in solution several times, which contained not only the native complex structure but also fully non-native configurations. The sampled distributions suggest that a large variety of non-native states went downhill to the stable complex structure, like a fast folding on a funnel-like potential. This funnel landscape is attributed to dominant configurations in the early stage of the association process characterized by near-native orientations, which will accelerate the native inter-molecular interactions. These configurations are guided mostly by the shape complementarity between barnase and barstar, and lead to the fast formation of the final complex structure along the downhill energy landscape. Dynamic nature of the protein-protein interactions is an important element of cellular processes such as metabolic reactions and signal transduction, but its atomistic details are still unclear. Computational survey using molecular dynamics simulation is a straightforward method to elucidate these atomistic protein-protein interaction processes. However, a sufficient configurational sampling of the large system containing the atomistic protein complex model and explicit solvent remains a great challenge due to the long timescale involved. Here, we demonstrate that the multiscale enhanced sampling (MSES) successfully captured the atomistic details of the association/dissociation processes of a barnase-barstar complex covering the sampled space from the native complex structure to fully non-native configurations. The landscape derived from the simulation indicates that the association process is funnel-like downhill, analogously to the funnel landscape of fast-folding proteins. The funnel was found to be originated from near-native orientations guided by the shape complementarity between barnase and barstar, accelerating the formation of native inter-molecular interactions to complete the final complex structure.
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Affiliation(s)
- Kei Moritsugu
- Computational Science Research Program, RIKEN, Hirosawa, Wako, Saitama, Japan
- Graduate School of Medical Life Science, Yokohama City University, Suehiro-cho, Tsurumi-ku, Yokohama, Japan
- * E-mail:
| | - Tohru Terada
- Computational Science Research Program, RIKEN, Hirosawa, Wako, Saitama, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Akinori Kidera
- Computational Science Research Program, RIKEN, Hirosawa, Wako, Saitama, Japan
- Graduate School of Medical Life Science, Yokohama City University, Suehiro-cho, Tsurumi-ku, Yokohama, Japan
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10
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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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11
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Schilder J, Löhr F, Schwalbe H, Ubbink M. The cytochrome c peroxidase and cytochrome c encounter complex: the other side of the story. FEBS Lett 2014; 588:1873-8. [PMID: 24726731 DOI: 10.1016/j.febslet.2014.03.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/18/2014] [Accepted: 03/26/2014] [Indexed: 11/18/2022]
Abstract
Formation of an encounter complex is important for efficient protein complex formation. The encounter state consists of an ensemble of orientations of two proteins in the complex. Experimental description of such ensembles inherently suffers from insufficient data availability. We have measured paramagnetic relaxation enhancements (PRE) on cytochrome c peroxidase (CcP) caused by its partner cytochrome c (Cc) carrying a spin label. The data complement earlier PRE data of spin labelled CcP, identifying several new interactions. This work demonstrates the need of obtaining as many independent data sets as possible to achieve the most accurate description of an encounter complex.
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Affiliation(s)
- Jesika Schilder
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Frank Löhr
- Institute of Biophysical Chemistry, Goethe University Frankfurt and Centre for Biomolecular Magnetic Resonance, Max-von-Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt and Centre for Biomolecular Magnetic Resonance, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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12
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Hiruma Y, Gupta A, Kloosterman A, Olijve C, Ölmez B, Hass MAS, Ubbink M. Hot-Spot Residues in the Cytochrome P450cam-Putidaredoxin Binding Interface. Chembiochem 2013; 15:80-6. [DOI: 10.1002/cbic.201300582] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Indexed: 11/09/2022]
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13
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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] [MESH Headings] [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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14
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Clore GM, Venditti V. Structure, dynamics and biophysics of the cytoplasmic protein-protein complexes of the bacterial phosphoenolpyruvate: sugar phosphotransferase system. Trends Biochem Sci 2013; 38:515-30. [PMID: 24055245 PMCID: PMC3831880 DOI: 10.1016/j.tibs.2013.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/07/2013] [Accepted: 08/09/2013] [Indexed: 10/26/2022]
Abstract
The bacterial phosphotransferase system (PTS) couples phosphoryl transfer, via a series of bimolecular protein-protein interactions, to sugar transport across the membrane. The multitude of complexes in the PTS provides a paradigm for studying protein interactions, and for understanding how the same binding surface can specifically recognize a diverse array of targets. Fifteen years of work aimed at solving the solution structures of all soluble protein-protein complexes of the PTS has served as a test bed for developing NMR and integrated hybrid approaches to study larger complexes in solution and to probe transient, spectroscopically invisible states, including encounter complexes. We review these approaches, highlighting the problems that can be tackled with these methods, and summarize the current findings on protein interactions.
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Affiliation(s)
- G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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15
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Ahuja S, Jahr N, Im SC, Vivekanandan S, Popovych N, Le Clair SV, Huang R, Soong R, Xu J, Yamamoto K, Nanga RP, Bridges A, Waskell L, Ramamoorthy A. A model of the membrane-bound cytochrome b5-cytochrome P450 complex from NMR and mutagenesis data. J Biol Chem 2013; 288:22080-95. [PMID: 23709268 DOI: 10.1074/jbc.m112.448225] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microsomal cytochrome b5 (cytb5) is a membrane-bound protein that modulates the catalytic activity of its redox partner, cytochrome P4502B4 (cytP450). Here, we report the first structure of full-length rabbit ferric microsomal cytb5 (16 kDa), incorporated in two different membrane mimetics (detergent micelles and lipid bicelles). Differential line broadening of the cytb5 NMR resonances and site-directed mutagenesis data were used to characterize the cytb5 interaction epitope recognized by ferric microsomal cytP450 (56 kDa). Subsequently, a data-driven docking algorithm, HADDOCK (high ambiguity driven biomolecular docking), was used to generate the structure of the complex between cytP4502B4 and cytb5 using experimentally derived restraints from NMR, mutagenesis, and the double mutant cycle data obtained on the full-length proteins. Our docking and experimental results point to the formation of a dynamic electron transfer complex between the acidic convex surface of cytb5 and the concave basic proximal surface of cytP4502B4. The majority of the binding energy for the complex is provided by interactions between residues on the C-helix and β-bulge of cytP450 and residues at the end of helix α4 of cytb5. The structure of the complex allows us to propose an interprotein electron transfer pathway involving the highly conserved Arg-125 on cytP450 serving as a salt bridge between the heme propionates of cytP450 and cytb5. We have also shown that the addition of a substrate to cytP450 likely strengthens the cytb5-cytP450 interaction. This study paves the way to obtaining valuable structural, functional, and dynamic information on membrane-bound complexes.
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Affiliation(s)
- Shivani Ahuja
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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16
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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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17
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Contrasting factors on the kinetic path to protein complex formation diminish the effects of crowding agents. Biophys J 2013; 103:1011-9. [PMID: 23009850 DOI: 10.1016/j.bpj.2012.08.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/29/2012] [Accepted: 08/02/2012] [Indexed: 01/30/2023] Open
Abstract
The crowded environment of cells poses a challenge for rapid protein-protein association. Yet, it has been established that the rates of association are similar in crowded and in dilute solutions. Here we probe the pathway leading to fast association between TEM1 β-lactamase and its inhibitor protein BLIP in crowded solutions. We show that the affinity of the encounter complex, the rate of final complex formation, and the structure of the transition state are similar in crowded solutions and in buffer. The experimental results were reproduced by calculations based on the transient-complex theory for protein association. Both experiments and calculations suggest that while crowding agents decrease the diffusion constant of the associating proteins, they also induce an effective excluded-volume attraction between them. The combination of the two opposing effects thus results in nearly identical overall association rates in diluted and crowded solutions.
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18
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Kastritis PL, Bonvin AMJJ. On the binding affinity of macromolecular interactions: daring to ask why proteins interact. J R Soc Interface 2012; 10:20120835. [PMID: 23235262 PMCID: PMC3565702 DOI: 10.1098/rsif.2012.0835] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Interactions between proteins are orchestrated in a precise and time-dependent manner, underlying cellular function. The binding affinity, defined as the strength of these interactions, is translated into physico-chemical terms in the dissociation constant (Kd), the latter being an experimental measure that determines whether an interaction will be formed in solution or not. Predicting binding affinity from structural models has been a matter of active research for more than 40 years because of its fundamental role in drug development. However, all available approaches are incapable of predicting the binding affinity of protein–protein complexes from coordinates alone. Here, we examine both theoretical and experimental limitations that complicate the derivation of structure–affinity relationships. Most work so far has concentrated on binary interactions. Systems of increased complexity are far from being understood. The main physico-chemical measure that relates to binding affinity is the buried surface area, but it does not hold for flexible complexes. For the latter, there must be a significant entropic contribution that will have to be approximated in the future. We foresee that any theoretical modelling of these interactions will have to follow an integrative approach considering the biology, chemistry and physics that underlie protein–protein recognition.
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Affiliation(s)
- Panagiotis L Kastritis
- Bijvoet Center for Biomolecular Research, Faculty of Science, Chemistry, Utrecht University, , Padualaan 8, Utrecht, The Netherlands
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19
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Moal IH, Fernández-Recio J. SKEMPI: a Structural Kinetic and Energetic database of Mutant Protein Interactions and its use in empirical models. ACTA ACUST UNITED AC 2012; 28:2600-7. [PMID: 22859501 DOI: 10.1093/bioinformatics/bts489] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
MOTIVATION Empirical models for the prediction of how changes in sequence alter protein-protein binding kinetics and thermodynamics can garner insights into many aspects of molecular biology. However, such models require empirical training data and proper validation before they can be widely applied. Previous databases contained few stabilizing mutations and no discussion of their inherent biases or how this impacts model construction or validation. RESULTS We present SKEMPI, a database of 3047 binding free energy changes upon mutation assembled from the scientific literature, for protein-protein heterodimeric complexes with experimentally determined structures. This represents over four times more data than previously collected. Changes in 713 association and dissociation rates and 127 enthalpies and entropies were also recorded. The existence of biases towards specific mutations, residues, interfaces, proteins and protein families is discussed in the context of how the data can be used to construct predictive models. Finally, a cross-validation scheme is presented which is capable of estimating the efficacy of derived models on future data in which these biases are not present. AVAILABILITY The database is available online at http://life.bsc.es/pid/mutation_database/.
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Affiliation(s)
- Iain H Moal
- Joint BSC-IRB Research Program in Computational Biology, Life Science Department, Barcelona Supercomputing Center, Barcelona, Spain
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20
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Brown NG, Chow DC, Sankaran B, Zwart P, Prasad BVV, Palzkill T. Analysis of the binding forces driving the tight interactions between beta-lactamase inhibitory protein-II (BLIP-II) and class A beta-lactamases. J Biol Chem 2011; 286:32723-35. [PMID: 21775426 PMCID: PMC3173220 DOI: 10.1074/jbc.m111.265058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/25/2011] [Indexed: 12/19/2022] Open
Abstract
β-Lactamases hydrolyze β-lactam antibiotics to provide drug resistance to bacteria. β-Lactamase inhibitory protein-II (BLIP-II) is a potent proteinaceous inhibitor that exhibits low picomolar affinity for class A β-lactamases. This study examines the driving forces for binding between BLIP-II and β-lactamases using a combination of presteady state kinetics, isothermal titration calorimetry, and x-ray crystallography. The measured dissociation rate constants for BLIP-II and various β-lactamases ranged from 10(-4) to 10(-7) s(-1) and are comparable with those found in some of the tightest known protein-protein interactions. The crystal structures of BLIP-II alone and in complex with Bacillus anthracis Bla1 β-lactamase revealed no significant side-chain movement in BLIP-II in the complex versus the monomer. The structural rigidity of BLIP-II minimizes the loss of the entropy upon complex formation and, as indicated by thermodynamics experiments, may be a key determinant of the observed potent inhibition of β-lactamases.
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Affiliation(s)
- Nicholas G. Brown
- From the Departments of Pharmacology
- Biochemistry and Molecular Biology, and
| | | | - Banumathi Sankaran
- The Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Peter Zwart
- The Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - B. V. Venkataram Prasad
- Biochemistry and Molecular Biology, and
- Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030 and
| | - Timothy Palzkill
- From the Departments of Pharmacology
- Biochemistry and Molecular Biology, and
- Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030 and
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21
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Marquer C, Fruchart-Gaillard C, Letellier G, Marcon E, Mourier G, Zinn-Justin S, Ménez A, Servent D, Gilquin B. Structural model of ligand-G protein-coupled receptor (GPCR) complex based on experimental double mutant cycle data: MT7 snake toxin bound to dimeric hM1 muscarinic receptor. J Biol Chem 2011; 286:31661-75. [PMID: 21685390 DOI: 10.1074/jbc.m111.261404] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The snake toxin MT7 is a potent and specific allosteric modulator of the human M1 muscarinic receptor (hM1). We previously characterized by mutagenesis experiments the functional determinants of the MT7-hM1 receptor interaction (Fruchart-Gaillard, C., Mourier, G., Marquer, C., Stura, E., Birdsall, N. J., and Servent, D. (2008) Mol. Pharmacol. 74, 1554-1563) and more recently collected evidence indicating that MT7 may bind to a dimeric form of hM1 (Marquer, C., Fruchart-Gaillard, C., Mourier, G., Grandjean, O., Girard, E., le Maire, M., Brown, S., and Servent, D. (2010) Biol. Cell 102, 409-420). To structurally characterize the MT7-hM1 complex, we adopted a strategy combining double mutant cycle experiments and molecular modeling calculations. First, thirty-three ligand-receptor proximities were identified from the analysis of sixty-one double mutant binding affinities. Several toxin residues that are more than 25 Å apart still contact the same residues on the receptor. As a consequence, attempts to satisfy all the restraints by docking the toxin onto a single receptor failed. The toxin was then positioned onto two receptors during five independent flexible docking simulations. The different possible ligand and receptor extracellular loop conformations were described by performing simulations in explicit solvent. All the docking calculations converged to the same conformation of the MT7-hM1 dimer complex, satisfying the experimental restraints and in which (i) the toxin interacts with the extracellular side of the receptor, (ii) the tips of MT7 loops II and III contact one hM1 protomer, whereas the tip of loop I binds to the other protomer, and (iii) the hM1 dimeric interface involves the transmembrane helices TM6 and TM7. These results structurally support the high affinity and selectivity of the MT7-hM1 interaction and highlight the atypical mode of interaction of this allosteric ligand on its G protein-coupled receptor target.
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Affiliation(s)
- Catherine Marquer
- Laboratoire de Biologie Structurale et Radiobiologie, Service de Bioénergétique, Biologie Structurale et Mécanismes (SB2SM), CNRS Unité de Recherche Associée 2096, Gif sur Yvette F-91191, France
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22
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Hanes MS, Reynolds KA, McNamara C, Ghosh P, Bonomo RA, Kirsch JF, Handel TM. Specificity and cooperativity at β-lactamase position 104 in TEM-1/BLIP and SHV-1/BLIP interactions. Proteins 2011; 79:1267-76. [PMID: 21294157 PMCID: PMC3417816 DOI: 10.1002/prot.22961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 11/30/2010] [Accepted: 12/02/2010] [Indexed: 01/07/2023]
Abstract
Establishing a quantitative understanding of the determinants of affinity in protein-protein interactions remains challenging. For example, TEM-1/β-lactamase inhibitor protein (BLIP) and SHV-1/BLIP are homologous β-lactamase/β-lactamase inhibitor protein complexes with disparate K(d) values (3 nM and 2 μM, respectively), and a single substitution, D104E in SHV-1, results in a 1000-fold enhancement in binding affinity. In TEM-1, E104 participates in a salt bridge with BLIP K74, whereas the corresponding SHV-1 D104 does not in the wild type SHV-1/BLIP co-structure. Here, we present a 1.6 Å crystal structure of the SHV-1 D104E/BLIP complex that demonstrates that this point mutation restores this salt bridge. Additionally, mutation of a neighboring residue, BLIP E73M, results in salt bridge formation between SHV-1 D104 and BLIP K74 and a 400-fold increase in binding affinity. To understand how this salt bridge contributes to complex affinity, the cooperativity between the E/K or D/K salt bridge pair and a neighboring hot spot residue (BLIP F142) was investigated using double mutant cycle analyses in the background of the E73M mutation. We find that BLIP F142 cooperatively stabilizes both interactions, illustrating how a single mutation at a hot spot position can drive large perturbations in interface stability and specificity through a cooperative interaction network.
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Affiliation(s)
- Melinda S. Hanes
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94729,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093
| | - Kimberly A. Reynolds
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA 94729,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093
| | - Case McNamara
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA 92093
| | - Partho Ghosh
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA 92093
| | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, 44106,Department of Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, 44106
| | - Jack F. Kirsch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94729
| | - Tracy M. Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093
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23
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Busby B, Oashi T, Willis CD, Ackermann MA, Kontrogianni-Konstantopoulos A, Mackerell AD, Bloch RJ. Electrostatic interactions mediate binding of obscurin to small ankyrin 1: biochemical and molecular modeling studies. J Mol Biol 2011; 408:321-34. [PMID: 21333652 DOI: 10.1016/j.jmb.2011.01.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/25/2011] [Accepted: 01/28/2011] [Indexed: 10/18/2022]
Abstract
Small ankyrin 1 (sAnk1; also known as Ank1.5) is an integral protein of the sarcoplasmic reticulum (SR) in skeletal and cardiac muscle cells, where it is thought to bind to the C-terminal region of obscurin, a large modular protein that surrounds the contractile apparatus. Using fusion proteins in vitro, in combination with site-directed mutagenesis and surface plasmon resonance measurements, we previously showed that the binding site on sAnk1 for obscurin consists, in part, of six lysine and arginine residues. Here we show that four charged residues in the high-affinity binding site on obscurin for sAnk1 (between residues 6316 and 6345), consisting of three glutamates and a lysine, are necessary, but not sufficient, for this site on obscurin to bind to sAnk1 with high affinity. We also identify specific complementary mutations in sAnk1 that can partially or completely compensate for the changes in binding caused by charge-switching mutations in obscurin. We used molecular modeling to develop structural models of residues 6322-6339 of obscurin bound to sAnk1. The models, based on a combination of Brownian and molecular dynamics simulations, predict that the binding site on sAnk1 for obscurin is organized as two ankyrin-like repeats, with the last α-helical segment oriented at an angle to nearby helices, allowing lysine 6338 of obscurin to form an ionic interaction with aspartate 111 of sAnk1. This prediction was validated by double-mutant cycle experiments. Our results are consistent with a model in which electrostatic interactions between specific pairs of side chains on obscurin and sAnk1 promote binding and complex formation.
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Affiliation(s)
- Ben Busby
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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24
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Shifting the equilibrium between the encounter state and the specific form of a protein complex by interfacial point mutations. J Am Chem Soc 2010; 132:11487-95. [PMID: 20672804 DOI: 10.1021/ja100867c] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent experimental studies have confirmed a long-held view that protein complex formation proceeds via a short-lived encounter state. The population of this transient intermediate, stabilized mainly by long-range electrostatic interactions, varies among different complexes. Here we show that the occupancy of the encounter state can be modulated across a broad range by single point mutations of interfacial residues. Using a combination of Monte Carlo simulations and paramagnetic relaxation enhancement NMR spectroscopy, we illustrate that it is possible to both enhance and diminish the binding specificity in an electron transfer complex of yeast cytochrome c (Cc) and cytochrome c peroxidase. The Cc T12A mutation decreases the population of the encounter to 10% as compared with 30% in the wild-type complex. More dramatically, the Cc R13A substitution reverses the relative occupancies of the stereospecific and the encounter forms, with the latter now being the dominant species with the population of 80%. This finding indicates that the encounter state can make a large contribution to the stability of a protein complex. Also, it appears that by adjusting the amount of the encounter through a judicious choice of point mutations, we can remodel the energy landscape of a protein complex and tune its binding specificity.
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25
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Pierce BG, Haidar JN, Yu Y, Weng Z. Combinations of affinity-enhancing mutations in a T cell receptor reveal highly nonadditive effects within and between complementarity determining regions and chains. Biochemistry 2010; 49:7050-9. [PMID: 20681514 DOI: 10.1021/bi901969a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Understanding the energetic and structural response to multiple mutations in a protein-protein interface is a key aspect of rational protein design. Here we investigate the cooperativity of combinations of point mutations of a T cell receptor (TCR) that binds in vivo to HLA-A2 MHC and a viral peptide. The mutations were obtained from two sources: a structure-based design study on the TCR alpha chain (nine mutations) and an in vitro selection study on the TCR beta chain (four mutations). In addition to combining the highest-affinity variants from each chain, we tested other combinations of mutations within and among the chains, for a total of 23 TCR mutants that we measured for binding kinetics to the peptide and major histocompatibility complex. A wide range of binding affinities was observed, from 2- to 1000-fold binding improvement versus that of the wild type, with significant nonadditive effects observed within and between TCR chains. This included an amino acid-dependent cooperative interaction between CDR1 and CDR3 residues that are separated by more than 9 A in the wild-type complex. When analyzing the kinetics of the mutations, we found that the association rates were primarily responsible for the cooperativity, while the dissociation rates were responsible for the anticooperativity (less-than-additive energetics). On the basis of structural modeling of anticooperative mutants, we determined that side chain clash between proximal mutants likely led to nonadditive binding energies. These results highlight the complex nature of TCR association and binding and will be informative in future design efforts that combine multiple mutant residues.
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Affiliation(s)
- Brian G Pierce
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, USA
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26
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Schreiber G, Haran G, Zhou HX. Fundamental aspects of protein-protein association kinetics. Chem Rev 2010; 109:839-60. [PMID: 19196002 DOI: 10.1021/cr800373w] [Citation(s) in RCA: 559] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- G Schreiber
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel.
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27
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Fawzi NL, Doucleff M, Suh JY, Clore GM. Mechanistic details of a protein-protein association pathway revealed by paramagnetic relaxation enhancement titration measurements. Proc Natl Acad Sci U S A 2010; 107:1379-84. [PMID: 20080627 PMCID: PMC2824347 DOI: 10.1073/pnas.0909370107] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein-protein association generally proceeds via the intermediary of a transient, lowly populated, encounter complex ensemble. The mechanism whereby the interacting molecules in this ensemble locate their final stereospecific structure is poorly understood. Further, a fundamental question is whether the encounter complex ensemble is an effectively homogeneous population of nonspecific complexes or whether it comprises a set of distinct structural and thermodynamic states. Here we use intermolecular paramagnetic relaxation enhancement (PRE), a technique that is exquisitely sensitive to lowly populated states in the fast exchange regime, to characterize the mechanistic details of the transient encounter complex interactions between the N-terminal domain of Enzyme I (EIN) and the histidine-containing phosphocarrier protein (HPr), two major bacterial signaling proteins. Experiments were conducted at an ionic strength of 150 mM NaCl to eliminate any spurious nonspecific associations not relevant under physiological conditions. By monitoring the dependence of the intermolecular transverse PRE (Gamma(2)) rates measured on (15)N-labeled EIN on the concentration of paramagnetically labeled HPr, two distinct types of encounter complex configurations along the association pathway are identified and dissected. The first class, which is in equilibrium with and sterically occluded by the specific complex, probably involves rigid body rotations and small translations near or at the active site. In contrast, the second class of encounter complex configurations can coexist with the specific complex to form a ternary complex ensemble, which may help EIN compete with other HPr binding partners in vivo by increasing the effective local concentration of HPr even when the active site of EIN is occupied.
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Affiliation(s)
- Nicolas L. Fawzi
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Michaeleen Doucleff
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Jeong-Yong Suh
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
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28
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Gochin M, Cai L. The role of amphiphilicity and negative charge in glycoprotein 41 interactions in the hydrophobic pocket. J Med Chem 2009; 52:4338-44. [PMID: 19534533 DOI: 10.1021/jm900190q] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydrophobic pocket within the coiled coil domain of HIV-1 gp41 is considered to be a hot-spot suitable for small molecule intervention of fusion, although so far it has yielded only microM inhibitors. Previous peptide studies have identified specific hydrophobic interactions and a Lys-Asp salt bridge as contributing to binding affinity in the pocket. Negative charge appears to be critical for activity of small molecules. We have examined the role of charge and amphiphilic character in the interaction by studying a series of short pocket binding peptides differing in charge, helical content, and in the presence or absence of the Lys-Asp salt bridge, and a series of fatty acid salts with varying charge and hydrocarbon length. Quantitative binding analysis revealed that long-range electrostatic forces and a greasy nonspecific hydrophobic interaction were sufficient for microM potency. The results suggest that an extended interaction site may be necessary for higher potency. We examined a region of the coiled coil immediately C-terminal to the pocket and found that specific salt bridge and hydrogen bond networks may reside in this region. Negatively charged groups extended toward or beyond the C-terminus of the pocket could therefore result in improved low molecular weight fusion inhibitors.
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Affiliation(s)
- Miriam Gochin
- Department of Basic Sciences, Touro University-California, Vallejo, California 94592, USA.
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Harel M, Spaar A, Schreiber G. Fruitful and futile encounters along the association reaction between proteins. Biophys J 2009; 96:4237-48. [PMID: 19450494 DOI: 10.1016/j.bpj.2009.02.054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 02/02/2009] [Accepted: 02/20/2009] [Indexed: 10/20/2022] Open
Abstract
The association reaction between pairs of proteins proceeds through an encounter complex that develops into the final complex. Here, we combined Brownian dynamics simulations with experimental studies to analyze the structures of the encounter complexes along the association reaction between TEM1-beta-lactamase and its inhibitor, beta-lactamase-inhibitor protein. The encounter complex can be considered as an ensemble of short-lived low free-energy states that are stabilized primarily by electrostatic forces and desolvation. For the wild-type, the simulation showed two main encounter regions located outside the physical binding site. One of these regions was located near the experimentally determined transition state. To validate whether these encounters are fruitful or futile, we examined three groups of mutations that altered the encounter. The first group consisted of mutations that increased the experimental rate of association through electrostatic optimization. This resulted in an increase in the size of the encounter region located near the experimentally determined transition state, as well as a decrease in the energy of this region and an increase in the number of successful trajectories (i.e., encounters that develop into complex). A second group of mutations was specifically designed to either increase or decrease the size and energy of the second encounter complex, but either way it did not affect k(on). A third group of mutations consisted of residues that increased k(on) without significantly affecting the encounter complexes. These results indicate that the size and energy of the encounter regions are only two of several parameters that lead to fruitful association, and that electrostatic optimization is a major driving force in fast association.
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Affiliation(s)
- Michal Harel
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
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Insights into Positive and Negative Requirements for Protein–Protein Interactions by Crystallographic Analysis of the β-Lactamase Inhibitory Proteins BLIP, BLIP-I, and BLP. J Mol Biol 2009; 389:289-305. [DOI: 10.1016/j.jmb.2009.03.058] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 03/15/2009] [Accepted: 03/20/2009] [Indexed: 11/24/2022]
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The courtship of proteins: Understanding the encounter complex. FEBS Lett 2009; 583:1060-6. [DOI: 10.1016/j.febslet.2009.02.046] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 02/25/2009] [Accepted: 02/27/2009] [Indexed: 11/15/2022]
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Principal determinants leading to transition state formation of a protein-protein complex, orientation trumps side-chain interactions. Proc Natl Acad Sci U S A 2009; 106:2559-64. [PMID: 19196954 DOI: 10.1073/pnas.0809800106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The binding transition state (TS) is the rate-limiting step for transient molecular interactions. This important step in the molecular recognition process, however, is largely understood only at a qualitative level. To establish a more quantitative picture of the TS structure, we exploit a set of biophysical techniques that have provided major insights in protein folding applications. As a model system representing the large class of "weakly charged" protein-protein interactions, we examine the binding of a variety of human growth hormone (hGH) variants to the human growth hormone receptor (hGHR) and the human prolactin receptor (hPRLR). hGH variants were chosen to probe different features of the TS structure, based on their highly reengineered interfaces. Both Eyring and urea (m value) analyses suggest that the majority of binding surface burial occurs after TS. A comprehensive phi analysis showed that individual hGH interface residues do not contribute energetically to the stability of the TS, but there is a TS "hot spot" in the receptor. Zinc dependence studies that take advantage of an endogenous tetracoordinated interfacial metal binding demonstrate that surfaces of the molecules have attained a high orientational complementarity by the time the TS is reached. The model that best fits these data are that a "knobs-into-holes" process precisely aligns the two molecular interfaces in forming the TS structure. Surprisingly, most of the thermodynamic character of the binding reaction is focused in the fine-tuning process occurring after TS.
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Volkov AN, Bashir Q, Worrall JAR, Ubbink M. Binding hot spot in the weak protein complex of physiological redox partners yeast cytochrome C and cytochrome C peroxidase. J Mol Biol 2008; 385:1003-13. [PMID: 19026661 DOI: 10.1016/j.jmb.2008.10.091] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 10/16/2008] [Accepted: 10/30/2008] [Indexed: 10/21/2022]
Abstract
Transient protein interactions mediate many vital cellular processes such as signal transduction or intermolecular electron transfer. However, due to difficulties associated with their structural characterization, little is known about the principles governing recognition and binding in weak transient protein complexes. In particular, it has not been well established whether binding hot spots, which are frequently found in strong static complexes, also govern transient protein interactions. To address this issue, we have investigated an electron transfer complex of physiological partners from yeast: yeast iso-1-cytochrome c (Cc) and yeast cytochrome c peroxidase (CcP). Using isothermal titration calorimetry and NMR spectroscopy, we show that Cc R13 is a hot-spot residue, as R13A mutation has a strong destabilizing effect on binding. Furthermore, we employ a double-mutant cycle to illustrate that Cc R13 interacts with CcP Y39. The present results, in combination with those of earlier mutational studies, have enabled us to outline the extent of the energetically important Cc-CcP binding region. Based on our analysis, we propose that binding energy hot spots, which are prevalent in static protein complexes, could also govern transient protein interactions.
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Affiliation(s)
- Alexander N Volkov
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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Sarewicz M, Borek A, Daldal F, Froncisz W, Osyczka A. Demonstration of short-lived complexes of cytochrome c with cytochrome bc1 by EPR spectroscopy: implications for the mechanism of interprotein electron transfer. J Biol Chem 2008; 283:24826-36. [PMID: 18617515 PMCID: PMC2529009 DOI: 10.1074/jbc.m802174200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 07/08/2008] [Indexed: 11/18/2022] Open
Abstract
One of the steps of a common pathway for biological energy conversion involves electron transfer between cytochrome c and cytochrome bc1. To clarify the mechanism of this reaction, we examined the structural association of those two proteins using the electron transfer-independent electron paramagnetic resonance (EPR) techniques. Drawing on the differences in the continuous wave EPR spectra and saturation recoveries of spin-labeled bacterial and mitochondrial cytochromes c recorded in the absence and presence of bacterial cytochrome bc1, we have exposed a time scale of dynamic equilibrium between the bound and the free state of cytochrome c at various ionic strengths. Our data show a successive decrease of the bound cytochrome c fraction as the ionic strength increases, with a limit of approximately 120 mm NaCl above which essentially no bound cytochrome c can be detected by EPR. This limit does not apply to all of the interactions of cytochrome c with cytochrome bc1 because the cytochrome bc1 enzymatic activity remained high over a much wider range of ionic strengths. We concluded that EPR monitors just the tightly bound state of the association and that an averaged lifetime of this state decreases from over 100 micros at low ionic strength to less than 400 ns at an ionic strength above 120 mm. This suggests that at physiological ionic strength, the tightly bound complex on average lasts less than the time needed for a single electron exchange between hemes c and c1, indicating that productive electron transfer requires several collisions of the two molecules. This is consistent with an early idea of diffusion-coupled reactions that link the soluble electron carriers with the membranous complexes, which, we believe, provides a robust means of regulating electron flow through these complexes.
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Affiliation(s)
- Marcin Sarewicz
- Department of Biophysics, Faculty of
Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387
Kraków, Poland and the Department of
Biology, Plant Science Institute, University of Pennsylvania, Philadelphia,
Pennsylvania 19104
| | - Arkadiusz Borek
- Department of Biophysics, Faculty of
Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387
Kraków, Poland and the Department of
Biology, Plant Science Institute, University of Pennsylvania, Philadelphia,
Pennsylvania 19104
| | - Fevzi Daldal
- Department of Biophysics, Faculty of
Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387
Kraków, Poland and the Department of
Biology, Plant Science Institute, University of Pennsylvania, Philadelphia,
Pennsylvania 19104
| | - Wojciech Froncisz
- Department of Biophysics, Faculty of
Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387
Kraków, Poland and the Department of
Biology, Plant Science Institute, University of Pennsylvania, Philadelphia,
Pennsylvania 19104
| | - Artur Osyczka
- Department of Biophysics, Faculty of
Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387
Kraków, Poland and the Department of
Biology, Plant Science Institute, University of Pennsylvania, Philadelphia,
Pennsylvania 19104
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