1
|
Wapeesittipan P, Mey ASJS, Walkinshaw MD, Michel J. Allosteric effects in cyclophilin mutants may be explained by changes in nano-microsecond time scale motions. Commun Chem 2019. [DOI: 10.1038/s42004-019-0136-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
2
|
van Gunsteren WF, Daura X, Hansen N, Mark AE, Oostenbrink C, Riniker S, Smith LJ. Validation of Molecular Simulation: An Overview of Issues. Angew Chem Int Ed Engl 2017; 57:884-902. [PMID: 28682472 DOI: 10.1002/anie.201702945] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Indexed: 12/14/2022]
Abstract
Computer simulation of molecular systems enables structure-energy-function relationships of molecular processes to be described at the sub-atomic, atomic, supra-atomic, or supra-molecular level. To interpret results of such simulations appropriately, the quality of the calculated properties must be evaluated. This depends on the way the simulations are performed and on the way they are validated by comparison to values Qexp of experimentally observable quantities Q. One must consider 1) the accuracy of Qexp , 2) the accuracy of the function Q(rN ) used to calculate a Q-value based on a molecular configuration rN of N particles, 3) the sensitivity of the function Q(rN ) to the configuration rN , 4) the relative time scales of the simulation and experiment, 5) the degree to which the calculated and experimental properties are equivalent, and 6) the degree to which the system simulated matches the experimental conditions. Experimental data is limited in scope and generally corresponds to averages over both time and space. A critical analysis of the various factors influencing the apparent degree of (dis)agreement between simulations and experiment is presented and illustrated using examples from the literature. What can be done to enhance the validation of molecular simulation is also discussed.
Collapse
Affiliation(s)
- Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine, Universitat Autonoma de Barcelona, UAB, 08193, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies, ICREA, 08010, Barcelona, Spain
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, 70569, Stuttgart, Germany
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Sereina Riniker
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Lorna J Smith
- Department of Chemistry, Inorganic Chemistry, Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| |
Collapse
|
3
|
van Gunsteren WF, Daura X, Hansen N, Mark AE, Oostenbrink C, Riniker S, Smith LJ. Validierung von molekularen Simulationen: eine Übersicht verschiedener Aspekte. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Wilfred F. van Gunsteren
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine; Universitat Autònoma de Barcelona; Spanien
- Catalan Institution for Research and Advanced Studies, ICREA; Barcelona Spanien
| | - Niels Hansen
- Institut für Technische Thermodynamik und Thermische Verfahrenstechnik; Universität Stuttgart; Deutschland
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences; University of Queensland; St. Lucia Australien
| | - Chris Oostenbrink
- Institut für Molekulare Modellierung und Simulation; Universität für Bodenkultur Wien; Österreich
| | - Sereina Riniker
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Lorna J. Smith
- Inorganic Chemistry Laboratory; Department of Chemistry; University of Oxford; Großbritannien
| |
Collapse
|
4
|
Initiation of prolyl cis-trans isomerisation in the CDR-H3 loop of an antibody in response to antigen binding. Sci Rep 2017; 7:16964. [PMID: 29208911 PMCID: PMC5717248 DOI: 10.1038/s41598-017-16766-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/16/2017] [Indexed: 01/12/2023] Open
Abstract
Proline cis-trans isomerisation is a regulatory mechanism used in a range of biological processes, and is related to various diseases such as Alzheimers disease and cancer. However, the details of the exact molecular mechanism by which it occurs are not known. Using X-ray crystallography, proline isomerisation has been shown to occur following formation of an antigen-antibody complex between the target epiregulin (EPR) and the antibody 9E5, at proline (Pro103), located in the third complementarity-determining region (CDR) of the heavy chain of 9E5. To obtain an accurate description of the pathway involved in cis-trans isomerisation in this system, we performed ten independent long molecular dynamics (MD) simulations starting at a stable transient bound structure obtained from many short binding MD simulations. As a result, we were able to describe the process by which cis-trans isomerisation is initiated, and suggest a catalysis mechanism for cis-trans isomerization in this antigen-antibody system. We found that Asp102, which is immediately adjacent to Pro103, rotates while changing its interacting partner residues in the light chain of 9E5, and at the same time EPR polar residues help to stabilise the intermediate states in the isomerisation process by interacting strongly with Asp102.
Collapse
|
5
|
Smith LJ, Athill R, van Gunsteren WF, Hansen N. Interpretation of Seemingly Contradictory Data: Low NMR S 2 Order Parameters Observed in Helices and High NMR S 2 Order Parameters in Disordered Loops of the Protein hGH at Low pH. Chemistry 2017; 23:9585-9591. [PMID: 28503764 DOI: 10.1002/chem.201700896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Indexed: 12/16/2022]
Abstract
At low pH, human growth hormone (hGH) adopts a partially folded state, in which the native helices are maintained, but the long loop regions and side-chain packing become disordered. Some of the S2 order parameters for backbone N-H vectors derived from NMR relaxation measurements on hGH at low pH initially seem contradictory. Three isolated residues (15, 20, and 171) in helices A and D exhibit low order parameter values (<0.5) indicating flexibility, whereas residue 143 in the centre of a long flexible loop region has a high order parameter (0.82). Using S2 order parameter restraining MD simulations, this paradox has been resolved. Low S2 values in helices are due to the presence of a mixture of 310 -helical and α-helical hydrogen bonds. High S2 values in relatively disordered parts of a protein may be due to fluctuating networks of hydrogen bonds between the backbone and the side chains, which restrict the motion of N-H bond vectors.
Collapse
Affiliation(s)
- Lorna J Smith
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
| | - Roya Athill
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
| | | | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, 70569, Stuttgart, Germany
| |
Collapse
|
6
|
van Gunsteren WF, Allison JR, Daura X, Dolenc J, Hansen N, Mark AE, Oostenbrink C, Rusu VH, Smith LJ. Bestimmung von Strukturinformation aus experimentellen Messdaten für Biomoleküle. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601828] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Wilfred F. van Gunsteren
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Jane R. Allison
- Centre for Theor. Chem. and Phys. & Institute of Natural and Mathematical Sciences; Massey Univ.; Auckland Neuseeland
- Biomolecular Interaction Centre; University of Canterbury, Christchurch; Neuseeland
- Maurice Wilkins Centre for Molecular Biodiscovery; Neuseeland
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine; Universitat Autònoma de Barcelona (UAB); 08193 Barcelona Spanien
- Catalan Institution for Research and Advanced Studies (ICREA); 08010 Barcelona Spanien
| | - Jožica Dolenc
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Niels Hansen
- Institut für Technische Thermodynamik und Thermische Verfahrenstechnik; Universität Stuttgart; Pfaffenwaldring 9 70569 Stuttgart Deutschland
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences; University of Queensland; St. Lucia QLD 4072 Australien
| | - Chris Oostenbrink
- Institut für Molekulare Modellierung und Simulation; Universität für Bodenkultur Wien; Wien Österreich
| | - Victor H. Rusu
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Lorna J. Smith
- Department of Chemistry; University of Oxford, Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR Großbritannien
| |
Collapse
|
7
|
van Gunsteren WF, Allison JR, Daura X, Dolenc J, Hansen N, Mark AE, Oostenbrink C, Rusu VH, Smith LJ. Deriving Structural Information from Experimentally Measured Data on Biomolecules. Angew Chem Int Ed Engl 2016; 55:15990-16010. [PMID: 27862777 DOI: 10.1002/anie.201601828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/08/2016] [Indexed: 12/27/2022]
Abstract
During the past half century, the number and accuracy of experimental techniques that can deliver values of observables for biomolecular systems have been steadily increasing. The conversion of a measured value Qexp of an observable quantity Q into structural information is, however, a task beset with theoretical and practical problems: 1) insufficient or inaccurate values of Qexp , 2) inaccuracies in the function Q(r→) used to relate the quantity Q to structure r→ , 3) how to account for the averaging inherent in the measurement of Qexp , 4) how to handle the possible multiple-valuedness of the inverse r→(Q) of the function Q(r→) , to mention a few. These apply to a variety of observable quantities Q and measurement techniques such as X-ray and neutron diffraction, small-angle and wide-angle X-ray scattering, free-electron laser imaging, cryo-electron microscopy, nuclear magnetic resonance, electron paramagnetic resonance, infrared and Raman spectroscopy, circular dichroism, Förster resonance energy transfer, atomic force microscopy and ion-mobility mass spectrometry. The process of deriving structural information from measured data is reviewed with an eye to non-experts and newcomers in the field using examples from the literature of the effect of the various choices and approximations involved in the process. A list of choices to be avoided is provided.
Collapse
Affiliation(s)
- Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Jane R Allison
- Centre for Theor. Chem. and Phys. & Institute of Natural and Mathematical Sciences, Massey Univ., Auckland, New Zealand.,Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona (UAB), 08193, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain
| | - Jožica Dolenc
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, 70569, Stuttgart, Germany
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Victor H Rusu
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Lorna J Smith
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
| |
Collapse
|
8
|
Ladani ST, Souffrant MG, Barman A, Hamelberg D. Computational perspective and evaluation of plausible catalytic mechanisms of peptidyl-prolyl cis-trans isomerases. Biochim Biophys Acta Gen Subj 2015; 1850:1994-2004. [PMID: 25585011 DOI: 10.1016/j.bbagen.2014.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/23/2014] [Accepted: 12/29/2014] [Indexed: 01/16/2023]
Abstract
BACKGROUND Peptidyl prolyl cis-trans isomerization of the protein backbone is involved in the regulation of many biological processes. Cis-trans isomerization is notoriously slow and is catalyzed by a family of cis-trans peptidyl prolyl isomerases (PPIases) that have been implicated in many diseases. A general consensus on how these enzymes speed up prolyl isomerization has not been reached after decades of both experimental and computational studies. SCOPE OF REVIEW Computational studies carried out to understand the catalytic mechanism of the prototypical FK506 binding protein 12, Cyclophilin A and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) are reviewed. A summary and an evaluation of the implications of the proposed mechanisms from computational studies are presented. MAJOR CONCLUSIONS The analysis of computational studies and evaluation of the proposed mechanisms provide a general consensus and a better understanding of PPIase catalysis. The speedup of the rate of peptidyl-prolyl isomerization by PPIases can be best described by a catalytic mechanism in which the substrate in transition state configuration is stabilized. The enzymes preferentially bind the transition state configuration of the substrate relative to the cis conformation, which in most cases is bound better than the trans conformation of the substrate. Stabilization of the transition state configuration of the substrate leads to a lower free energy barrier and a faster rate of isomerization when compared to the uncatalyzed isomerization reaction. GENERAL SIGNIFICANCE Fully understanding the catalytic mechanism of PPIases has broad implications for drug design, elucidation of the molecular basis of many diseases, protein engineering, and enzyme catalysis in general. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
Collapse
Affiliation(s)
- Safieh Tork Ladani
- Department of Chemistry and the Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-3965, USA
| | - Michael G Souffrant
- Department of Chemistry and the Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-3965, USA
| | - Arghya Barman
- Department of Chemistry and the Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-3965, USA
| | - Donald Hamelberg
- Department of Chemistry and the Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302-3965, USA.
| |
Collapse
|
9
|
Cyclophilin A catalyzes proline isomerization by an electrostatic handle mechanism. Proc Natl Acad Sci U S A 2014; 111:10203-8. [PMID: 24982184 DOI: 10.1073/pnas.1404220111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Proline isomerization is a ubiquitous process that plays a key role in the folding of proteins and in the regulation of their functions. Different families of enzymes, known as "peptidyl-prolyl isomerases" (PPIases), catalyze this reaction, which involves the interconversion between the cis and trans isomers of the N-terminal amide bond of the amino acid proline. However, complete descriptions of the mechanisms by which these enzymes function have remained elusive. We show here that cyclophilin A, one of the most common PPIases, provides a catalytic environment that acts on the substrate through an electrostatic handle mechanism. In this mechanism, the electrostatic field in the catalytic site turns the electric dipole associated with the carbonyl group of the amino acid preceding the proline in the substrate, thus causing the rotation of the peptide bond between the two residues. We identified this mechanism using a combination of NMR measurements, molecular dynamics simulations, and density functional theory calculations to simultaneously determine the cis-bound and trans-bound conformations of cyclophilin A and its substrate as the enzymatic reaction takes place. We anticipate that this approach will be helpful in elucidating whether the electrostatic handle mechanism that we describe here is common to other PPIases and, more generally, in characterizing other enzymatic processes.
Collapse
|
10
|
Abstract
![]()
The Crk adaptor proteins play a central
role as a molecular timer
for the formation of protein complexes including various growth and
differentiation factors. The loss of regulation of Crk results in
many kinds of cancers. A self-regulatory mechanism for Crk was recently
proposed, which involves domain–domain rearrangement. It is
initiated by a cis–trans isomerization of a specific proline
residue (Pro238 in chicken Crk II) and can be accelerated by Cyclophilin
A. To understand how the proline switch controls the autoinhibition
at the molecular level, we performed large-scale molecular dynamics
and metadynamics simulations in the context of short peptides and
multidomain constructs of chicken Crk II. We found that the equilibrium
and kinetic properties of the macrostates are regulated not only by
the local environments of specified prolines but also by the global
organization of multiple domains. We observe the two macrostates (cis
closed/autoinhibited and trans open/uninhibited) consistent with NMR
experiments and predict barriers. We also propose an intermediate
state, the trans closed state, which interestingly was reported to
be a prevalent state in human Crk II. The existence of this macrostate
suggests that the rate of switching off the autoinhibition by Cyp
A may be limited by the relaxation rate of this intermediate state.
Collapse
Affiliation(s)
- Junchao Xia
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey , 610 Taylor Road, Piscataway, New Jersey 08854, United States
| | | |
Collapse
|
11
|
McGowan LC, Hamelberg D. Conformational plasticity of an enzyme during catalysis: intricate coupling between cyclophilin A dynamics and substrate turnover. Biophys J 2013; 104:216-26. [PMID: 23332074 DOI: 10.1016/j.bpj.2012.11.3815] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/25/2012] [Accepted: 11/27/2012] [Indexed: 01/15/2023] Open
Abstract
Enzyme catalysis is central to almost all biochemical processes, speeding up rates of reactions to biological relevant timescales. Enzymes make use of a large ensemble of conformations in recognizing their substrates and stabilizing the transition states, due to the inherent dynamical nature of biomolecules. The exact role of these diverse enzyme conformations and the interplay between enzyme conformational dynamics and catalysis is, according to the literature, not well understood. Here, we use molecular dynamics simulations to study human cyclophilin A (CypA), in order to understand the role of enzyme motions in the catalytic mechanism and recognition. Cyclophilin A is a tractable model system to study using classical simulation methods, because catalysis does not involve bond formation or breakage. We show that the conformational dynamics of active site residues of substrate-bound CypA is inherent in the substrate-free enzyme. CypA interacts with its substrate via conformational selection as the configurations of the substrate changes during catalysis. We also show that, in addition to tight intermolecular hydrophobic interactions between CypA and the substrate, an intricate enzyme-substrate intermolecular hydrogen-bonding network is extremely sensitive to the configuration of the substrate. These enzyme-substrate intermolecular interactions are loosely formed when the substrate is in the reactant and product states and become well formed and reluctant to break when the substrate is in the transition state. Our results clearly suggest coupling among enzyme-substrate intermolecular interactions, the dynamics of the enzyme, and the chemical step. This study provides further insights into the mechanism of peptidyl-prolyl cis/trans isomerases and the general interplay between enzyme conformational dynamics and catalysis.
Collapse
Affiliation(s)
- Lauren C McGowan
- Department of Chemistry and the Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia, USA
| | | |
Collapse
|
12
|
Ladani ST, Hamelberg D. Entropic and Surprisingly Small Intramolecular Polarization Effects in the Mechanism of Cyclophilin A. J Phys Chem B 2012; 116:10771-8. [DOI: 10.1021/jp305917c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Safieh Tork Ladani
- Department of Chemistry and Center
for Biotechnology
and Drug Design, Georgia State University, Atlanta, Georgia 30302-4098, United States
| | - Donald Hamelberg
- Department of Chemistry and Center
for Biotechnology
and Drug Design, Georgia State University, Atlanta, Georgia 30302-4098, United States
| |
Collapse
|
13
|
Zhang C, Lai L. Automatch: Target-binding protein design and enzyme design by automatic pinpointing potential active sites in available protein scaffolds. Proteins 2012; 80:1078-94. [DOI: 10.1002/prot.24009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 11/17/2011] [Accepted: 11/18/2011] [Indexed: 11/10/2022]
|
14
|
Fogolari F, Corazza A, Varini N, Rotter M, Gumral D, Codutti L, Rennella E, Viglino P, Bellotti V, Esposito G. Molecular dynamics simulation of β₂-microglobulin in denaturing and stabilizing conditions. Proteins 2010; 79:986-1001. [PMID: 21287627 DOI: 10.1002/prot.22940] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 10/22/2010] [Accepted: 11/02/2010] [Indexed: 11/11/2022]
Abstract
β₂-Microglobulin has been a model system for the study of fibril formation for 20 years. The experimental study of β₂-microglobulin structure, dynamics, and thermodynamics in solution, at atomic detail, along the pathway leading to fibril formation is difficult because the onset of disorder and aggregation prevents signal resolution in Nuclear Magnetic Resonance experiments. Moreover, it is difficult to characterize conformers in exchange equilibrium. To gain insight (at atomic level) on processes for which experimental information is available at molecular or supramolecular level, molecular dynamics simulations have been widely used in the last decade. Here, we use molecular dynamics to address three key aspects of β₂-microglobulin, which are known to be relevant to amyloid formation: (1) 60 ns molecular dynamics simulations of β₂-microglobulin in trifluoroethanol and in conditions mimicking low pH are used to study the behavior of the protein in environmental conditions that are able to trigger amyloid formation; (2) adaptive biasing force molecular dynamics simulation is used to force cis-trans isomerization at Proline 32 and to calculate the relative free energy in the folded and unfolded state. The native-like trans-conformer (known as intermediate 2 and determining the slow phase of refolding), is simulated for 10 ns, detailing the possible link between cis-trans isomerization and conformational disorder; (3) molecular dynamics simulation of highly concentrated doxycycline (a molecule able to suppress fibril formation) in the presence of β₂-microglobulin provides details of the binding modes of the drug and a rationale for its effect.
Collapse
Affiliation(s)
- Federico Fogolari
- Dipartimento di Scienze e Tecnologie Biomediche, Universita' di Udine, Piazzale Kolbe 4, 33100 Udine, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Namanja AT, Wang XJ, Xu B, Mercedes-Camacho AY, Wilson BD, Wilson KA, Etzkorn FA, Peng JW. Toward flexibility-activity relationships by NMR spectroscopy: dynamics of Pin1 ligands. J Am Chem Soc 2010; 132:5607-9. [PMID: 20356313 PMCID: PMC3056322 DOI: 10.1021/ja9096779] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Drug design involves iterative ligand modifications. For flexible ligands, these modifications often entail restricting conformational flexibility. However, defining optimal restriction strategies can be challenging if the relationship between ligand flexibility and biological activity is unclear. Here, we describe an approach for ligand flexibility-activity studies using Nuclear Magnetic Resonance (NMR) spin relaxation. Specifically, we use (13)C relaxation dispersion measurements to compare site-specific changes in ligand flexibility for a series of related ligands that bind a common macromolecular receptor. The flexibility changes reflect conformational reorganization resulting from formation of the receptor-ligand complex. We demonstrate this approach on three structurally similar but flexibly differentiated ligands of human Pin1, a peptidyl-prolyl isomerase. The approach is able to map the ligand dynamics relevant for activity and expose changes in those dynamics caused by conformational locking. Thus, NMR flexibility-activity studies can provide information to guide strategic ligand rigidification. As such, they help establish an experimental basis for developing flexibility-activity relationships (FAR) to complement traditional structure-activity relationships (SAR) in molecular design.
Collapse
Affiliation(s)
- Andrew T. Namanja
- University of Notre Dame, Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| | - Xiaodong J. Wang
- Virginia Tech, Department of Chemistry, Blacksburg, Virginia 24061
| | - Bailing Xu
- Virginia Tech, Department of Chemistry, Blacksburg, Virginia 24061
| | | | - Brian D. Wilson
- University of Notre Dame, Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| | - Kimberly A. Wilson
- University of Notre Dame, Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| | | | - Jeffrey W. Peng
- University of Notre Dame, Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| |
Collapse
|
16
|
Musselman C, Zhang Q, Al-Hashimi H, Andricioaei I. Referencing strategy for the direct comparison of nuclear magnetic resonance and molecular dynamics motional parameters in RNA. J Phys Chem B 2010; 114:929-39. [PMID: 20039757 PMCID: PMC4287414 DOI: 10.1021/jp905286h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations are both techniques that can be used to characterize the structural dynamics of biomolecules and their underlying time scales. Comparison of relaxation parameters obtained through each methodology allows for cross validation of techniques and for complementarity in the analysis of dynamics. Here we present a combined NMR/MD study of the dynamics of HIV-1 transactivation response (TAR) RNA. We compute relaxation constants (R(1), R(2), and NOE) and model-free parameters (S(2) and tau) from a 65 ns molecular dynamics (MD) trajectory and compare them with the respective parameters measured in a domain-elongation NMR experiment. Using the elongated domain as the frame of reference for all computed parameters allows for a direct comparison between experiment and simulation. We see good agreement for many parameters and gain further insight into the nature of the local and global dynamics of TAR, which are found to be quite complex, spanning multiple time scales. For the few cases where agreement is poor, comparison of the dynamical parameters provides insight into the limits of each technique. We suggest a frequency-matching procedure that yields an upper bound for the time scale of dynamics to which the NMR relaxation experiment is sensitive.
Collapse
Affiliation(s)
- Catherine Musselman
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | | |
Collapse
|
17
|
Fraser JS, Clarkson MW, Degnan SC, Erion R, Kern D, Alber T. Hidden alternative structures of proline isomerase essential for catalysis. Nature 2009; 462:669-73. [PMID: 19956261 PMCID: PMC2805857 DOI: 10.1038/nature08615] [Citation(s) in RCA: 388] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 10/26/2009] [Indexed: 11/09/2022]
Abstract
A long-standing challenge is to understand at the atomic level how protein dynamics contribute to enzyme catalysis. X-ray crystallography can provide snapshots of conformational substates sampled during enzymatic reactions, while NMR relaxation methods reveal the rates of interconversion between substates and the corresponding relative populations. However, these current methods cannot simultaneously reveal the detailed atomic structures of the rare states and rationalize the finding that intrinsic motions in the free enzyme occur on a timescale similar to the catalytic turnover rate. Here we introduce dual strategies of ambient-temperature X-ray crystallographic data collection and automated electron-density sampling to structurally unravel interconverting substates of the human proline isomerase, cyclophilin A (CYPA, also known as PPIA). A conservative mutation outside the active site was designed to stabilize features of the previously hidden minor conformation. This mutation not only inverts the equilibrium between the substates, but also causes large, parallel reductions in the conformational interconversion rates and the catalytic rate. These studies introduce crystallographic approaches to define functional minor protein conformations and, in combination with NMR analysis of the enzyme dynamics in solution, show how collective motions directly contribute to the catalytic power of an enzyme.
Collapse
Affiliation(s)
- James S Fraser
- Department of Molecular and Cell Biology/QB3, University of California, Berkeley, California 94720-3220, USA
| | | | | | | | | | | |
Collapse
|
18
|
Moparthi SB, Hammarström P, Carlsson U. A nonessential role for Arg 55 in cyclophilin18 for catalysis of proline isomerization during protein folding. Protein Sci 2009; 18:475-9. [PMID: 19185003 DOI: 10.1002/pro.28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The protein folding process is often in vitro rate-limited by slow cis-trans proline isomerization steps. Importantly, the rate of this process in vivo is accelerated by prolyl isomerases (PPIases). The archetypal PPIase is the human cyclophilin 18 (Cyp18 or CypA), and Arg 55 has been demonstrated to play a crucial role when studying short peptide substrates in the catalytic action of Cyp18 by stabilizing the transition state of isomerization. However, in this study we show that a R55A mutant of Cyp18 is as efficient as the wild type to accelerate the refolding reaction of human carbonic anhydrase II (HCA II). Thus, it is evident that the active-site located Arg 55 is not required for catalysis of the rate-limiting prolyl cis-trans isomerization steps during the folding of a protein substrate as HCA II. Nevertheless, catalysis of cis-trans proline isomerization in HCA II occurs in the active-site of Cyp18, since binding of the inhibitor cyclosporin A abolishes rate acceleration of the refolding reaction. Obviously, the catalytic mechanisms of Cyp18 can differ when acting upon a simple model peptide, four residues long, with easily accessible Pro residues compared with a large protein molecule undergoing folding with partly or completely buried Pro residues. In the latter case, the isomerization kinetics are significantly slower and simpler mechanistic factors such as desolvation and/or strain might operate during folding-assisted catalysis, since binding to the hydrophobic active site is still a prerequisite for catalysis.
Collapse
|
19
|
Hamelberg D, McCammon JA. Mechanistic insight into the role of transition-state stabilization in cyclophilin A. J Am Chem Soc 2009; 131:147-52. [PMID: 19128175 PMCID: PMC2651649 DOI: 10.1021/ja806146g] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidyl prolyl cis-trans isomerases (PPIases) are ubiquitous enzymes in biology that catalyze the cis-trans isomerization of the proline imide peptide bond in many cell signaling pathways. The local change of the isomeric state of the prolyl peptide bond acts as a switching mechanism in altering the conformation of proteins. A complete understanding of the mechanism of PPIases is still lacking, and current experimental techniques have not been able to provide a detailed atomistic picture. Here we have carried out several accelerated molecular dynamics simulations with explicit solvent, and we have provided a detailed description of cis-trans isomerization of the free and cyclophilin A-catalyzed process. We show that the catalytic mechanism of cyclophilin is due mainly to the stabilization and preferential binding of the transition state that is achieved by a favorable hydrogen bond interaction with a backbone NH group. We also show that the substrate in the transition state interacts more favorably with the enzyme than the cis isomer, which in turn interacts more favorably than the trans isomer. The stability of the enzyme-substrate complex is directly correlated with the interaction the substrate makes with a highly conserved arginine residue. Finally, we show that catalysis is achieved through the rotation of the carbonyl oxygen on the N-terminal of the prolyl peptide bond in a predominately unidirectional fashion.
Collapse
Affiliation(s)
- Donald Hamelberg
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-4098, USA
| | | |
Collapse
|
20
|
Mechanism of action of cyclophilin a explored by metadynamics simulations. PLoS Comput Biol 2009; 5:e1000309. [PMID: 19282959 PMCID: PMC2643488 DOI: 10.1371/journal.pcbi.1000309] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/28/2009] [Indexed: 11/22/2022] Open
Abstract
Trans/cis prolyl isomerisation is involved in several biological processes, including the development of numerous diseases. In the HIV-1 capsid protein (CA), such a process takes place in the uncoating and recruitment of the virion and is catalyzed by cyclophilin A (CypA). Here, we use metadynamics simulations to investigate the isomerization of CA's model substrate HAGPIA in water and in its target protein CypA. Our results allow us to propose a novel mechanistic hypothesis, which is finally consistent with all of the available molecular biology data. Peptidyl prolyl isomerases are ubiquitous enzymes whose actions are crucial in several biological processes, such as, for instance, in cellular signalling and in the onset of several diseases, e.g., HIV infection. Therefore, these isomerases are promising targets for the design of new drugs. For this purpose, we need to understand their molecular mechanism of action. One of the most characterized peptidyl prolyl isomerases is cyclophilin A. Previous studies characterized the roles of several protein regions in isomerase function. However, there are still experimentally identified important portions of the protein whose specific actions in the mechanism are still not known. Here, we address this problem by an extensive computational study of cyclophilin A and a substrate peptide that is part of the HIV-1 capside protein. We present a novel four-step mechanism of the whole enzymatic process, which is consistent with all of the available experimental data. Moreover, these steps can be used as targets for the development of drugs, e.g., for HIV-1 infection.
Collapse
|
21
|
Isaksson J, Nyström S, Derbyshire D, Wallberg H, Agback T, Kovacs H, Bertini I, Giachetti A, Luchinat C. Does a Fast Nuclear Magnetic Resonance Spectroscopy- and X-Ray Crystallography Hybrid Approach Provide Reliable Structural Information of Ligand-Protein Complexes? A Case Study of Metalloproteinases. J Med Chem 2009; 52:1712-22. [DOI: 10.1021/jm801388q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Johan Isaksson
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Susanne Nyström
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Dean Derbyshire
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Hans Wallberg
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Tatiana Agback
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Helena Kovacs
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Ivano Bertini
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Andrea Giachetti
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| | - Claudio Luchinat
- Medivir AB, PO Box 1086, SE-141 22 Huddinge, Sweden, Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland, Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy, Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy, Department of Agricultural Biotechnology, University of Florence, Via Maragliano 75−77, 50144 Florence, Italy, ProtEra S.r.l., Via delle Idee 22, 50019 Sesto Fiorentino,
| |
Collapse
|
22
|
Galat A. Functional drift of sequence attributes in the FK506-binding proteins (FKBPs). J Chem Inf Model 2008; 48:1118-30. [PMID: 18412331 DOI: 10.1021/ci700429n] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diverse members of the FK506-binding proteins (FKBPs) group and their complexes with different macrocyclic ligands of fungal origins such as FK506, rapamycin, ascomycin, and their immunosuppressive and nonimmunosuppressive derivatives display a variety of cellular and biological activities. The functional relatedness of the FKBPs was estimated from the following attributes of their aligned sequences: 1 degrees conservation of the consensus sequence; 2 degrees sequence similarity; 3 degrees pI; 4 degrees hydrophobicity; 5 degrees amino acid hydrophobicity and bulkiness profiles. Analyses of the multiple sequence alignments and intramolecular interaction networks calculated from a series of structures of the FKBPs revealed some variations in the interaction clusters formed by the AA residues that are crucial for sustaining peptidylprolyl cis/trans isomerases (PPIases) activity and binding capacity of the FKBPs. Fine diversification of the sequences of the multiple paralogues and orthologues of the FKBPs encoded in different genomes alter the intramolecular interaction patterns of their structures and allowed them to gain some selectivity in binding to diverse targets (functional drift).
Collapse
Affiliation(s)
- Andrzej Galat
- Institute de Biologie et de Technologies de Saclay, DSV/CEA, CE-Saclay, F-91191 Gif-sur-Yvette Cedex, France.
| |
Collapse
|
23
|
van Gunsteren WF, Dolenc J, Mark AE. Molecular simulation as an aid to experimentalists. Curr Opin Struct Biol 2008; 18:149-53. [PMID: 18280138 DOI: 10.1016/j.sbi.2007.12.007] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 12/19/2007] [Accepted: 12/21/2007] [Indexed: 11/26/2022]
Abstract
Computer-based molecular simulation techniques are increasingly used to interpret experimental data on biomolecular systems at an atomic level. Direct comparison between experiment and simulation is, however, seldom straightforward. The available experimental data are limited in scope and generally correspond to averages over both time and space. A critical analysis of the various factors that may influence the apparent degree of agreement between the results of simulations and experimentally measured quantities is presented and illustrated using examples from recent literature.
Collapse
Affiliation(s)
- Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, CH-8093 Zurich, Switzerland.
| | | | | |
Collapse
|
24
|
Abstract
Over the last 30 years, computation based on molecular models is playing an increasingly important role in biology, biological chemistry and biophysics. Since only a very limited number of properties of biomolecular systems are actually accessible to measurement by experimental means, computer simulation complements experiments by providing not only averages, but also distributions and time series of any definable, observable or non-observable, quantity. Biomolecular simulation may be used (i) to interpret experimental data, (ii) to provoke new experiments, (iii) to replace experiments and (iv) to protect intellectual property. Progress over the last 30 years is sketched and perspectives are outlined for the future.
Collapse
|
25
|
Abstract
Proline is unique in the realm of amino acids in its ability to adopt completely distinct cis and trans conformations, which allows it to act as a backbone switch that is controlled by prolyl cis-trans isomerization. This intrinsically slow interconversion can be catalyzed by the evolutionarily conserved group of peptidyl prolyl cis-trans isomerase enzymes. These enzymes include cyclophilins and FK506-binding proteins, which are well known for their isomerization-independent role as cellular targets for immunosuppressive drugs. The significance of enzyme-catalyzed prolyl cis-trans isomerization as an important regulatory mechanism in human physiology and pathology was not recognized until the discovery of the phosphorylation-specific prolyl isomerase Pin1. Recent studies indicate that both phosphorylation-dependent and phosphorylation-independent prolyl cis-trans isomerization can act as a novel molecular timer to help control the amplitude and duration of a cellular process, and prolyl cis-trans isomerization might be a new target for therapeutic interventions.
Collapse
Affiliation(s)
- Kun Ping Lu
- Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 77 Avenue Louis Pasteur, NRB 1030, Boston, Massachusetts 02215, USA.
| | | | | | | |
Collapse
|
26
|
Namanja AT, Peng T, Zintsmaster JS, Elson AC, Shakour MG, Peng JW. Substrate recognition reduces side-chain flexibility for conserved hydrophobic residues in human Pin1. Structure 2007; 15:313-27. [PMID: 17355867 DOI: 10.1016/j.str.2007.01.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 01/22/2007] [Accepted: 01/24/2007] [Indexed: 11/26/2022]
Abstract
Pin1 is a peptidyl-prolyl isomerase consisting of a WW domain and a catalytic isomerase (PPIase) domain connected by a flexible linker. Pin1 recognizes phospho-Ser/Thr-Pro motifs in cell-signaling proteins, and is both a cancer and an Alzheimer's disease target. Here, we provide novel insight into the functional motions underlying Pin1 substrate interaction using nuclear magnetic resonance deuterium ((2)D) and carbon ((13)C) spin relaxation. Specifically, we compare Pin1 side-chain motions in the presence and absence of a known phosphopeptide substrate derived from the mitotic phosphatase Cdc25. Substrate interaction alters Pin1 side-chain motions on both the microsecond-millisecond (mus-ms) and picosecond-nanosecond (ps-ns) timescales. Alterations include loss of ps-ns flexibility along an internal conduit of hydrophobic residues connecting the catalytic site with the interdomain interface. These residues are conserved among Pin1 homologs; hence, their dynamics are likely important for the Pin1 mechanism.
Collapse
Affiliation(s)
- Andrew T Namanja
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA
| | | | | | | | | | | |
Collapse
|