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Baskaran K, Ploskon E, Tejero R, Yokochi M, Harrus D, Liang Y, Peisach E, Persikova I, Ramelot TA, Sekharan M, Tolchard J, Westbrook JD, Bardiaux B, Schwieters CD, Patwardhan A, Velankar S, Burley SK, Kurisu G, Hoch JC, Montelione GT, Vuister GW, Young JY. Restraint validation of biomolecular structures determined by NMR in the Protein Data Bank. Structure 2024; 32:824-837.e1. [PMID: 38490206 PMCID: PMC11162339 DOI: 10.1016/j.str.2024.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 01/13/2024] [Accepted: 02/19/2024] [Indexed: 03/17/2024]
Abstract
Biomolecular structure analysis from experimental NMR studies generally relies on restraints derived from a combination of experimental and knowledge-based data. A challenge for the structural biology community has been a lack of standards for representing these restraints, preventing the establishment of uniform methods of model-vs-data structure validation against restraints and limiting interoperability between restraint-based structure modeling programs. The NEF and NMR-STAR formats provide a standardized approach for representing commonly used NMR restraints. Using these restraint formats, a standardized validation system for assessing structural models of biopolymers against restraints has been developed and implemented in the wwPDB OneDep data deposition-validation-biocuration system. The resulting wwPDB restraint violation report provides a model vs. data assessment of biomolecule structures determined using distance and dihedral restraints, with extensions to other restraint types currently being implemented. These tools are useful for assessing NMR models, as well as for assessing biomolecular structure predictions based on distance restraints.
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Affiliation(s)
- Kumaran Baskaran
- Biological Magnetic Resonance Data Bank, Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA.
| | - Eliza Ploskon
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Roberto Tejero
- Departamento de Quίmica Fίsica, Universidad de Valencia, Dr. Moliner, 50 46100 Burjassot, Valencia, Spain
| | - Masashi Yokochi
- Protein Data Bank Japan, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; Protein Data Bank Japan, Protein Research Foundation, Minoh, Osaka 562-8686, Japan
| | - Deborah Harrus
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Yuhe Liang
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ezra Peisach
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Irina Persikova
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Theresa A Ramelot
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Monica Sekharan
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - James Tolchard
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - John D Westbrook
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Benjamin Bardiaux
- Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR3528, 75015 Paris, France
| | - Charles D Schwieters
- Computational Biomolecular Magnetic Resonance Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ardan Patwardhan
- The Electron Microscopy Data Bank, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Sameer Velankar
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Stephen K Burley
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Research Collaboratory for Structural Bioinformatics Protein Data Bank, San Diego Supercomputer Center, University of California, La Jolla, La Jolla, CA, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Genji Kurisu
- Protein Data Bank Japan, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan; Protein Data Bank Japan, Protein Research Foundation, Minoh, Osaka 562-8686, Japan
| | - Jeffrey C Hoch
- Biological Magnetic Resonance Data Bank, Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA
| | - Gaetano T Montelione
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA.
| | - Geerten W Vuister
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, UK.
| | - Jasmine Y Young
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
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2
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Baskaran K, Ploskon E, Tejero R, Yokochi M, Harrus D, Liang Y, Peisach E, Persikova I, Ramelot TA, Sekharan M, Tolchard J, Westbrook JD, Bardiaux B, Schwieters CD, Patwardhan A, Velankar S, Burley SK, Kurisu G, Hoch JC, Montelione GT, Vuister GW, Young JY. Restraint Validation of Biomolecular Structures Determined by NMR in the Protein Data Bank. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575520. [PMID: 38328042 PMCID: PMC10849500 DOI: 10.1101/2024.01.15.575520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Biomolecular structure analysis from experimental NMR studies generally relies on restraints derived from a combination of experimental and knowledge-based data. A challenge for the structural biology community has been a lack of standards for representing these restraints, preventing the establishment of uniform methods of model-vs-data structure validation against restraints and limiting interoperability between restraint-based structure modeling programs. The NMR exchange (NEF) and NMR-STAR formats provide a standardized approach for representing commonly used NMR restraints. Using these restraint formats, a standardized validation system for assessing structural models of biopolymers against restraints has been developed and implemented in the wwPDB OneDep data deposition-validation-biocuration system. The resulting wwPDB Restraint Violation Report provides a model vs. data assessment of biomolecule structures determined using distance and dihedral restraints, with extensions to other restraint types currently being implemented. These tools are useful for assessing NMR models, as well as for assessing biomolecular structure predictions based on distance restraints.
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Affiliation(s)
- Kumaran Baskaran
- Biological Magnetic Resonance Data Bank, Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA
| | - Eliza Ploskon
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Roberto Tejero
- Departamento de Quίmica Fίsica, Universidad de Valencia, Dr. Moliner, 50 46100-Burjassot, Valencia, Spain
| | - Masashi Yokochi
- Protein Data Bank Japan, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
- Protein Data Bank Japan, Protein Research Foundation, Minoh, Osaka 562-8686, Japan
| | - Deborah Harrus
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Yuhe Liang
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ezra Peisach
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Irina Persikova
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Theresa A Ramelot
- Dept of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, 12180 USA
| | - Monica Sekharan
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - James Tolchard
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - John D Westbrook
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Benjamin Bardiaux
- Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR3528, 75015 Paris, France
| | - Charles D Schwieters
- Computational Biomolecular Magnetic Resonance Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ardan Patwardhan
- The Electron Microscopy Data Bank, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Sameer Velankar
- Protein Data Bank in Europe, EMBL-EBI, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, United Kingdom
| | - Stephen K Burley
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, San Diego Supercomputer Center, University of California, La Jolla, California, USA
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Genji Kurisu
- Protein Data Bank Japan, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
- Protein Data Bank Japan, Protein Research Foundation, Minoh, Osaka 562-8686, Japan
| | - Jeffrey C Hoch
- Biological Magnetic Resonance Data Bank, Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA
| | - Gaetano T Montelione
- Dept of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, 12180 USA
- Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Geerten W Vuister
- Department of Molecular and Cell Biology, Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Jasmine Y Young
- Research Collaboratory for Structural Bioinformatics Protein Data Bank, Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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De Sanctis S, Malloni WM, Kremer W, Tomé AM, Lang EW, Neidig KP, Kalbitzer HR. Singular spectrum analysis for an automated solvent artifact removal and baseline correction of 1D NMR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 210:177-83. [PMID: 21459640 DOI: 10.1016/j.jmr.2011.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 02/27/2011] [Accepted: 03/01/2011] [Indexed: 05/16/2023]
Abstract
NMR spectroscopy in biology and medicine is generally performed in aqueous solutions, thus in (1)H NMR spectroscopy, the dominant signal often stems from the partly suppressed solvent and can be many orders of magnitude larger than the resonances of interest. Strong solvent signals lead to a disappearance of weak resonances of interest close to the solvent artifact and to base plane variations all over the spectrum. The AUREMOL-SSA/ALS approach for automated solvent artifact removal and baseline correction has been originally developed for multi-dimensional NMR spectroscopy. Here, we describe the necessary adaptations for an automated application to one-dimensional NMR spectra. Its core algorithm is still based on singular spectrum analysis (SSA) applied on time domain signals (FIDs) and it is still combined with an automated baseline correction (ALS) in the frequency domain. However, both steps (SSA and ALS) have been modified in order to achieve optimal results when dealing with one-dimensional spectra. The performance of the method has been tested on one-dimensional synthetic and experimental spectra including the back-calculated spectrum of HPr protein and an experimental spectrum of a human urine sample. The latter has been recorded with the typically used NOESY-type 1D pulse sequence including water pre-saturation. Furthermore, the fully automated AUREMOL-SSA/ALS procedure includes the managing of oversampled, digitally filtered and zero-filled data and the correction of the frequency domain phase shift caused by the group delay time shift from the digital finite response filtering.
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Affiliation(s)
- Silvia De Sanctis
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
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4
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Malloni WM, De Sanctis S, Tomé AM, Lang EW, Munte CE, Neidig KP, Kalbitzer HR. Automated solvent artifact removal and base plane correction of multidimensional NMR protein spectra by AUREMOL-SSA. JOURNAL OF BIOMOLECULAR NMR 2010; 47:101-111. [PMID: 20414700 DOI: 10.1007/s10858-010-9414-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 03/22/2010] [Indexed: 05/29/2023]
Abstract
Strong solvent signals lead to a disappearance of weak protein signals close to the solvent resonance frequency and to base plane variations all over the spectrum. AUREMOL-SSA provides an automated approach for solvent artifact removal from multidimensional NMR protein spectra. Its core algorithm is based on singular spectrum analysis (SSA) in the time domain and is combined with an automated base plane correction in the frequency domain. The performance of the method has been tested on synthetic and experimental spectra including two-dimensional NOESY and TOCSY spectra and a three-dimensional (1)H,(13)C-HCCH-TOCSY spectrum. It can also be applied to frequency domain spectra since an optional inverse Fourier transformation is included in the algorithm.
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Affiliation(s)
- Wilhelm M Malloni
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040, Regensburg, Germany
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Abstract
The main drawback of protein NMR spectroscopy today is still the extensive amount of time required for solving a single structure. The main bottleneck in this respect is the manual evaluation of the experimental spectra. A clear solution to this challenge is the development of automated methods for this purpose. At the current stage of development, this goal has been almost or in a few cases fully reached for favorable cases such as well-behaved, stably folding smaller proteins below the 25 kDa range. For larger and/or more difficult molecules, the input of a human expert is still required. However, even here, automated routines will substantially speed up the structure determination process. In this report, we will summarize recent developments in this field and especially emphasize practical aspects important for a successful automated protein structure determination in solution. An important aspect closely related to structure determination is structure validation. Therefore, we devote a section to automated approaches for this topic.
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Affiliation(s)
- Wolfram Gronwald
- Institute for Biophysics and Physical Biochemistry, University of Regensburg, Regensburg, Germany
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6
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Baskaran K, Kirchhöfer R, Huber F, Trenner J, Brunner K, Gronwald W, Neidig KP, Kalbitzer HR. Chemical shift optimization in multidimensional NMR spectra by AUREMOL-SHIFTOPT. JOURNAL OF BIOMOLECULAR NMR 2009; 43:197-210. [PMID: 19234673 DOI: 10.1007/s10858-009-9304-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 12/18/2008] [Indexed: 05/27/2023]
Abstract
A problem often encountered in multidimensional NMR-spectroscopy is that an existing chemical shift list of a protein has to be used to assign an experimental spectrum but does not fit sufficiently well for a safe assignment. A similar problem occurs when temperature or pressure series of n-dimensional spectra are to be evaluated automatically. We have developed two different algorithms, AUREMOL-SHIFTOPT1 and AUREMOL-SHIFTOPT2 that fulfill this task. In the present contribution their performance is analyzed employing a set of simulated and experimental two-dimensional and three-dimensional spectra obtained from three different proteins. A new z-score based on atom and amino acid specific chemical shift distributions is introduced to weight the chemical shift contributions in different dimensions properly.
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Affiliation(s)
- Kumaran Baskaran
- Department of Biophysics and Physical Biochemistry, University of Regensburg, Postfach, 93040, Regensburg, Federal Republic of Germany
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Gronwald W, Hohm T, Hoffmann D. Evolutionary Pareto-optimization of stably folding peptides. BMC Bioinformatics 2008; 9:109. [PMID: 18284690 PMCID: PMC2263021 DOI: 10.1186/1471-2105-9-109] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 02/19/2008] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND As a rule, peptides are more flexible and unstructured than proteins with their substantial stabilizing hydrophobic cores. Nevertheless, a few stably folding peptides have been discovered. This raises the question whether there may be more such peptides that are unknown as yet. These molecules could be helpful in basic research and medicine. RESULTS As a method to explore the space of conformationally stable peptides, we have developed an evolutionary algorithm that allows optimization of sequences with respect to several criteria simultaneously, for instance stability, accessibility of arbitrary parts of the peptide, etc. In a proof-of-concept experiment we have perturbed the sequence of the peptide Villin Headpiece, known to be stable in vitro. Starting from the perturbed sequence we applied our algorithm to optimize peptide stability and accessibility of a loop. Unexpectedly, two clusters of sequences were generated in this way that, according to our criteria, should form structures with higher stability than the wild-type. The structures in one of the clusters possess a fold that markedly differs from the native fold of Villin Headpiece. One of the mutants predicted to be stable was selected for synthesis, its molecular 3D-structure was characterized by nuclear magnetic resonance spectroscopy, and its stability was measured by circular dichroism. Predicted structure and stability were in good agreement with experiment. Eight other sequences and structures, including five with a non-native fold are provided as bona fide predictions. CONCLUSION The results suggest that much more conformationally stable peptides may exist than are known so far, and that small fold classes could comprise well-separated sub-folds.
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Affiliation(s)
- Wolfram Gronwald
- Institute for Functional Genomics, University of Regensburg, Josef-Engert-Strasse 9, 93053 Regensburg, Germany.
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Gronwald W, Brunner K, Kirchhöfer R, Trenner J, Neidig KP, Kalbitzer HR. AUREMOL-RFAC-3D, combination of R-factors and their use for automated quality assessment of protein solution structures. JOURNAL OF BIOMOLECULAR NMR 2007; 37:15-30. [PMID: 17136423 DOI: 10.1007/s10858-006-9096-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 09/20/2006] [Indexed: 05/12/2023]
Abstract
We present here the computer program AUREMOL-RFAC-3D that is a generalization of the previously published program RFAC for the fully automated estimation of residual indices (R-factors) from 2D NOESY spectra. It is part of the larger AUREMOL software package (www.auremol.de). RFAC-3D calculates R-factors directly from two-dimensional homonuclear NOESY spectra as well as from three-dimensional (15)N or (13)C edited NOESY-HSQC spectra and thus extends the application range to larger proteins. The fully automated method includes automated peak picking and integration, a Bayesian noise and artifact recognition and the use of the complete relaxation matrix formalism. To enhance the reliability of the calculated R-factors the method is also generalized to calculate combined R-factors from a set of 2D and 3D-spectra. For an optimal combination of the information derived from different sources a plausible formalism had to be derived. In addition, we present a novel direct R-factors based measure that correlates an R-factors as defined in this paper to the root mean square deviation of the actual structure from the optimal structure. The new program has been successfully tested on the histidine containing phosphocarrier protein (HPr) from Staphylococcus carnosus and on the Ras-binding domain (RBD) of the Ral guanine-nucleotide dissociation stimulation factor (RalGDS).
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Affiliation(s)
- Wolfram Gronwald
- Department of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstr.31, D-93040, Regensburg, Federal Republic of Germany
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Sivakolundu SG, Bashford D, Kriwacki RW. Disordered p27Kip1 exhibits intrinsic structure resembling the Cdk2/cyclin A-bound conformation. J Mol Biol 2005; 353:1118-28. [PMID: 16214166 DOI: 10.1016/j.jmb.2005.08.074] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 08/25/2005] [Accepted: 08/29/2005] [Indexed: 10/25/2022]
Abstract
p27Kip1 (p27) influences cell division by regulating nuclear cyclin-dependent kinases. Before binding, p27 is at least partially disordered and folds upon binding its Cdk/cyclin targets. 30-40% of human proteins, including p27, are predicted to contain disordered segments, and have been termed intrinsically unstructured proteins (IUPs). Unfortunately, the inherent dynamics of IUPs hamper detailed analysis of their structure/function relationships. Here, we describe the use of molecular dynamics (MD) computations and solution NMR spectroscopy to reveal that several segments of the p27 kinase inhibitory domain (p27-KID), in addition to the previously characterized helical segment, exist as highly populated, intrinsically folded structural units (IFSUs). Several IFSUs resemble structural features of bound p27-KID, while another exhibits alternative conformations. Interestingly, the highly conserved, specificity determining segment of p27 is shown to be highly disordered. Elucidation of IFSUs within p27-KID allows consideration of their influences on the thermodynamics and kinetics of Cdk/cyclin binding. The degree to which IFSUs are populated within p27-KID is surprising and suggests that other putative IUPs contain IFSUs that may be studied using similar techniques.
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Affiliation(s)
- Sivashankar G Sivakolundu
- Department of Structural Biology, St. Jude Children's Research Hospital, 332 North Lauderdale St., Memphis, TN 38105, USA
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Hattori M, Li H, Yamada H, Akasaka K, Hengstenberg W, Gronwald W, Kalbitzer HR. Infrequent cavity-forming fluctuations in HPr from Staphylococcus carnosus revealed by pressure- and temperature-dependent tyrosine ring flips. Protein Sci 2005; 13:3104-14. [PMID: 15557257 PMCID: PMC2287304 DOI: 10.1110/ps.04877104] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Infrequent structural fluctuations of a globular protein is seldom detected and studied in detail. One tyrosine ring of HPr from Staphylococcus carnosus, an 88-residue phosphocarrier protein with no disulfide bonds, undergoes a very slow ring flip, the pressure and temperature dependence of which is studied in detail using the on-line cell high-pressure nuclear magnetic resonance technique in the pressure range from 3 MPa to 200 MPa and in the temperature range from 257 K to 313 K. The ring of Tyr6 is buried sandwiched between a beta-sheet and alpha-helices (the water-accessible area is less than 0.26 nm2), its hydroxyl proton being involved in an internal hydrogen bond. The ring flip rates 10(1)-10(5) s(-1) were determined from the line shape analysis of H(delta1, delta2) and H(epsilon1,epsilon2) of Tyr6, giving an activation volume DeltaV++ of 0.044 +/- 0.008 nm3 (27 mL mol(-1)), an activation enthalpy DeltaH++ of 89 +/- 10 kJ mol(-1), and an activation entropy DeltaS++ of 16 +/- 2 JK(-1) mol(-1). The DeltaV++) and DeltaH++ values for HPr found previously for Tyr and Phe ring flips of BPTI and cytochrome c fall within the range of DeltaV(double dagger) of 28 to 51 mL mol(-1) and DeltaH++ of 71 to 155 kJ mol(-1). The fairly common DeltaV++ and DeltaH++ values are considered to represent the extra space or cavity required for the ring flip and the extra energy required to create a cavity, respectively, in the core part of a globular protein. Nearly complete cold denaturation was found to take place at 200 MPa and 257 K independently from the ring reorientation process.
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Affiliation(s)
- Mineyuki Hattori
- Department of Molecular Science, Graduate School of Science and Technology, Kobe University, Japan
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