1
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Nishimura C, Kikuchi T. Non-Native Structures of Apomyoglobin and Apoleghemoglobin in Folding Intermediates Related to the Protein Misfolding. Molecules 2023; 28:molecules28093970. [PMID: 37175379 PMCID: PMC10179781 DOI: 10.3390/molecules28093970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
Protein folding is essential for a polypeptide chain to acquire its proper structure and function. Globins are a superfamily of ubiquitous heme-binding α-helical proteins whose function is principally to regulate oxygen homoeostasis. In this review, we explore the hierarchical helical formation in the globin proteins apomyoglobin and leghemoglobin, and we discuss the existence of non-native and misfolded structures occurring during the course of folding to its native state. This review summarizes the research aimed at characterizing and comparing the equilibrium and kinetic intermediates, as well as delineating the complete folding pathway at a molecular level, in order to answer the following questions: "What is the mechanism of misfolding via a folding intermediate? Does the non-native structure stabilize the contemporary intermediate structure? Does the non-native structure induce slower folding?" The role of the non-native structures in the folding intermediate related to misfolding is also discussed.
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Affiliation(s)
- Chiaki Nishimura
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Tokyo 164-8530, Japan
| | - Takeshi Kikuchi
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Kusatsu 528-8577, Japan
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2
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Kuwajima K, Yagi-Utsumi M, Yanaka S, Kato K. DMSO-Quenched H/D-Exchange 2D NMR Spectroscopy and Its Applications in Protein Science. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123748. [PMID: 35744871 PMCID: PMC9230524 DOI: 10.3390/molecules27123748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022]
Abstract
Hydrogen/deuterium (H/D) exchange combined with two-dimensional (2D) NMR spectroscopy has been widely used for studying the structure, stability, and dynamics of proteins. When we apply the H/D-exchange method to investigate non-native states of proteins such as equilibrium and kinetic folding intermediates, H/D-exchange quenching techniques are indispensable, because the exchange reaction is usually too fast to follow by 2D NMR. In this article, we will describe the dimethylsulfoxide (DMSO)-quenched H/D-exchange method and its applications in protein science. In this method, the H/D-exchange buffer is replaced by an aprotic DMSO solution, which quenches the exchange reaction. We have improved the DMSO-quenched method by using spin desalting columns, which are used for medium exchange from the H/D-exchange buffer to the DMSO solution. This improvement has allowed us to monitor the H/D exchange of proteins at a high concentration of salts or denaturants. We describe methodological details of the improved DMSO-quenched method and present a case study using the improved method on the H/D-exchange behavior of unfolded human ubiquitin in 6 M guanidinium chloride.
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Affiliation(s)
- Kunihiro Kuwajima
- Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Correspondence: (K.K.); (K.K.)
| | - Maho Yagi-Utsumi
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
| | - Saeko Yanaka
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
- Correspondence: (K.K.); (K.K.)
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3
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Aghera N, Udgaonkar JB. Stepwise Assembly of β-Sheet Structure during the Folding of an SH3 Domain Revealed by a Pulsed Hydrogen Exchange Mass Spectrometry Study. Biochemistry 2017; 56:3754-3769. [DOI: 10.1021/acs.biochem.7b00374] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nilesh Aghera
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B. Udgaonkar
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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4
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NISHIMURA C. Folding of apomyoglobin: Analysis of transient intermediate structure during refolding using quick hydrogen deuterium exchange and NMR. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:10-27. [PMID: 28077807 PMCID: PMC5406622 DOI: 10.2183/pjab.93.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/31/2016] [Indexed: 05/27/2023]
Abstract
The structures of apomyoglobin folding intermediates have been widely analyzed using physical chemistry methods including fluorescence, circular dichroism, small angle X-ray scattering, NMR, mass spectrometry, and rapid mixing. So far, at least two intermediates (on sub-millisecond- and millisecond-scales) have been demonstrated for apomyoglobin folding. The combination of pH-pulse labeling and NMR is a useful tool for analyzing the kinetic intermediates at the atomic level. Its use has revealed that the latter-phase kinetic intermediate of apomyoglobin (6 ms) was composed of helices A, B, G and H, whereas the equilibrium intermediate, called the pH 4 molten-globule intermediate, was composed mainly of helices A, G and H. The improved strategy for the analysis of the kinetic intermediate was developed to include (1) the dimethyl sulfoxide method, (2) data processing with the various labeling times, and (3) a new in-house mixer. Particularly, the rapid mixing revealed that helices A and G were significantly more protected at the earlier stage (400 µs) of the intermediate (former-phase intermediate) than the other helices. Mutation studies, where each hydrophobic residue was replaced with an alanine in helices A, B, E, F, G and H, indicated that both non-native and native-like structures exist in the latter-phase folding intermediate. The N-terminal part of helix B is a weak point in the intermediate, and the docking of helix E residues to the core of the A, B, G and H helices was interrupted by a premature helix B, resulting in the accumulation of the intermediate composed of helices A, B, G and H. The prediction-based protein engineering produced important mutants: Helix F in a P88K/A90L/S92K/A94L mutant folded in the latter-phase intermediate, although helix F in the wild type does not fold even at the native state. Furthermore, in the L11G/W14G/A70L/G73W mutant, helix A did not fold but helix E did, which is similar to what was observed in the kinetic intermediate of apoleghemoglobin. Thus, this protein engineering resulted in a changed structure for the apomyoglobin folding intermediate.
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Affiliation(s)
- Chiaki NISHIMURA
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Nakano-ku, Tokyo, Japan
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5
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Pancsa R, Varadi M, Tompa P, Vranken WF. Start2Fold: a database of hydrogen/deuterium exchange data on protein folding and stability. Nucleic Acids Res 2015; 44:D429-34. [PMID: 26582925 PMCID: PMC4702845 DOI: 10.1093/nar/gkv1185] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 10/24/2015] [Indexed: 01/02/2023] Open
Abstract
Proteins fulfil a wide range of tasks in cells; understanding how they fold into complex three-dimensional (3D) structures and how these structures remain stable while retaining sufficient dynamics for functionality is essential for the interpretation of overall protein behaviour. Since the 1950's, solvent exchange-based methods have been the most powerful experimental means to obtain information on the folding and stability of proteins. Considerable expertise and care were required to obtain the resulting datasets, which, despite their importance and intrinsic value, have never been collected, curated and classified. Start2Fold is an openly accessible database (http://start2fold.eu) of carefully curated hydrogen/deuterium exchange (HDX) data extracted from the literature that is open for new submissions from the community. The database entries contain (i) information on the proteins investigated and the underlying experimental procedures and (ii) the classification of the residues based on their exchange protection levels, also allowing for the instant visualization of the relevant residue groups on the 3D structures of the corresponding proteins. By providing a clear hierarchical framework for the easy sharing, comparison and (re-)interpretation of HDX data, Start2Fold intends to promote a better understanding of how the protein sequence encodes folding and structure as well as the development of new computational methods predicting protein folding and stability.
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Affiliation(s)
- Rita Pancsa
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium Structural Biology Research Center (IB), VIB, Brussels 1050, Belgium
| | - Mihaly Varadi
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium Structural Biology Research Center (IB), VIB, Brussels 1050, Belgium
| | - Peter Tompa
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium Structural Biology Research Center (IB), VIB, Brussels 1050, Belgium Interuniversity Institute of Bioinformatics in Brussels (IB), ULB-VUB, Brussels 1050, Belgium Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1113, Hungary
| | - Wim F Vranken
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium Structural Biology Research Center (IB), VIB, Brussels 1050, Belgium Interuniversity Institute of Bioinformatics in Brussels (IB), ULB-VUB, Brussels 1050, Belgium
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6
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Evidence for close side-chain packing in an early protein folding intermediate previously assumed to be a molten globule. Proc Natl Acad Sci U S A 2014; 111:14746-51. [PMID: 25258414 DOI: 10.1073/pnas.1410630111] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molten globule, a conformational ensemble with significant secondary structure but only loosely packed tertiary structure, has been suggested to be a ubiquitous intermediate in protein folding. However, it is difficult to assess the tertiary packing of transiently populated species to evaluate this hypothesis. Escherichia coli RNase H is known to populate an intermediate before the rate-limiting barrier to folding that has long been thought to be a molten globule. We investigated this hypothesis by making mimics of the intermediate that are the ground-state conformation at equilibrium, using two approaches: a truncation to generate a fragment mimic of the intermediate, and selective destabilization of the native state using point mutations. Spectroscopic characterization and the response of the mimics to further mutation are consistent with studies on the transient kinetic intermediate, indicating that they model the early intermediate. Both mimics fold cooperatively and exhibit NMR spectra indicative of a closely packed conformation, in contrast to the hypothesis of molten tertiary packing. This result is important for understanding the nature of the subsequent rate-limiting barrier to folding and has implications for the assumption that many other proteins populate molten globule folding intermediates.
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7
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Jennaro TS, Beaty MR, Kurt-Yilmaz N, Luskin BL, Cavagnero S. Burial of nonpolar surface area and thermodynamic stabilization of globins as a function of chain elongation. Proteins 2014; 82:2318-31. [DOI: 10.1002/prot.24590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/11/2014] [Accepted: 04/12/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Theodore S. Jennaro
- Department of Chemistry; University of Wisconsin-Madison; Madison Wisconsin 53706
| | - Matthew R. Beaty
- Department of Chemistry; University of Wisconsin-Madison; Madison Wisconsin 53706
| | - Neşe Kurt-Yilmaz
- Department of Chemistry; University of Wisconsin-Madison; Madison Wisconsin 53706
| | - Benjamin L. Luskin
- Department of Chemistry; University of Wisconsin-Madison; Madison Wisconsin 53706
| | - Silvia Cavagnero
- Department of Chemistry; University of Wisconsin-Madison; Madison Wisconsin 53706
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Abstract
Fast-folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast-folding proteins has provided insight into the mechanisms, which allow some proteins to find their native conformation well <1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even 'slow' folding processes: fast folders are small; relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast-folding proteins and provides an overview of the major findings of fast-folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general, as well as some work that is left to do.
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9
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Chandak MS, Nakamura T, Takenaka T, Chaudhuri TK, Yagi-Utsumi M, Chen J, Kato K, Kuwajima K. The use of spin desalting columns in DMSO-quenched H/D-exchange NMR experiments. Protein Sci 2013; 22:486-91. [PMID: 23339068 DOI: 10.1002/pro.2221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/10/2013] [Accepted: 01/12/2012] [Indexed: 01/22/2023]
Abstract
Dimethylsulfoxide (DMSO)-quenched hydrogen/deuterium (H/D)-exchange is a powerful method to characterize the H/D-exchange behaviors of proteins and protein assemblies, and it is potentially useful for investigating non-protected fast-exchanging amide protons in the unfolded state. However, the method has not been used for studies on fully unfolded proteins in a concentrated denaturant or protein solutions at high salt concentrations. In all of the current DMSO-quenched H/D-exchange studies of proteins so far reported, lyophilization was used to remove D2 O from the protein solution, and the lyophilized protein was dissolved in the DMSO solution to quench the H/D exchange reactions and to measure the amide proton signals by two-dimensional nuclear magnetic resonance (2D NMR) spectra. The denaturants or salts remaining after lyophilization thus prevent the measurement of good NMR spectra. In this article, we report that the use of spin desalting columns is a very effective alternative to lyophilization for the medium exchange from the D2 O buffer to the DMSO solution. We show that the medium exchange by a spin desalting column takes only about 10 min in contrast to an overnight length of time required for lyophilization, and that the use of spin desalting columns has made it possible to monitor the H/D-exchange behavior of a fully unfolded protein in a concentrated denaturant. We report the results of unfolded ubiquitin in 6.0M guanidinium chloride.
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Affiliation(s)
- Mahesh S Chandak
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
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10
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Brock A. Fragmentation hydrogen exchange mass spectrometry: A review of methodology and applications. Protein Expr Purif 2012; 84:19-37. [DOI: 10.1016/j.pep.2012.04.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 04/13/2012] [Indexed: 01/19/2023]
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11
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pH-Dependent Conformational Transitions in Conalbumin (Ovotransferrin), a Metalloproteinase from Hen Egg White. Cell Biochem Biophys 2011; 61:551-60. [DOI: 10.1007/s12013-011-9237-x] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Nishimura C, Dyson HJ, Wright PE. Consequences of stabilizing the natively disordered f helix for the folding pathway of apomyoglobin. J Mol Biol 2011; 411:248-63. [PMID: 21640124 DOI: 10.1016/j.jmb.2011.05.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 05/16/2011] [Accepted: 05/18/2011] [Indexed: 10/18/2022]
Abstract
The F helix region of sperm whale apomyoglobin is disordered, undergoing conformational fluctuations between a folded helical conformation and one or more locally unfolded states. To examine the effects of F helix stabilization on the folding pathway of apomyoglobin, we have introduced mutations to augment intrinsic helical structure in the F helix of the kinetic folding intermediate and to increase its propensity to fold early in the pathway, using predictions based on plots of the average area buried upon folding (AABUF) derived from the primary sequence. Two mutant proteins were prepared: a double mutant, P88K/S92K (F2), and a quadruple mutant, P88K/A90L/S92K/A94L (F4). Whereas the AABUF for F2 predicts that the F helix will not fold early in the pathway, the F helix in F4 shows a significantly increased AABUF and is therefore predicted to fold early. Protection of amide protons by formation of hydrogen-bonded helical structure during the early folding events has been analyzed by pH-pulse labeling. Consistent with the AABUF prediction, many of the F helix residues for F4 are significantly protected in the kinetic intermediate but are not protected in the F2 mutant. F4 folds via a kinetically trapped burst-phase intermediate that contains stabilized secondary structure in the A, B, F, G, and H helix regions. Rapid folding of the F helix stabilizes the central core of the misfolded intermediate and inhibits translocation of the H helix back to its native position, thereby decreasing the overall folding rate.
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Affiliation(s)
- Chiaki Nishimura
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla CA 92037, USA
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13
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Khan MKA, Rahaman H, Ahmad F. Conformation and thermodynamic stability of pre-molten and molten globule states of mammalian cytochromes-c. Metallomics 2011; 3:327-38. [DOI: 10.1039/c0mt00078g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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14
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Bhuyan AK. Off-Pathway Status for the Alkali Molten Globule of Horse Ferricytochrome c. Biochemistry 2010; 49:7764-73. [DOI: 10.1021/bi100880d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Abani K. Bhuyan
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
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15
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Varshney A, Ahmad B, Rabbani G, Kumar V, Yadav S, Khan RH. Acid-induced unfolding of didecameric keyhole limpet hemocyanin: detection and characterizations of decameric and tetrameric intermediate states. Amino Acids 2010; 39:899-910. [DOI: 10.1007/s00726-010-0524-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
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Chevelkov V, Xue Y, Rao DK, Forman-Kay JD, Skrynnikov NR. 15N H/D-SOLEXSY experiment for accurate measurement of amide solvent exchange rates: application to denatured drkN SH3. JOURNAL OF BIOMOLECULAR NMR 2010; 46:227-244. [PMID: 20195703 DOI: 10.1007/s10858-010-9398-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Accepted: 02/03/2010] [Indexed: 05/28/2023]
Abstract
Amide solvent exchange rates are regarded as a valuable source of information on structure/dynamics of unfolded (disordered) proteins. Proton-based saturation transfer experiments, normally used to measure solvent exchange, are known to meet some serious difficulties. The problems mainly arise from the need to (1) manipulate water magnetization and (2) discriminate between multiple magnetization transfer pathways that occur within the proton pool. Some of these issues are specific to unfolded proteins. For example, the compensation scheme used to cancel the Overhauser effect in the popular CLEANEX experiment is not designed for use with unfolded proteins. In this report we describe an alternative experimental strategy, where amide (15)N is used as a probe of solvent exchange. The experiment is performed in 50% H(2)O-50% D(2)O solvent and is based on the (HACACO)NH pulse sequence. The resulting spectral map is fully equivalent to the conventional HSQC. To fulfill its purpose, the experiment monitors the conversion of deuterated species, (15)N(D), into protonated species, (15)N(H), as effected by the solvent exchange. Conceptually, this experiment is similar to EXSY which prompted the name of (15)N(H/D)-SOLEXSY (SOLvent EXchange SpectroscopY). Of note, our experimental scheme, which relies on nitrogen rather than proton to monitor solvent exchange, is free of the complications described above. The developed pulse sequence was used to measure solvent exchange rates in the chemically denatured state of the drkN SH3 domain. The results were found to correlate well with the CLEANEX-PM data, r = 0.97, thus providing a measure of validation for both techniques. When the experimentally measured exchange rates are converted into protection factors, most of the values fall in the range 0.5-2, consistent with random-coil behavior. However, elevated values, ca. 5, are obtained for residues R38 and A39, as well as the side-chain indole of W36. This is surprising, given that high protection factors imply hydrogen bonding or hydrophobic burial not expected to occur in a chemically denatured state of a protein. We, therefore, hypothesized that elevated protection factors are an artefact arising from the calculation of the reference (random-coil) exchange rates. To confirm this hypothesis, we prepared samples of several short peptides derived from the sequence of the drkN SH3 domain; these samples were used to directly measure the reference exchange rates. The revised protection factors obtained in this manner proved to be close to 1.0. These results also have implications for the more compact unfolded state of drkN SH3, which appears to be fully permeable to water as well, with no manifestations of hydrophobic burial.
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Affiliation(s)
- Veniamin Chevelkov
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907-2084, USA
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17
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Qu P, Lu H, Yan S, Lu Z. Influences of cationic, anionic, and nonionic surfactants on alkaline-induced intermediate of bovine serum albumin. Int J Biol Macromol 2010; 46:91-9. [DOI: 10.1016/j.ijbiomac.2009.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 10/12/2009] [Accepted: 10/17/2009] [Indexed: 10/20/2022]
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18
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Nabuurs SM, van Mierlo CPM. Interrupted hydrogen/deuterium exchange reveals the stable core of the remarkably helical molten globule of alpha-beta parallel protein flavodoxin. J Biol Chem 2009; 285:4165-4172. [PMID: 19959481 DOI: 10.1074/jbc.m109.087932] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kinetic intermediates that appear early during protein folding often resemble the relatively stable molten globule intermediates formed by several proteins under mildly denaturing conditions. Molten globules have a substantial amount of secondary structure but lack virtually all tertiary side-chain packing characteristics of natively folded proteins. Due to exposed hydrophobic groups, molten globules are prone to aggregation, which can have detrimental effects on organisms. The molten globule that is observed during folding of alpha-beta parallel flavodoxin from Azotobacter vinelandii is a remarkably non-native species. This folding intermediate is helical and contains no beta-sheet and is kinetically off-pathway to the native state. It can be trapped under native-like conditions by substituting residue Phe(44) for Tyr(44). To characterize this species at the residue level, in this study, use is made of interrupted hydrogen/deuterium exchange detected by NMR spectroscopy. In the molten globule of flavodoxin, the helical region comprising residues Leu(110)-Val(125) is shown to be better protected against exchange than the other ordered parts of the folding intermediate. This helical region is better buried than the other helices, causing its context-dependent stabilization against unfolding. Residues Leu(110)-Val(125) thus form the stable core of the helical molten globule of alpha-beta parallel flavodoxin, which is almost entirely structured. Non-native docking of helices in the molten globule of flavodoxin prevents formation of the parallel beta-sheet of native flavodoxin. Hence, to produce native alpha-beta parallel protein molecules, the off-pathway species needs to unfold.
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Affiliation(s)
- Sanne M Nabuurs
- From the Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Carlo P M van Mierlo
- From the Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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19
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Qu P, Lu H, Yan S, Zhou D, Lu Z. Investigations of effects of environmental factors in unfolding/refolding pathway of proteins on 8-anilino-1-naphthalene-sulfonic acid (ANS) fluorescence. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2009.07.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Kameda A, Morita EH, Sakurai K, Naiki H, Goto Y. NMR-based characterization of a refolding intermediate of beta2-microglobulin labeled using a wheat germ cell-free system. Protein Sci 2009; 18:1592-601. [PMID: 19606503 DOI: 10.1002/pro.179] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In patients with dialysis-related amyloidosis, beta2-microglobulin (beta2-m) is a major structural component of amyloid fibrils. It has been suggested that the partial unfolding of beta2-m is a prerequisite to the formation of amyloid fibrils, and that the folding intermediate trapped by the non-native trans-Pro32 isomer leads to the formation of amyloid fibrils. Although clarifying the structure of this refolding intermediate by high resolution NMR spectroscopy is important, this has been made difficult by the limited lifetime of the intermediate. Here, we studied the structure of the refolding intermediate using a combination of amino acid selective labeling with wheat germ cell-free protein synthesis and NMR techniques. The HSQC spectra of beta2-ms labeled selectively at either phenylalanine, leucine, or valine enabled us to monitor the structures of the refolding intermediate. The results suggested that the refolding intermediate has an overall fold and cores similar to the native structure, but contains disordered structures around Pro32. The fluctuation of the beta-sheet regions especially the last half of the betaB strand and the first half of the betaE strand, both suggested to be important for amyloidogenicity, may transform beta2-m into an amyloidogenic structure.
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Affiliation(s)
- Atsushi Kameda
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
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Muthuselvi L, Dhathathreyan A. Understanding dynamics of myoglobin in heterogeneous aqueous environments using coupled water fractions. Adv Colloid Interface Sci 2009; 150:55-62. [PMID: 19442960 DOI: 10.1016/j.cis.2009.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 04/08/2009] [Accepted: 04/08/2009] [Indexed: 11/19/2022]
Abstract
This work presents an analysis of near environment of myoglobin (Mb) in different aqueous solutions (in the presence of NaCl, sucrose, trehalose, urea, and glycerol) using the coupled water fractions measured using a quartz crystal microbalance (QCM). The secondary structural features of the protein from circular dichroic (CD) spectroscopy and the coupled water fractions give important clues to the overall dynamics of the protein. Using time resolved fluorescence, these leads have been applied to understand the observed lifetime relaxations of Mb. Though the time scales of observation of coupled water and the lifetimes are very different, our study suggests that the trends in coupled water fraction seem to be good indicators for regulation of the relaxation dynamics of the protein. The relaxations generally show a triphasic distribution of time scales. The initial relaxation in the picoseconds time scale represents the local motions of coupled water followed by a slightly slower decay in hundreds of picoseconds attributable to coupled water-'quasi free' water interactions. The third nanosecond lifetime is due to changes in transitions in isomers of hydrated protein. The dynamics of coupled water in Mb with NaCl is the fastest (around 21 ps) and is slowest in glycerol (250 ps). The results strongly indicate that it is the resident times of water molecules that play a dominant role in the overall stability of protein in a particular hydrated isomer and not just always the number of such water molecules in the hydrated protein.
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Affiliation(s)
- L Muthuselvi
- Chemical Lab., CLRI (CSIR), Adyar, Chennai 600 020, India
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Codutti L, Picotti P, Marin O, Dewilde S, Fogolari F, Corazza A, Viglino P, Moens L, Esposito G, Fontana A. Conformational stability of neuroglobin helix F--possible effects on the folding pathway within the globin family. FEBS J 2009; 276:5177-90. [PMID: 19674102 DOI: 10.1111/j.1742-4658.2009.07214.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuroglobin is a recently discovered member of the globin family, mainly observed in neurons and retina. Despite the low sequence identity (less than 20% over the whole sequence for the human proteins), the general fold of neuroglobin closely resembles that of myoglobin. The latter is a paradigmatic protein for folding studies, whereas much less is known about the neuroglobin folding pathway. In this work, we show how the structural features of helix F in neuroglobin and myoglobin could represent a pivotal difference in their folding pathways. Former studies widely documented that myoglobin lacks helix F in the apo form. In this study, limited proteolysis experiments on aponeuroglobin showed that helix F does not undergo proteolytic cleavage, suggesting that, also in the apo form, this helix maintains a rigid and structured conformation. To understand better the structural properties of helices F in the two proteins, we analyzed peptides encompassing helix F of neuroglobin and myoglobin in the wild-type and mutant forms. NMR and CD experiments revealed a helical conformation for neuroglobin helix F peptide, at both pH 7 and pH 2, absent in the myoglobin peptide. In particular, NMR data suggest a secondary structure stabilization effect caused by hydrophobic interactions involving Tyr88, Leu89 and Leu92. Molecular dynamics simulations performed on the apo and holo forms of the two proteins reveal the persistence of helix F in neuroglobin even in the absence of heme. Conversely myoglobin shows a higher mobility of the N-terminus of helix F on heme removal, which leads to the loss of secondary structure.
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Affiliation(s)
- Luca Codutti
- Department of Biomedical Sciences and Technologies and MATI Centre of Excellence, University of Udine, Italy
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Steward A, McDowell GS, Clarke J. Topology is the principal determinant in the folding of a complex all-alpha Greek key death domain from human FADD. J Mol Biol 2009; 389:425-37. [PMID: 19362094 PMCID: PMC2724026 DOI: 10.1016/j.jmb.2009.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 03/26/2009] [Accepted: 04/01/2009] [Indexed: 11/24/2022]
Abstract
In order to elucidate the relative importance of secondary structure and topology in determining folding mechanism, we have carried out a phi-value analysis of the death domain (DD) from human FADD. FADD DD is a 100 amino acid domain consisting of six anti-parallel alpha helices arranged in a Greek key structure. We asked how does the folding of this domain compare with that of (a) other all-alpha-helical proteins and (b) other Greek key proteins? Is the folding pathway determined mainly by secondary structure or is topology the principal determinant? Our Φ-value analysis reveals a striking resemblance to the all-beta Greek key immunoglobulin-like domains. Both fold via diffuse transition states and, importantly, long-range interactions between the four central elements of secondary structure are established in the transition state. The elements of secondary structure that are less tightly associated with the central core are less well packed in both cases. Topology appears to be the dominant factor in determining the pathway of folding in all Greek key domains.
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Affiliation(s)
- Annette Steward
- University of Cambridge, Department of Chemistry, MRC Centre for Protein Engineering, Lensfield Road, Cambridge, CB2 1EW, UK
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Milanesi L, Jelinska C, Hunter CA, Hounslow AM, Staniforth RA, Waltho JP. A Method for the Reversible Trapping of Proteins in Non-Native Conformations. Biochemistry 2008; 47:13620-34. [DOI: 10.1021/bi801362f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lilia Milanesi
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
| | - Clare Jelinska
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
| | - Christopher A. Hunter
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
| | - Andrea M. Hounslow
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
| | - Rosemary A. Staniforth
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
| | - Jonathan P. Waltho
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, U.K., Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K., and Faculty of Life Sciences and Manchester Interdisciplinary Biocentre, The University of Manchester, Manchester M1 7DN, U.K
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