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Zhu Z, Bian Y, Zhang X, Zeng R, Yang B. Evaluation of formation and proportion of secondary structure in γ-polyglutamic acid by terahertz time-domain spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 271:120940. [PMID: 35093819 DOI: 10.1016/j.saa.2022.120940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The study of secondary structure is essential for understanding peptides and proteins. Here, we measured the terahertz (THz) spectra of γ-polyglutamic acid (γ-PGA) dominated by α-helix and random coil (RC) respectively. The α-helix has two absorption peaks in the THz region, but no absorption peak is observed in the RC conformation. We believe this is because the hydrogen bonding effect leads to a higher orientation in the helix-dominated γ-PGA. At lower pH, the absorption intensity of γ-PGA increases with the induction time. Similar changes were obtained in the Fourier infrared spectroscopy (FTIR). Through the correlation analysis of THz and IR spectroscopy, it is found that the characteristic peak at 1.2 THz can be used as a sensitive indicator of the intermediate conformation of the α-helical structure. In addition, the transformation of α-helix-RC conformation is related to the peak intensity at 1.99 THz (R2 = 0.991), which preliminarily indicates that terahertz time-domain spectroscopy (THz-TDS) has the potential to become a new effective method for characterizing and evaluating secondary structure.
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Affiliation(s)
- Zhenqi Zhu
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China
| | - Yujing Bian
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China
| | - Xun Zhang
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China
| | - Ruonan Zeng
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China
| | - Bin Yang
- College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, PR China; Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, PR China.
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Casier R, Duhamel J. Effect of Like Charges on the Conformation and Internal Dynamics of Polypeptides Probed by Pyrene Excimer Fluorescence. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00836] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Remi Casier
- Institute for Polymer Research, Department of Chemistry, Waterloo Institute for Nanotechnology, Waterloo N2L3G1, Ontario, Canada
| | - Jean Duhamel
- Institute for Polymer Research, Department of Chemistry, Waterloo Institute for Nanotechnology, Waterloo N2L3G1, Ontario, Canada
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Gryaznova Y, Caydasi AK, Malengo G, Sourjik V, Pereira G. A FRET-based study reveals site-specific regulation of spindle position checkpoint proteins at yeast centrosomes. eLife 2016; 5:e14029. [PMID: 27159239 PMCID: PMC4878874 DOI: 10.7554/elife.14029] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/08/2016] [Indexed: 12/19/2022] Open
Abstract
The spindle position checkpoint (SPOC) is a spindle pole body (SPB, equivalent of mammalian centrosome) associated surveillance mechanism that halts mitotic exit upon spindle mis-orientation. Here, we monitored the interaction between SPB proteins and the SPOC component Bfa1 by FRET microscopy. We show that Bfa1 binds to the scaffold-protein Nud1 and the γ-tubulin receptor Spc72. Spindle misalignment specifically disrupts Bfa1-Spc72 interaction by a mechanism that requires the 14-3-3-family protein Bmh1 and the MARK/PAR-kinase Kin4. Dissociation of Bfa1 from Spc72 prevents the inhibitory phosphorylation of Bfa1 by the polo-like kinase Cdc5. We propose Spc72 as a regulatory hub that coordinates the activity of Kin4 and Cdc5 towards Bfa1. In addition, analysis of spc72∆ cells shows that a mitotic-exit-promoting dominant signal, which is triggered upon elongation of the spindle into the bud, overrides the SPOC. Our data reinforce the importance of daughter-cell-associated factors and centrosome-based regulations in mitotic exit and SPOC control.
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Affiliation(s)
- Yuliya Gryaznova
- DKFZ-ZMBH Alliance, German Cancer Research Centre, Heidelberg, Germany
| | - Ayse Koca Caydasi
- DKFZ-ZMBH Alliance, German Cancer Research Centre, Heidelberg, Germany
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Gabriele Malengo
- DKFZ-ZMBH Alliance, Centre for Molecular Biology, Heidelberg, Germany
| | - Victor Sourjik
- DKFZ-ZMBH Alliance, Centre for Molecular Biology, Heidelberg, Germany
| | - Gislene Pereira
- DKFZ-ZMBH Alliance, German Cancer Research Centre, Heidelberg, Germany
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
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Malachowski L, Holcombe JA. Comparison of immobilized poly-l-aspartic acid and poly-l-glutamic acid for chelation of metal cations. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nishio T. Monte Carlo studies on potentiometric titration of poly(glutamic acid). Biophys Chem 1998; 71:173-84. [PMID: 17029697 DOI: 10.1016/s0301-4622(98)00094-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/1997] [Revised: 12/08/1997] [Accepted: 12/25/1997] [Indexed: 11/16/2022]
Abstract
The potentiometric titration of poly(glutamic acid) with special attention to its helix-coil transition is investigated in terms of the previously developed Monte Carlo method. The simulations of the potentiometric titration are carried out for helical and coiled form of the peptide, separately. A cylindrical rod with spherical ionizable groups is adopted as each conformational model of poly(glutamic acid) molecule. A spherical charge with a hard core potential is assumed as a mobile hydrated ion. The helix-coil transition curves are analyzed by the Zimm-Bragg theory. A satisfactory agreement is achieved for the titration curves with the experimental data in most cases. The significance and the limitations of the simulation method are discussed.
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Affiliation(s)
- T Nishio
- Department of Physics, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
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Cesàro A, Paoletti S, Guidugli S, Benegas JC. Polyelectrolytic aspects of the titration curve pH-induced conformational transition of poly(l-glutamic acid): The semi-flexible model. Biophys Chem 1991; 39:9-16. [PMID: 17014763 DOI: 10.1016/0301-4622(91)85002-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/1989] [Revised: 03/26/1990] [Accepted: 05/17/1990] [Indexed: 10/18/2022]
Abstract
The cooperative conformational transition of poly(L-glutamic acid) induced by pH is monitored by the titration curves from literature. The polyelectrolytic approach described in the preceding article (A. Cesàro, S. Paoletti and J.C. Benegas, Biophys. Chem. 39 (1991) 1) is used to fit the experimental curves under various conditions of ionic strength and temperature, with the sole assumption that each polymeric state is characterized by a proper conformational flexibility. The helix-coil transition of the system becomes molecularly defined by the balance between the non-ionic conformational energy and the repulsive electrostatic energy of the two forms. Implications of the results of the theoretical model on the energetics of the cooperative order-disorder transition are discussed.
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Affiliation(s)
- A Cesàro
- Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università di Trieste, 34127 Trieste, Italy
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Paoletti S, Cesàro A, Samper CA, Benegas JC. Conformational transition of poly(alpha-L-glutamic acid). A polyelectrolytic approach. Biophys Chem 1989; 34:301-9. [PMID: 2482088 DOI: 10.1016/0301-4622(89)80067-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The charge-induced conformational transition of poly(alpha-L-glutamic acid) (PLGA) is considered in this paper from the point of view of proton dissociation. Equations for the excess electrostatic Gibbs energy of dissociation (i.e., delta pKa) are derived as a function of the degree of ionization, alpha. These analytical equations are used to describe some experimental dissociation curves at different polymer and salt concentrations. The dependence of the calculated delta pKa with respect to the ionic strength for the two conformational states, alpha-helical and extended coil, respectively, is rather satisfactorily explained. Even more interesting are the predictions which are derived from this approach for the transition point, alpha tr which is found to be ionic-strength dependent, in full agreement with the experimental results.
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Affiliation(s)
- S Paoletti
- Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università di Trieste, Italy
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Abstract
Recent studies on the (hypercoiled) compact conformation and the pH-induced conformational transition to the extended coil of the hydrophobic poly(acids or bases), which have been well used in industrial and medical circles, are summarized, especially on the basis of our studies on poly(alpha-alkyl acrylic acids) and maleic acid copolymers with hydrophobic aromatic monomers. The stability of the compact conformation and values of various thermodynamic parameters of the transition of the hydrophobic polyelectrolytes suggest the importance of hydrophobic interaction among the side chains to form the compact conformation. Characterization of various physicochemical methods, including 1H-NMR measurements, gives a model of the compact conformation with a more expanded structure than in globular proteins, a free-draining property of the solvent, the conformation fluctuation, etc. Also, the apparent two-state character of each segment in the transition region, a life-time in each state and the cooperative parameter for the compact form formation are discussed. A review of our conformational studies on the hydrophobic-hydrophilic polypeptides is also given. For the anion-induced conformation transition in basic homopoly(alpha-amino acids), hydrophobic characters of the anion and the side chain in the polypeptide are shown to be important, especially in terms of solvation. The difference in the induced conformation by the anion between random and alternating basic copolypeptides is explained by introducing a model which shows the importance of the sequence of hydrophobic and hydrophilic residues in the polypeptide to induce the ordered conformation of the anions. Also, we attempt to explain the difference between the induction of ordered conformation in the basic homo- or copolypeptide in reversed micelles with a large sulfonate (AOT) vs. that in aqueous AOT in terms of the hydrophobic character of the side chains in the polypeptides, AOT and the medium.
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Affiliation(s)
- S Sugai
- Department of Polymer Science, Faculty of Science, Hokkaido University, Japan
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Muller G. Charge-induced order-disorder transition in an ionic polysaccharide derived from schizophyllan. Carbohydr Polym 1986. [DOI: 10.1016/0144-8617(86)90018-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Masujima T, Yamaoka K, Hori JI. Conformational Changes of the Poly(α-L-glutamic acid)–Cu(II) Macromolecular Complexes in the pH Range 4–7. A Comparative Study by Means of Viscosity and Circular Dichroism. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1983. [DOI: 10.1246/bcsj.56.1030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Sugai S, Nitta K, Ohno N, Nakano H. Conformational studies on poly(ethacrylic acid) in aqueous salts by potentiometric, viscometric, optical and1H-NMR measurements. Colloid Polym Sci 1983. [DOI: 10.1007/bf01410696] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ohno N. Conformational Transition of the Copolymer of Maleic Acid and α-Methylstyrene in Aqueous Solution. Polym J 1981. [DOI: 10.1295/polymj.13.719] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bittner H, Schönert H. Bimodale Diffussion von Polymethacrylsäure in wässrigen Lösungen im Konformationsumwandlungsbereich. Colloid Polym Sci 1977. [DOI: 10.1007/bf01773527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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