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Siddaramaiah M, Satyamoorthy K, Rao BSS, Roy S, Chandra S, Mahato KK. Identification of protein secondary structures by laser induced autofluorescence: A study of urea and GnHCl induced protein denaturation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 174:44-53. [PMID: 27875744 DOI: 10.1016/j.saa.2016.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 11/11/2016] [Accepted: 11/12/2016] [Indexed: 06/06/2023]
Abstract
In the present study an attempt has been made to interrogate the bulk secondary structures of some selected proteins (BSA, HSA, lysozyme, trypsin and ribonuclease A) under urea and GnHCl denaturation using laser induced autofluorescence. The proteins were treated with different concentrations of urea (3M, 6M, 9M) and GnHCl (2M, 4M, 6M) and the corresponding steady state autofluorescence spectra were recorded at 281nm pulsed laser excitations. The recorded fluorescence spectra of proteins were then interpreted based on the existing PDB structures of the proteins and the Trp solvent accessibility (calculated using "Scratch protein predictor" at 30% threshold). Further, the influence of rigidity and conformation of the indole ring (caused by protein secondary structures) on the intrinsic fluorescence properties of proteins were also evaluated using fluorescence of ANS-HSA complexes, CD spectroscopy as well as with trypsin digestion experiments. The outcomes obtained clearly demonstrated GnHCl preferably disrupt helix as compared to the beta β-sheets whereas, urea found was more effective in disrupting β-sheets as compared to the helices. The other way round the proteins which have shown detectable change in the intrinsic fluorescence at lower concentrations of GnHCl were rich in helices whereas, the proteins which showed detectable change in the intrinsic fluorescence at lower concentrations of urea were rich in β-sheets. Since high salt concentrations like GnHCl and urea interfere in the secondary structure analysis by circular dichroism Spectrometry, the present method of analyzing secondary structures using laser induced autofluorescence will be highly advantageous over existing tools for the same.
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Affiliation(s)
- Manjunath Siddaramaiah
- Department of Biophysics, School of Life Sciences, Manipal University, Manipal, Karnataka 576104, India
| | | | - Bola Sadashiva Satish Rao
- Department of Radiation Biology and Toxicology, School of Life Sciences, Manipal University, Manipal, Karnataka 576104, India
| | - Suparna Roy
- School of Life Sciences, Manipal University, Manipal, Karnataka 576104, India
| | - Subhash Chandra
- Department of Biophysics, School of Life Sciences, Manipal University, Manipal, Karnataka 576104, India
| | - Krishna Kishore Mahato
- Department of Biophysics, School of Life Sciences, Manipal University, Manipal, Karnataka 576104, India.
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Kuyucak S, Kayser V. Biobetters From an Integrated Computational/Experimental Approach. Comput Struct Biotechnol J 2017; 15:138-145. [PMID: 28179976 PMCID: PMC5279740 DOI: 10.1016/j.csbj.2017.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 02/04/2023] Open
Abstract
Biobetters are new drugs designed from existing peptide or protein-based therapeutics by improving their properties such as affinity and selectivity for the target epitope, and stability against degradation. Computational methods can play a key role in such design problems—by predicting the changes that are most likely to succeed, they can drastically reduce the number of experiments to be performed. Here we discuss the computational and experimental methods commonly used in drug design problems, focusing on the inverse relationship between the two, namely, the more accurate the computational predictions means the less experimental effort is needed for testing. Examples discussed include efforts to design selective analogs from toxin peptides targeting ion channels for treatment of autoimmune diseases and monoclonal antibodies which are the fastest growing class of therapeutic agents particularly for cancers and autoimmune diseases.
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Affiliation(s)
- Serdar Kuyucak
- School of Physics, University of Sydney, NSW 2006, Australia
- Corresponding author.
| | - Veysel Kayser
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
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Tkachev YV, Ge J, Negrashov IV, Nesmelov YE. Metal cation controls myosin and actomyosin kinetics. Protein Sci 2013; 22:1766-74. [PMID: 24115140 DOI: 10.1002/pro.2376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/26/2013] [Accepted: 09/08/2013] [Indexed: 11/07/2022]
Abstract
We have perturbed myosin nucleotide binding site with magnesium-, manganese-, or calcium-nucleotide complexes, using metal cation as a probe to examine the pathways of myosin ATPase in the presence of actin. We have used transient time-resolved FRET, myosin intrinsic fluorescence, fluorescence of pyrene labeled actin, combined with the steady state myosin ATPase activity measurements of previously characterized D.discoideum myosin construct A639C:K498C. We found that actin activation of myosin ATPase does not depend on metal cation, regardless of the cation-specific kinetics of nucleotide binding and dissociation. The rate limiting step of myosin ATPase depends on the metal cation. The rate of the recovery stroke and the reverse recovery stroke is directly proportional to the ionic radius of the cation. The rate of nucleotide release from myosin and actomyosin, and ATP binding to actomyosin depends on the cation coordination number.
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Affiliation(s)
- Yaroslav V Tkachev
- Department of Physics and Optical Science, University of North Carolina, Charlotte, North Carolina, 28223; Engelhardt Institute of Molecular Biology RAS, Moscow, 119991, Russia
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Wazawa T, Yasui SI, Morimoto N, Suzuki M. 1,3-Diethylurea-enhanced Mg-ATPase activity of skeletal muscle myosin with a converse effect on the sliding motility. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2620-9. [PMID: 23954499 DOI: 10.1016/j.bbapap.2013.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 12/01/2022]
Abstract
We investigate the effects of urea and its derivatives on the ATPase activity and on the in vitro motility of chicken skeletal muscle actomyosin. Mg-ATPase rate of myosin subfragment-1 (S1) is increased by 4-fold by 0.3M 1,3-diethylurea (DEU), but it is unaffected by urea, thiourea, and 1,3-dimethylurea at ≤1M concentration. Thus, we further examine the effects of DEU in comparison to those of urea as reference. In in vitro motility assay, we find that in the presence of 0.3M DEU, the sliding speeds of actin filaments driven by myosin and heavy meromyosin (HMM) are significantly decreased to 1/16 and 1/6.6, respectively, compared with the controls. However, the measurement of the actin-activated ATPase activity of HMM shows that the maximal rate, Vmax, is almost unchanged with DEU. Thus, the myosin-driven sliding motility of actin filaments is significantly impeded in the presence of 0.3M DEU, whereas the cyclic interaction of myosin with F-actin occurs during the ATP turnover, the rate of which is close to that without DEU. In contrast to DEU, 0.3M urea exhibits only modest effects on both actin-activated ATPase and sliding motility of actomyosin. Thus, DEU has the effect of uncoupling the sliding motility of actomyosin from its ATP turnover.
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Affiliation(s)
- Tetsuichi Wazawa
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, Aoba-yama 02, Aoba-ku, Sendai 980-8579, Japan
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Tryptophan-Tryptophan Energy Transfer and Classification of Tryptophan Residues in Proteins Using a Therapeutic Monoclonal Antibody as a Model. J Fluoresc 2010; 21:275-88. [DOI: 10.1007/s10895-010-0715-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 09/08/2010] [Indexed: 10/19/2022]
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Thomas DD, Kast D, Korman VL. Site-directed spectroscopic probes of actomyosin structural dynamics. Annu Rev Biophys 2009; 38:347-69. [PMID: 19416073 DOI: 10.1146/annurev.biophys.35.040405.102118] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spectroscopy of myosin and actin has entered a golden age. High-resolution crystal structures of isolated actin and myosin have been used to construct detailed models for the dynamic actomyosin interactions that move muscle. Improved protein mutagenesis and expression technologies have facilitated site-directed labeling with fluorescent and spin probes. Spectroscopic instrumentation has achieved impressive advances in sensitivity and resolution. Here we highlight the contributions of site-directed spectroscopic probes to understanding the structural dynamics of myosin II and its actin complexes in solution and muscle fibers. We emphasize studies that probe directly the movements of structural elements within the myosin catalytic and light-chain domains, and changes in the dynamics of both actin and myosin due to their alternating strong and weak interactions in the ATPase cycle. A moving picture emerges in which single biochemical states produce multiple structural states, and transitions between states of order and dynamic disorder power the actomyosin engine.
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Affiliation(s)
- David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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Shen C, Menon R, Das D, Bansal N, Nahar N, Guduru N, Jaegle S, Peckham J, Reshetnyak YK. The protein fluorescence and structural toolkit: Database and programs for the analysis of protein fluorescence and structural data. Proteins 2008; 71:1744-54. [DOI: 10.1002/prot.21857] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
The interdomain motions in myosin subfragment 1 (S1) were studied by steady-state and time-resolved fluorescence of tryptophan residues and N-(iodoacetyl)-N'-(5-sulfo-1-naphtyl)ethylenediamine (AEDANS) attached to Cys178 of alkali light chain 1 (A1) exchanged into S1. The efficiency of fluorescence resonance energy transfer (FRET) from tryptophan residues of motor domain to AEDANS at A1 decreased dramatically after addition of ATP to S1A1-AEDANS. The efficiency of FRET calculated from the crystal structure of chicken S1 corresponded to the experimental one measured in the presence of ATP. The results showed that AEDANS at Cys178 of A1 became more mobile and distant from the motor domain of S1 upon ATP binding. These findings led to the suggestion that a release of the products of ATP hydrolysis and power stroke might be associated with movement of light chain-binding domain towards the N-terminal domain of S1.
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Affiliation(s)
- Y K Reshetnyak
- Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA
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Reshetnyak YK, Burstein EA. Decomposition of protein tryptophan fluorescence spectra into log-normal components. II. The statistical proof of discreteness of tryptophan classes in proteins. Biophys J 2001; 81:1710-34. [PMID: 11509383 PMCID: PMC1301648 DOI: 10.1016/s0006-3495(01)75824-9] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The physical causes for wide variation of Stokes shift values in emission spectra of tryptophan fluorophores in proteins have been proposed in the model of discrete states (Burstein, E. A., N. S. Vedenkina, and M. N. Ivkova. 1973. Photochem. Photobiol. 18:263-279; Burstein, E. A. 1977a. Intrinsic Protein Luminescence (The Nature and Application). In Advances in Science and Technology (Itogi Nauki i Tekhniki), Biophysics Vol. 7. VINITI, Moscow [In Russian]; Burstein, E. A. 1983. Molecular Biology (Moscow) 17:455-467 [In Russian; English translation]). It was assumed that the existence of the five most probable spectral classes of emitting tryptophan residues and differences among the classes were analyzed in terms of various combinations of specific and universal interactions of excited fluorophores with their environment. The development of stable algorithms of decomposition of tryptophan fluorescence spectra into log-normal components gave us an opportunity to apply two mathematically different algorithms, SImple fitting with Mean-Square criterion (SIMS) and PHase-plot-based REsolving with Quenchers (PHREQ) for the decomposition of a representative set of emission spectra of proteins. Here we present the results of decomposition of tryptophan emission spectra of >100 different proteins, some in various structural states (native and denatured, in complexes with ions or organic ligands, in various pH-induced conformations, etc.). Analysis of the histograms of occurrence of >300 spectral log-normal components with various maximum positions confirmed the statistical discreteness of several states of emitting tryptophan fluorophores in proteins.
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Affiliation(s)
- Y K Reshetnyak
- Institute of Theoretical and Experimental Biophysics, Russia Academy of Sciences, Pushchino, Moscow Region, Russia 142290.
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