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Milov AD, Tsvetkov YD, Gorbunova EY, Mustaeva LG, Ovchinnikova TV, Raap J. Self-aggregation properties of spin-labeled zervamicin IIA as studied by PELDOR spectroscopy. Biopolymers 2002; 64:328-36. [PMID: 12124850 DOI: 10.1002/bip.10208] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this article, the pulsed double electron-electron resonance in electron spin-echo (PELDOR) technique is applied to study the self-aggregation of spin-labeled zervamicin IIA, a hexadecapeptide antibiotic of fungal origin, which is known to form ion channels in a phospholipid double layer. Measurements of the ion channel forming properties and the antibiotic activity of the analog indicate that replacement of the C-terminal phenylalaninol by the amino-2,2,6,6-tetramethylpiperidinyloxy (TEMPO) residue does not influence the biophysical and biological properties. The dipole-dipole interaction between the spin labels of the fully biologically active peptide analog was studied in frozen (77 K) glassy solutions in different ratios of toluene-methanol. The spin-labeled zervamicin IIA molecules were shown to form aggregates. An average distance between the spin labels in the aggregates was estimated to be in the range of 25-35 A (depending on the solvent composition), indicating that the amphiphilic helical peptide molecules are oriented in an antiparallel fashion. Increasing of methanol content in the solution results in a loosening of the aggregate structure. It was shown that the fraction of aggregated zervamicin IIA molecules is less than 44-67% depending on the solvent composition. The general usefulness of the method to obtain structural long-range information in a range of several tens of angstroms is demonstrated by comparison with the peptide cluster of trichogin GA IV.
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Affiliation(s)
- A D Milov
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation
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Borbat PP, McHaourab HS, Freed JH. Protein structure determination using long-distance constraints from double-quantum coherence ESR: study of T4 lysozyme. J Am Chem Soc 2002; 124:5304-14. [PMID: 11996571 DOI: 10.1021/ja020040y] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the use of a novel pulsed ESR technique for distance measurement, based on the detection of double quantum coherence (DQC), which yields high quality dipolar spectra, to significantly extend the range of measurable distances in proteins using nitroxide spin-labels. Eight T4 lysozyme (T4L) mutants, doubly labeled with methanethiosulfonate spin-label (MTSSL), have been studied using DQC-ESR at 9 and 17 GHz. The distances span the range from 20 A for the 65/76 mutant to 47 A for the 61/135 mutant. The high quality of the dipolar spectra also allows the determination of the distance distributions, the width of which can be used to set upper and lower bounds in future computational strategy. It is also demonstrated that the shape of these distributions can reveal the presence of multiple conformations of the spin-label, an issue of critical relevance to the structural interpretation of the distances. The distances and distributions found in this study are readily rationalized in terms of the known crystal structure, the characteristic conformers of the nitroxide side chains, and molecular modeling. This study sets the stage for the use of DQC-ESR for determining the tertiary structure of large proteins with just a small number of long-distance constraints.
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Affiliation(s)
- Petr P Borbat
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
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Milov AD, Tsvetkov YD, Formaggio F, Crisma M, Toniolo C, Millhauser GL, Raap J. Self-Assembling Properties of a Membrane-Modifying Lipopeptaibol in Weakly Polar Solvents Studied by CW ESR. J Phys Chem B 2001. [DOI: 10.1021/jp011948y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. D. Milov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Yu. D. Tsvetkov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - F. Formaggio
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - M. Crisma
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - C. Toniolo
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - G. L. Millhauser
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - J. Raap
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Biopolymer Research Center, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
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