1
|
Parigi G, Ravera E, Fragai M, Luchinat C. Unveiling protein dynamics in solution with field-cycling NMR relaxometry. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 124-125:85-98. [PMID: 34479712 DOI: 10.1016/j.pnmrs.2021.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 06/13/2023]
Abstract
Field-cycling NMR relaxometry is a well-established technique that can give information on molecular structure and dynamics of biological systems. It provides the nuclear relaxation rates as a function of the applied magnetic field, starting from fields as low as ~ 10-4 T up to about 1-3 T. The profiles so collected, called nuclear magnetic relaxation dispersion (NMRD) profiles, can be extended to include the relaxation rates at the largest fields achievable with high resolution NMR spectrometers. By exploiting this wide range of frequencies, the NMRD profiles can provide information on motions occurring on time scales from 10-6 to 10-9 s. 1H NMRD measurements have proved very useful also for the characterization of paramagnetic proteins, because they can help characterise a number of parameters including the number, distance and residence time of water molecules coordinated to the paramagnetic center, the reorientation correlation times and the electron spin relaxation time, and the electronic structure at the metal site.
Collapse
Affiliation(s)
- Giacomo Parigi
- Magnetic Resonance Center (CERM) University of Florence, via Sacconi 6, Sesto Fiorentino, Italy; Department of Chemistry, "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), via Sacconi 6, Sesto Fiorentino, Italy.
| | - Enrico Ravera
- Magnetic Resonance Center (CERM) University of Florence, via Sacconi 6, Sesto Fiorentino, Italy; Department of Chemistry, "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), via Sacconi 6, Sesto Fiorentino, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM) University of Florence, via Sacconi 6, Sesto Fiorentino, Italy; Department of Chemistry, "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), via Sacconi 6, Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) University of Florence, via Sacconi 6, Sesto Fiorentino, Italy; Department of Chemistry, "Ugo Schiff", University of Florence, via della Lastruccia 3, Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), via Sacconi 6, Sesto Fiorentino, Italy
| |
Collapse
|
3
|
Li Y, Xie Y, Wang Z, Zang N, Carniato F, Huang Y, Andolina CM, Parent LR, Ditri TB, Walter ED, Botta M, Rinehart JD, Gianneschi NC. Structure and Function of Iron-Loaded Synthetic Melanin. ACS NANO 2016; 10:10186-10194. [PMID: 27802021 PMCID: PMC5295137 DOI: 10.1021/acsnano.6b05502] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We describe a synthetic method for increasing and controlling the iron loading of synthetic melanin nanoparticles and use the resulting materials to perform a systematic quantitative investigation on their structure-property relationship. A comprehensive analysis by magnetometry, electron paramagnetic resonance, and nuclear magnetic relaxation dispersion reveals the complexities of their magnetic behavior and how these intraparticle magnetic interactions manifest in useful material properties such as their performance as MRI contrast agents. This analysis allows predictions of the optimal iron loading through a quantitative modeling of antiferromagnetic coupling that arises from proximal iron ions. This study provides a detailed understanding of this complex class of synthetic biomaterials and gives insight into interactions and structures prevalent in naturally occurring melanins.
Collapse
Affiliation(s)
- Yiwen Li
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Yijun Xie
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Zhao Wang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Nanzhi Zang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “A. Avogadro”, Alessandria, Italy
| | - Yuran Huang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Christopher M. Andolina
- Department of Chemistry, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Lucas R. Parent
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Treffly B. Ditri
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Eric D. Walter
- Institute for Integrated Catalysis, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “A. Avogadro”, Alessandria, Italy
| | - Jeffrey D. Rinehart
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Nathan C. Gianneschi
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| |
Collapse
|
4
|
Sun N, Dey A, Xiao Z, Wedd AG, Hodgson KO, Hedman B, Solomon EI. Solvation effects on S K-edge XAS spectra of Fe-S proteins: normal and inverse effects on WT and mutant rubredoxin. J Am Chem Soc 2011; 132:12639-47. [PMID: 20726554 DOI: 10.1021/ja102807x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
S K-edge X-ray absorption spectroscopy (XAS) was performed on wild type Cp rubredoxin and its Cys --> Ser mutants in both solution and lyophilized forms. For wild type rubredoxin and for the mutants where an interior cysteine residue (C6 or C39) is substituted by serine, a normal solvent effect is observed, that is, the S covalency increases upon lyophilization. For the mutants where a solvent accessible surface cysteine residue is substituted by serine, the S covalency decreases upon lyophilization which is an inverse solvent effect. Density functional theory (DFT) calculations reproduce these experimental results and show that the normal solvent effect reflects the covalency decrease due to solvent H-bonding to the surface thiolates and that the inverse solvent effect results from the covalency compensation from the interior thiolates. With respect to the Cys --> Ser substitution, the S covalency decreases. Calculations indicate that the stronger bonding interaction of the alkoxide with the Fe relative to that of thiolate increases the energy of the Fe d orbitals and reduces their bonding interaction with the remaining cysteines. The solvent effects support a surface solvent tuning contribution to electron transfer, and the Cys --> Ser result provides an explanation for the change in properties of related iron-sulfur sites with this mutation.
Collapse
Affiliation(s)
- Ning Sun
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | | | | | | | | | | | | |
Collapse
|