학술논문

Elucidating the concentration-dependent effects of thiocyanate binding to carbonic anhydrase.
Document Type
Academic Journal
Author
Silva JM; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal.; Cerofolini L; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino 50019, Italy.; Carvalho AL; UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.; Ravera E; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy.; Fragai M; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy.; Parigi G; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy.; Macedo AL; UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.; Geraldes CFGC; Department of Life Sciences, Faculty of Science and Technology, 3000-393 Coimbra, Portugal; Coimbra Chemistry Center- Institute of Molecular Sciences (CCC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal.; Luchinat C; Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy; Giotto Biotech, S.R.L, Sesto Fiorentino, Florence 50019, Italy. Electronic address: luchinat@cerm.unifi.it.
Source
Publisher: Elsevier Country of Publication: United States NLM ID: 7905788 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-3344 (Electronic) Linking ISSN: 01620134 NLM ISO Abbreviation: J Inorg Biochem Subsets: MEDLINE
Subject
Language
English
Abstract
Many proteins naturally carry metal centers, with a large share of them being in the active sites of several enzymes. Paramagnetic effects are a powerful source of structural information and, therefore, if the native metal is paramagnetic, or it can be functionally substituted with a paramagnetic one, paramagnetic effects can be used to study the metal sites, as well as the overall structure of the protein. One notable example is cobalt(II) substitution for zinc(II) in carbonic anhydrase. In this manuscript we investigate the effects of sodium thiocyanate on the chemical environment of the metal ion of the human carbonic anhydrase II. The electron paramagnetic resonance (EPR) titration of the cobalt(II) protein with thiocyanate shows that the EPR spectrum changes from A-type to C-type on passing from 1:1 to 1:1000-fold ligand excess. This indicates the occurrence of a change in the electronic structure, which may reflect a sizable change in the metal coordination environment in turn caused by a modification of the frozen solvent glass. However, paramagnetic nuclear magnetic resonance (NMR) data indicate that the metal coordination cage remains unperturbed even in 1:1000-fold ligand excess. This result proves that the C-type EPR spectrum observed at large ligand concentration should be ascribed to the low temperature at which EPR measurements are performed, which impacts on the structure of the protein when it is destabilized by a high concentration of a chaotropic agent.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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