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Dudev T, Grauffel C, Lim C. How Pb2+ Binds and Modulates Properties of Ca2+-Signaling Proteins. Inorg Chem 2018; 57:14798-14809. [DOI: 10.1021/acs.inorgchem.8b02548] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Todor Dudev
- Faculty of Chemistry and Pharmacy, Sofia University, Sofia 1164, Bulgaria
| | - Cédric Grauffel
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan
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Katti S, Her B, Srivastava AK, Taylor AB, Lockless SW, Igumenova TI. High affinity interactions of Pb 2+ with synaptotagmin I. Metallomics 2018; 10:1211-1222. [PMID: 30063057 DOI: 10.1039/c8mt00135a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Lead (Pb) is a potent neurotoxin that disrupts synaptic neurotransmission. We report that Synaptotagmin I (SytI), a key regulator of Ca2+-evoked neurotransmitter release, has two high-affinity Pb2+ binding sites that belong to its cytosolic C2A and C2B domains. The crystal structures of Pb2+-complexed C2 domains revealed that protein-bound Pb2+ ions have holodirected coordination geometries and all-oxygen coordination spheres. The on-rate constants of Pb2+ binding to the C2 domains of SytI are comparable to those of Ca2+ and are diffusion-limited. In contrast, the off-rate constants are at least two orders of magnitude smaller, indicating that Pb2+ can serve as both a thermodynamic and kinetic trap for the C2 domains. We demonstrate, using NMR spectroscopy, that population of these sites by Pb2+ ions inhibits further Ca2+ binding despite the existing coordination vacancies. Our work offers a unique insight into the bioinorganic chemistry of Pb(ii) and suggests a mechanism by which low concentrations of Pb2+ ions can interfere with the Ca2+-dependent function of SytI in the cell.
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Affiliation(s)
- Sachin Katti
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA.
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Morales KA, Lasagna M, Gribenko AV, Yoon Y, Reinhart GD, Lee JC, Cho W, Li P, Igumenova TI. Pb2+ as modulator of protein-membrane interactions. J Am Chem Soc 2011; 133:10599-611. [PMID: 21615172 DOI: 10.1021/ja2032772] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lead is a potent environmental toxin that mimics the effects of divalent metal ions, such as zinc and calcium, in the context of specific molecular targets and signaling processes. The molecular mechanism of lead toxicity remains poorly understood. The objective of this work was to characterize the effect of Pb(2+) on the structure and membrane-binding properties of C2α. C2α is a peripheral membrane-binding domain of Protein Kinase Cα (PKCα), which is a well-documented molecular target of lead. Using NMR and isothermal titration calorimetry (ITC) techniques, we established that C2α binds Pb(2+) with higher affinity than its natural cofactor, Ca(2+). To gain insight into the coordination geometry of protein-bound Pb(2+), we determined the crystal structures of apo and Pb(2+)-bound C2α at 1.9 and 1.5 Å resolution, respectively. A comparison of these structures revealed that the metal-binding site is not preorganized and that rotation of the oxygen-donating side chains is required for the metal coordination to occur. Remarkably, we found that holodirected and hemidirected coordination geometries for the two Pb(2+) ions coexist within a single protein molecule. Using protein-to-membrane Förster resonance energy transfer (FRET) spectroscopy, we demonstrated that Pb(2+) displaces Ca(2+) from C2α in the presence of lipid membranes through the high-affinity interaction with the membrane-unbound C2α. In addition, Pb(2+) associates with phosphatidylserine-containing membranes and thereby competes with C2α for the membrane-binding sites. This process can contribute to the inhibitory effect of Pb(2+) on the PKCα activity.
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Affiliation(s)
- Krystal A Morales
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
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Devereux M, van Severen MC, Parisel O, Piquemal JP, Gresh N. Role of Cation Polarization in holo- and hemi-Directed [Pb(H2O)n]2+ Complexes and Development of a Pb2+ Polarizable Force Field. J Chem Theory Comput 2010; 7:138-47. [DOI: 10.1021/ct1004005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mike Devereux
- Université Paris Descartes, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, UFR Biomédicale, 45 rue des Saints-Pères, 75270 Paris Cedex06, France; UPMC, Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005 Paris, France; and CNRS, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France
| | - Marie-Céline van Severen
- Université Paris Descartes, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, UFR Biomédicale, 45 rue des Saints-Pères, 75270 Paris Cedex06, France; UPMC, Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005 Paris, France; and CNRS, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France
| | - Olivier Parisel
- Université Paris Descartes, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, UFR Biomédicale, 45 rue des Saints-Pères, 75270 Paris Cedex06, France; UPMC, Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005 Paris, France; and CNRS, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France
| | - Jean-Philip Piquemal
- Université Paris Descartes, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, UFR Biomédicale, 45 rue des Saints-Pères, 75270 Paris Cedex06, France; UPMC, Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005 Paris, France; and CNRS, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France
| | - Nohad Gresh
- Université Paris Descartes, Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, UFR Biomédicale, 45 rue des Saints-Pères, 75270 Paris Cedex06, France; UPMC, Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case Courrier 137, 4 Place Jussieu, F-75005 Paris, France; and CNRS, UMR 7616, Laboratoire de Chimie Théorique, case courrier 137, 4 place Jussieu, F-75005 Paris, France
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