Cysteine Mutational Studies Provide Insight into a Thiol-Based Redox Switch Mechanism of Metal and DNA Binding in FurA from Anabaena sp PCC 7120
Por:
Botello-Morte, L, Pellicer, S, Sein-Echaluce, V, Contreras, L, Neira, J, Abian, O, Velazquez-Campoy, A, Peleato, M, Fillat, M and Bes, M
Publicada:
1 feb 2016
Resumen:
Aims: The ferric uptake regulator (Fur) is the main transcriptional regulator of genes involved in iron homeostasis in most prokaryotes. FurA from Anabaena sp. PCC 7120 contains five cysteine residues, four of them arranged in two redox-active CXXC motifs. The protein needs not only metal but also reducing conditions to remain fully active in vitro. Through a mutational study of the cysteine residues present in FurA, we have investigated their involvement in metal and DNA binding. Results: Residue C-101 that belongs to a conserved CXXC motif plays an essential role in both metal and DNA binding activities in vitro. Substitution of C-101 by serine impairs DNA and metal binding abilities of FurA. Isothermal titration calorimetry measurements show that the redox state of C-101 is responsible for the protein ability to coordinate the metal corepressor. Moreover, the redox state of C-101 varies with the presence or absence of C-104 or C-133, suggesting that the environments of these cysteines are mutually interdependent. Innovation: We propose that C-101 is part of a thiol/disulfide redox switch that determines FurA ability to bind the metal corepressor. Conclusion: This mechanism supports a novel feature of a Fur protein that emerges as a regulator, which connects the response to changes in the intracellular redox state and iron management in cyanobacteria.
Filiaciones:
Botello-Morte, L:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Pellicer, S:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Sein-Echaluce, V:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Contreras, L:
Miguel Hernandez Univ Elche, Inst Mol & Cellular Biol, Elche, Spain
:
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Miguel Hernandez Univ Elche, Inst Mol & Cellular Biol, Elche, Spain
Abian, O:
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
IIS Aragon Aragon Hlth Sci Inst IACS, Zaragoza, Spain
Networked Biomed Res Ctr Hepat & Digest Dis CIBER, Zaragoza, Spain
Velazquez-Campoy, A:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Govt Aragon, ARAID Fdn, Zaragoza, Spain
Peleato, M:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Fillat, M:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
Bes, M:
Univ Zaragoza, Dept Biochem & Mol & Cell Biol, C Pedro Cerbuna 12, E-50009 Zaragoza, Spain
Univ Zaragoza, Inst Biocomputat & Phys Complex Syst BIFI Associa, IQRS CSIC, E-50009 Zaragoza, Spain
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