129610 20240104102231.0 doi 10.1042/BCJ20170692 sideral 103894 ART-2018-103894 eng Sein-Echaluce, Violeta C. Molecular basis for the integration of environmental signals by FurB from Anabaena sp. PCC 7120 2018 FUR (Ferric uptake regulator) proteins are among the most important families of transcriptional regulators in prokaryotes, often behaving as global regulators. In the cyanobacterium Anabaena PCC 7120, FurB (Zur, Zinc uptake regulator) controls zinc and redox homeostasis through the repression of target genes in a zinc-dependent manner. In vitro, non-specific binding of FurB to DNA elicits protection against oxidative damage and avoids cleavage by deoxyribonuclease I. The present study provides, for the first time, evidence of the influence of redox environment in the interaction of FurB with regulatory zinc and its consequences in FurB–DNA-binding affinity. Calorimetry studies showed that, in addition to one structural Zn(II), FurB is able to bind two additional Zn(II) per monomer and demonstrated the implication of cysteine C93 in regulatory Zn(II) coordination. The interaction of FurB with the second regulatory zinc occurred only under reducing conditions. While non-specific FurB–DNA interaction is Zn(II)-independent, the optimal binding of FurB to target promoters required loading of two regulatory zinc ions. Those results combined with site-directed mutagenesis and gel-shift assays evidenced that the redox state of cysteine C93 conditions the binding of the second regulatory Zn(II) and, in turn, modulates the affinity for a specific DNA target. Furthermore, differential spectroscopy studies showed that cysteine C93 could also be involved in heme coordination by FurB, either as a direct ligand or being located near the binding site. The results indicate that besides controlling zinc homeostasis, FurB could work as a redox-sensing protein probably modifying its zinc and DNA-binding abilities depending upon environmental conditions. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA/B18 info:eu-repo/grantAgreement/ES/MINECO/BFU2012-31458 info:eu-repo/grantAgreement/ES/MINECO/BFU2016-77671-P info:eu-repo/grantAgreement/ES/UZ/UZ-2016-BIO-02 info:eu-repo/semantics/openAccess by-nc-nd http://creativecommons.org/licenses/by-nc-nd/3.0/es/ 4.331 2018 BIOCHEMISTRY & MOLECULAR BIOLOGY 72 / 294 = 0.245 2018 Q1 T1 2.142 2018 Biochemistry 2018 Q1 Molecular Biology 2018 Q1 Cell Biology 2018 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Pallarés, María Carmen Lostao, Anabel Universidad de Zaragoza (orcid)0000-0001-7460-5916 Yruela, Inmaculada Universidad de Zaragoza (orcid)0000-0003-3608-4720 Velázquez-Campoy, Adrián Universidad de Zaragoza (orcid)0000-0001-5702-4538 Peleato, M. Luisa Universidad de Zaragoza (orcid)0000-0002-2742-3711 Fillat, Maria F. Universidad de Zaragoza (orcid)0000-0001-8644-4574 1002 412 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Fisiología Vegetal 1002 060 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Bioquímica y Biolog.Mole. 475, 1 (2018), 151-168 Biochem. j. Biochemical Journal 0264-6021 2240753 http://zaguan.unizar.es/record/129610/files/texto_completo.pdf Postprint 1178012 http://zaguan.unizar.es/record/129610/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:129610 articulos driver 2024-01-04-09:04:55 ARTICLE