title: Response to copper stress in Streptomyces lividans extends beyond genes under direct control of a copper-sensitive operon repressor protein (CsoR).
abstract: A copper-sensitive operon repressor protein (CsoR) has been identified in Streptomyces lividans (CsoR(Sl)) and found to regulate copper homeostasis with attomolar affinity for Cu(I). Solution studies reveal apo- and Cu(I)-CsoR(Sl) to be a tetramer assembly, and a 1.7-Å resolution crystal structure of apo-CsoR(Sl) reveals that a significant conformational change is necessary to enable Cu(I) binding. In silico prediction of the CsoR regulon was confirmed in vitro (EMSA) and in vivo (RNA-seq), which highlighted that next to the csoR gene itself, the regulon consists of two Cu(I) efflux systems involving a CopZ-like copper metallochaperone protein and a CopA P(1)-type ATPase. Although deletion of csoR has only minor effects on S. lividans development when grown under high copper concentrations, mutations of the Cu(I) ligands decrease tolerance to copper as a result of the Cu(I)-CsoR mutants failing to disengage from the DNA targets, thus inhibiting the derepression of the regulon. RNA-seq experiments carried out on samples incubated with exogenous copper and a ΔcsoR strain showed that the set of genes responding to copper stress is much wider than anticipated and largely extends beyond genes targeted by CsoR. This suggests more control levels are operating and directing other regulons in copper homeostasis beside the CsoR regulon.
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom.
authors.forename: Srivatsa
authors.initials: S
authors.lastname: Dwarakanath
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Chaplin
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Hough
authors.affiliation: Centre for Protein Engineering, Institut de Chimie B6a, University of Liège, B-4000 Liège, Belgium.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Rigali
authors.affiliation: Molecular Biotechnology, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P. O. Box 9502, 2300RA Leiden, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Vijgenboom
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom. Electronic address: jworrall@essex.ac.uk.
authors.forename: Jonathan A R
authors.initials: JAR
authors.lastname: Worrall
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D018360:Crystallography, X-Ray; D018085:Regulon / Q000502:physiology*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D048170:Streptomyces lividans / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; C071263:CopA protein, Bacteria; D012097:Repressor Proteins; D003300:Copper