title: Kinetic analysis of copper transfer from a chaperone to its target protein mediated by complex formation.
abstract: Chaperone proteins that traffic copper around the cell minimise its toxicity by maintaining it in a tightly bound form. The transfer of copper from chaperones to target proteins is promoted by complex formation, but the kinetic characteristics of transfer have yet to be demonstrated for any chaperone-target protein pair. Here we report studies of copper transfer between the Atx1-type chaperone CopZ from Bacillus subtilis and the soluble domains of its cognate P-type ATPase transporter, CopAab. Transfer of copper from CopZ to CopAab was found to occur rapidly, with a rate constant at 25 °C of ∼267 s-1, many orders of magnitude higher than that for Cu(i) dissociation from CopZ in the absence of CopAab. The data demonstrate that complex formation between CopZ and CopAab, evidence for which is provided by NMR and electrospray ionisation mass spectrometry, dramatically enhances the rate of Cu(i) dissociation from CopZ.
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Kristine L
authors.initials: KL
authors.lastname: Kay
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Tenori
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Justin M
authors.initials: JM
authors.lastname: Bradley
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Chloe
authors.initials: C
authors.lastname: Singleton
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Kihlken
authors.affiliation: Magnetic Resonance Center CERM and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Ciofi-Baffoni
authors.affiliation: Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK. n.le-brun@uea.ac.uk.
authors.forename: Nick E
authors.identifier: http://orcid.org/0000-0001-9780-4061
authors.initials: NE
authors.lastname: Le Brun
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry / Q000378:metabolism; D003300:Copper / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D013058:Mass Spectrometry; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D011789:Quantum Theory
chemical_list: D018832:Molecular Chaperones; D003300:Copper