title: A new metal binding domain involved in cadmium, cobalt and zinc transport.
abstract: The P1B-ATPases, which couple cation transport across membranes to ATP hydrolysis, are central to metal homeostasis in all organisms. An important feature of P1B-ATPases is the presence of soluble metal binding domains (MBDs) that regulate transport activity. Only one type of MBD has been characterized extensively, but bioinformatics analyses indicate that a diversity of MBDs may exist in nature. Here we report the biochemical, structural and functional characterization of a new MBD from the Cupriavidus metallidurans P1B-4-ATPase CzcP (CzcP MBD). The CzcP MBD binds two Cd(2+), Co(2+) or Zn(2+) ions in distinct and unique sites and adopts an unexpected fold consisting of two fused ferredoxin-like domains. Both in vitro and in vivo activity assays using full-length CzcP, truncated CzcP and several variants indicate a regulatory role for the MBD and distinct functions for the two metal binding sites. Taken together, these findings elucidate a previously unknown MBD and suggest new regulatory mechanisms for metal transport by P1B-ATPases.
authors.affiliation: 1] Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA. [2] Department of Chemistry, Northwestern University, Evanston, Illinois, USA.
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Smith
authors.affiliation: Department of Pharmaceutical Sciences and Cardiovascular Research Institute, Wayne State University, School of Medicine, Detroit, Michigan, USA.
authors.forename: Dulmini
authors.initials: D
authors.lastname: Barupala
authors.affiliation: Department of Pharmaceutical Sciences and Cardiovascular Research Institute, Wayne State University, School of Medicine, Detroit, Michigan, USA.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Stemmler
authors.affiliation: 1] Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA. [2] Department of Chemistry, Northwestern University, Evanston, Illinois, USA.
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rosenzweig
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002104:Cadmium / Q000737:chemistry* / Q000378:metabolism; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003035:Cobalt / Q000737:chemistry* / Q000378:metabolism; D049921:Cupriavidus / Q000737:chemistry / Q000201:enzymology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005288:Ferredoxins / Q000737:chemistry; D015870:Gene Expression; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D016366:Open Reading Frames; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D027682:Cation Transport Proteins; D005288:Ferredoxins; D011994:Recombinant Proteins; D002104:Cadmium; D003035:Cobalt; D000251:Adenosine Triphosphatases; D015032:Zinc