The Journal of Membrane Biology

, Volume 156 , Issue 2 , pp 99 –103

A Novel Family of Ubiquitous Heavy Metal Ion Transport Proteins

  • I.T.  Paulsen
  • M.H.  Saier, Jr.

DOI: 10.1007/s002329900192

Cite this article as:
Paulsen, I. & Saier, Jr., M. J. Membrane Biol. (1997) 156: 99. doi:10.1007/s002329900192


We describe a novel diverse family of metal ion transporter (CDF) proteins (the cation diffusion facilitator (CDF) family) with members occurring in both prokaryotes and eukaryotes. Thirteen sequenced protein members of the CDF family have been identified, several of which have been shown to transport cobalt, cadmium and/or zinc. All members of the CDF family possess six putative transmembrane spanners with strongest conservation in the four N-terminal spanners, and on the basis of the analyses, we present a unified structural model. Members of the family are shown to exhibit an unusual degree of size variation, sequence divergence, and differences in cell localization and polarity. The phylogenetic tree for the CDF family reveals that prokaryotic and eukaryotic proteins cluster separately. It allows functional predictions for some uncharacterized members of this family. A signature sequence specific for the CDF family is derived.

Key words: Transport — Membrane proteins — Cobalt — Cadmium — Zinc — Uptake — Efflux — pmf — Phylogenetic analysis 

Copyright information

© 1997 Springer-Verlag New York Inc.

Authors and Affiliations

  • I.T.  Paulsen
    • 1
  • M.H.  Saier, Jr.
    • 1
  1. 1.Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USAUS

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