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Research GBB Membrane Enzymology

Bacterial vitamin transport


Bacterial vitamin transport (Prof. Dr. D.J. Slotboom)

Many prokaryotes can take up vitamins (such as thiamin, riboflavin, biotin, niacin, etc) by protein complexes that shares resemblance with ATP Binding Cassette (ABC) transporters. These transporters are called Energy Coupling Factor (ECF) transporters and consist of a conserved tripartite complex containing two identical or homologous nucleotide binding proteins/domains (EcfA and EcfA′) and a small ( 30 kDa) integral membrane protein EcfT. In contrast to ordinary bacterial ABC transporters for substrate uptake, ECF transporters do not employ soluble Substrate Binding Proteins (SBPs) but instead use small ( 20 kDa) integral membrane proteins with five to six predicted transmembrane helices for substrate recognition and binding. A plethora of such binding proteins have been found encoded in the genomes of prokaryotes, each specific for a different substrate. Different substrate specificity proteins can interact with the same tripartite ECF protein complexes, forming a complete transport system likely to resemble the basic architecture of an ABC transporter, consisting of two transmembrane domains and two nucleotide binding domains, but lacking the soluble SBPs.




  1. Erkens, G. B. , and Slotboom, D. J. (2010) Biochemical Characterization of ThiT from Lactococcus lactis: A Thiamin Transporter with Picomolar Substrate Binding Affinity. Biochemistry 49 (14), 3203–3212
  2. Eudes, A. , Erkens, G. B. , Slotboom, D. J. , Rodionov, D. A. , Naponelli, V. , and Hanson, A. D. (2008) Identification of genes encoding the folate- and thiamine-binding membrane proteins in firmicutes. J. Bacteriol. 190, 75917594
  3. Rodionov, D. A. , Hebbeln, P. , Eudes, A. , ter, B. J. , Rodionova, I. A. , Erkens, G. B. , Slotboom, D. J. , Gelfand, M. S. , Osterman, A. L. , Hanson, A. D. , and Eitinger, T. (2009) A novel class of modular transporters for vitamins in prokaryotes. J. Bacteriol. 191, 4251
  4. Duurkens, R. H. , Tol, M. B. , Geertsma, E. R. , Permentier, H. P. , and Slotboom, D. J. (2007) Flavin binding to the high affinity riboflavin transporter RibU J. Biol. Chem. 282, 1038010386
Last modified:03 October 2012 12.04 p.m.