The substrate-binding protein in bacterial ABC transporters: Dissecting roles in the evolution of substrate specificity

Abbas Maqbool, Richard S P Horler, Axel Muller, Anthony J. Wilkinson, Keith S. Wilson, Gavin H. Thomas*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


ATP-binding cassette (ABC) transporters, although being ubiquitous in biology, often feature a subunit that is limited primarily to bacteria and archaea. This subunit, the substrate-binding protein (SBP), is a key determinant of the substrate specificity and high affinity of ABC uptake systems in these organisms. Most prokaryotes have many SBP-dependent ABC transporters that recognize a broad range of ligands from metal ions to amino acids, sugars and peptides. Herein, we review the structure and function of a number of more unusual SBPs, including an ABC transporter involved in the transport of rare furanose forms of sugars and an SBP that has evolved to specifically recognize the bacterial cell wall-derived murein tripeptide (Mtp). Both these examples illustrate that subtle changes in binding-site architecture, including changes in side chains not directly involved in ligand co-ordination, can result in significant alteration of substrate range in novel and unpredictable ways.

Original languageEnglish
Pages (from-to)1011-1017
Number of pages7
JournalBiochemical Society transactions
Issue number5
Publication statusPublished - 9 Oct 2015


  • Adenosine 5′-triphosphate-binding cassette (ABC) transporter
  • Evolution
  • Substrate specificity
  • Substratebinding protein (SBP)

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