Molecular interactions in ribose transport: The binding protein module symmetrically associates with the homodimeric membrane transporter

Yongkyu Park, Young Jin Cho, Taeho Ahn, Chankyu Park

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

The Escherichia coli high-affinity ribose transporter is composed of the periplasmic ribose-binding protein (RBP or RbsB), the membrane component (RbsC) and the ATP-binding protein (RbsA). In order to dissect the molecular interactions initiating the transport process, RbsC suppressors for transport-defective rbsB mutations were isolated. These suppressors are localized in two regions of RbsC, which are allele-specific to N- or C-terninal domain mutations of RBP, suggesting that there are two distinct regions of RbsC, each interacting with one of the two domains of RBP. To demonstrate that these two regions provide a homodimeric binding surface for RBP we constructed a dimeric rbsC in which two genes are joined tandemly from head to tail with the addition of a linker. The dimeric RbsC protein is stable and functional in growth and ribose uptake. By exploiting the allele specificity between the domain-specific mutations and their suppressors, we generated all mutation-suppressor combinations in a single rbsB plus the dimeric rbsC genes. Their phenotypes are consistent with the proposal that the binding protein module interacts symmetrically with homodimeric RbsC. The mode of association proposed here for the ribose transport components could be extended to other ABC transporters with similar structural organizations.

Original languageEnglish (US)
Pages (from-to)4149-4156
Number of pages8
JournalEMBO Journal
Volume18
Issue number15
DOIs
StatePublished - Aug 2 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology

Keywords

  • ABC transporter
  • Integral membrane protein
  • Ribose-binding protein
  • Transport mechanism

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