title: A novel three-component system-based regulatory model for D-xylose sensing and transport in Clostridium beijerinckii.
abstract: D-Xylose is the most abundant fermentable pentose in nature and can serve as a carbon source for many bacterial species. Since D-xylose constitutes the major component of hemicellulose, its metabolism is important for lignocellulosic biomass utilization. Here, we report a six-protein module for D-xylose signaling, uptake and regulation in solvent-producing Clostridium beijerinckii. This module consists of a novel 'three-component system' (a putative periplasmic ABC transporter substrate-binding protein XylFII and a two-component system LytS/YesN) and an ABC-type D-xylose transporter XylFGH. Interestingly, we demonstrate that, although XylFII harbors a transmembrane domain, it is not involved in D-xylose transport. Instead, XylFII acts as a signal sensor to assist the response of LytS/YesN to extracellular D-xylose, thus enabling LytS/YesN to directly activate the transcription of the adjacent xylFGH genes and thereby promote the uptake of D-xylose. To our knowledge, XylFII is a novel single transmembrane sensor that assists two-component system to respond to extracellular sugar molecules. Also of significance, this 'three-component system' is widely distributed in Firmicutes, indicating that it may play a broad role in this bacterial phylum. The results reported here provide new insights into the regulatory mechanism of D-xylose sensing and transport in bacteria.
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Sun
authors.forename: Yixiong
authors.initials: Y
authors.lastname: Chen
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Yang
authors.initials: Y
authors.lastname: Gu
authors.forename: Weihong
authors.initials: W
authors.lastname: Jiang
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D046970:Clostridium beijerinckii / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D011506:Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment; D015398:Signal Transduction; D014994:Xylose / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D011506:Proteins; D014994:Xylose