Bacteria recepose important five-carbon sugars- wood sugars and regulate the molecular mechanisms of their absorption and utilization.

On July 18, the Proceedings of the National Academy of Sciences (PNAS) published online a research paper by Zhang Peng of the Institute of Plant Physiology and Ecology of the Shanghai Institute of Life Sciences of the Chinese Academy of Sciences and Jiang Weihong Research Group, entitled Molecular mechanism of environmental d-xylose perception by a XylFII-LytS complex in bly.
This study reveals the molecular mechanism of bacteria to sense important xylitose-xylitose and regulate its absorption and utilization by analyzing the crystal structure of XylFII-LytS, a two-component regulatory complex responsible for sensing xylitose signals on the Clostridium difficion membrane, combined with physiological, biochemical and genetic analysis.
is the most important sugar group in the raw materials of wood fiber such as straw, besides glucose, and is the most abundant five-carbon sugar in nature.
how to make them efficient for microorganisms to use and synthesize useful chemicals has been a concern.
solvent Clostridium difficori is an important industrial microorganism that can produce bulk chemicals and biofuels such as butanol, ethanol and acetone through fermentation.
although the bacteria can use a certain amount of wood sugar, but inefficient.
In a previous study, Jiang Weihong's team found a conservative two-component protein complex, XylFII-LytS, on the endometrium of Clostridium difficid cells to sense the xylFII-LytS in the environment and regulate its use.
is an important link in the metabolic process of wood sugar, but its molecular mechanism is little known.
In this work, under the guidance of researchers Zhang Peng and Jiang Weihong, Li Jianxuan and others analyzed the three-dimensional structure of XylFII-LytS peri-space domain (XylFII-LytSN) in the binding and non-binding xylitol state.
by comparing and analyzing these structures, it is found that xylfii molecules can be specifically combined on XylFII proteins and induce their N-end and C-end domains to change from open to closed.
this kind of structure change and then induces two XylFII-LytSN decathons to form heterogenous tyrheaths and become the molecular framework conducive to signal transmission.
Therefore, it is inferred that XylFII-LytS heterogenous tetum, which binds to two molecules of xylfixaccharide, is its active form, and that xylose signals are transmitted to the membrane through the two-molecule histamine kinase LytS in this tetum, and to improve the use of xylFGH by activating the response regulatory protein to initiate the expression of xylFGH, the xylFGH.
further, the team used physiological, biochemical and genetic methods to confirm this inference by targeting the key amino acid residues of the protein for the purpose of the mutation, combined with experiments and physiological analysis in Clostridium difficori.
the study reveals the inner molecular mechanism of bacterial lysaccharide signaling and regulation, which provides new ideas and basis for the utilization of this important five-carbon sugar and the molecular transformation of industrial strains.
research has been funded by the Fund Committee and the Chinese Academy of Sciences.
data collection has been supported and assisted by Shanghai Light Source 17U Line Station and National Protein Center (Shanghai) Facility 19U1/U2 Line Station.
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