Download MendeleyChitin Translocation Is Functionally Coupled with Synthesis in Chitin Synthase.
Niu, S., Qi, L., Zhang, X., He, D., Li, P., Wang, H., Bi, Y.(2024) Int J Mol Sci 25
- PubMed: 39519219
- DOI: https://doi.org/10.3390/ijms252111667
- Primary Citation of Related Structures:
8K52, 8Z0O - PubMed Abstract:
Chitin, an extracellular polysaccharide, is synthesized by membrane-embedded chitin synthase (CHS) utilizing intracellular substrates. The mechanism of the translocation of synthesized chitin across the membrane to extracellular locations remains unresolved. We prove that the chitin synthase from Phytophthora sojae ( Ps CHS) is a processive glycosyltransferase, which can rapidly produce and tightly bind with the highly polymerized chitin. We further demonstrate that Ps CHS is a bifunctional enzyme, which is necessary and sufficient to translocate the synthesized chitin. Ps CHS was purified and then reconstituted into proteoliposomes (PLs). The nascent chitin is generated and protected from chitinase degradation unless detergent solubilizes the PLs, showing that Ps CHS translocates the newly produced chitin into the lumen of the PLs. We also attempted to resolve the Ps CHS structure of the synthesized chitin-bound state, although it was not successful; the obtained high-resolution structure of the UDP/Mn 2+ -bound state could still assist in describing the characterization of the Ps CHS's transmembrane channel. Consistently, we demonstrate that Ps CHS is indispensable and capable of translocating chitin in a process that is tightly coupled to chitin synthesis.
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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