LXYL-P1-2 is one of the few xylosidases that efficiently catalyze the reaction from 7-βxylosyl-10-deacetyltaxol (XDT) to 10-deacetyltaxol (DT), and is a potential enzyme used in Taxol industrial production. Here we report the crystal structure of LXYL-P1-2 and its XDT binding complex. These structures reveal an enzyme/product complex with the sugar conformation different from the enzyme/substrate complex reported previously in GH3 enzymes, even in the whole glycohydrolases family. In addition, the DT binding pocket is identified as the structural basis for the substrate specificity. Further structure analysis reveals common features in LXYL-P1-2 and Taxol binding protein tubulin, which might provide useful information for designing new Taxol carrier proteins for drug delivery.
Stress granules (SGs) are cytoplasmic biomolecular condensates containing proteins and RNAs in response to stress. Ras-GTPase–activating protein binding protein 1 (G3BP1) is a core SG protein. Caprin-1 and ubiquitin specific peptidase 10 (USP10) interact with G3BP1, facilitating and suppressing SG formation, respectively. The crystal structures of the nuclear transport factor 2-like (NTF2L) domain of G3BP1 in complex with the G3BP1-interacting motif (GIM) of Caprin-1 and USP10 show that both GIMs bind to the same hydrophobic pocket of G3BP1. Moreover, both GIMs suppressed the liquid–liquid phase separation (LLPS) of G3BP1, suggesting that Caprin-1 likely facilitates SG formation via other mechanisms. Thus, we dissected various domains of Caprin-1 and investigated their role in LLPS in vitro and SG formation in cells. The C-terminal domain of Caprin-1 underwent spontaneous LLPS, whereas the N-terminal domain and GIM of Caprin-1 suppressed LLPS of G3BP1. The opposing effect of the N- and C-terminal domains of Caprin-1 on SG formation were demonstrated in cells with or without the endogenous Caprin-1. We propose that the N- and C-terminal domains of Caprin-1 regulate SG formation in a “yin and yang” fashion, mediating the dynamic and reversible assembly of SGs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.