完整後設資料紀錄
DC 欄位語言
dc.contributor.authorHsieh, Yin-Chengen_US
dc.contributor.authorWu, Yue-Jinen_US
dc.contributor.authorChiang, Tzu-Yingen_US
dc.contributor.authorKuo, Chueh-Yuanen_US
dc.contributor.authorShrestha, Keshab Lalen_US
dc.contributor.authorChao, Cheng-Fuen_US
dc.contributor.authorHuang, Yen-Chiehen_US
dc.contributor.authorChuankhayan, Phimonphanen_US
dc.contributor.authorWu, Wen-Gueyen_US
dc.contributor.authorLi, Yaw-Kuenen_US
dc.contributor.authorChen, Chun-Jungen_US
dc.date.accessioned2014-12-08T15:48:06Z-
dc.date.available2014-12-08T15:48:06Z-
dc.date.issued2010-10-08en_US
dc.identifier.issn0021-9258en_US
dc.identifier.urihttp://dx.doi.org/10.1074/jbc.M110.149310en_US
dc.identifier.urihttp://hdl.handle.net/11536/32081-
dc.description.abstractChitinases hydrolyze chitin, an insoluble linear polymer of N-acetyl-D-glucosamine (NAG)(n), into nutrient sources. Bacillus cereus NCTU2 chitinase (ChiNCTU2) predominantly produces chitobioses and belongs to glycoside hydrolase family 18. The crystal structure of wild-type ChiNCTU2 comprises only a catalytic domain, unlike other chitinases that are equipped with additional chitin binding and insertion domains to bind substrates into the active site. Lacking chitin binding and chitin insertion domains, ChiNCTU2 utilizes two dynamic loops (Gly-67-Thr-69 and Ile-106-Val-112) to interact with (NAG)(n), generating novel substrate binding and distortion for catalysis. Gln-109 is crucial for direct binding with substrates, leading to conformational changes of two loops with a maximum shift of similar to 4.6 angstrom along the binding cleft. The structures of E145Q, E145Q/Y227F, and E145G/Y227F mutants complexed with (NAG)(n) reveal (NAG)(2), (NAG)(2), and (NAG)(4) in the active site, respectively, implying various stages of reaction: before hydrolysis, E145G/Y227F with (NAG)(4); in an intermediate state, E145Q/Y227F with a boat-form NAG at the -1 subsite, -1-(NAG); after hydrolysis, E145Q with a chair form -1-(NAG). Several residues were confirmed to play catalytic roles: Glu-145 in cleavage of the glycosidic bond between -1-(NAG) and -1-(NAG); Tyr-227 in the conformational change of -1-(NAG); Asp-143 and Gln-225 in stabilizing the conformation of -1-(NAG). Additionally, Glu-190 acts in the process of product release, and Tyr-193 coordinates with water for catalysis. Residues Asp-143, E145Q, Glu190, and Tyr-193 exhibit multiple conformations for functions. The inhibitors zinc ions and cyclo-(L-His-L-Pro) are located at various positions and confirm the catalytic-site topology. Together with kinetics analyses of related mutants, the structures of ChiNCTU2 and its mutant complexes with (NAG)(n) provide new insights into its substrate binding and the mechanistic action.en_US
dc.language.isoen_USen_US
dc.titleCrystal Structures of Bacillus cereus NCTU2 Chitinase Complexes with Chitooligomers Reveal Novel Substrate Binding for Catalysis A CHITINASE WITHOUT CHITIN BINDING AND INSERTION DOMAINSen_US
dc.typeArticleen_US
dc.identifier.doi10.1074/jbc.M110.149310en_US
dc.identifier.journalJOURNAL OF BIOLOGICAL CHEMISTRYen_US
dc.citation.volume285en_US
dc.citation.issue41en_US
dc.citation.spage31603en_US
dc.citation.epage31615en_US
dc.contributor.department應用化學系zh_TW
dc.contributor.departmentDepartment of Applied Chemistryen_US
顯示於類別:期刊論文


文件中的檔案:

  1. 000282764600054.pdf

若為 zip 檔案,請下載檔案解壓縮後,用瀏覽器開啟資料夾中的 index.html 瀏覽全文。