tailieunhanh - Báo cáo khoa học: Crystal structures of open and closed forms of cyclo⁄maltodextrin-binding protein

The crystal structures ofThermoactinomyces vulgariscyclo⁄maltodextrin-binding protein (TvuCMBP) complexed with a-cyclodextrin (a-CD), b-cyclodextrin (b-CD) and maltotetraose (G4) have been determined. A common functional conformational change among all solute-binding pro-teins involves switching from an open form to a closed form, which facili-tates transporter binding. | Crystal structures of open and closed forms of cyclo maltodextrin-binding protein Naoki Matsumoto1 Mitsugu Yamada2 Yuma Kurakata1 Hiromi Yoshida2 3 Shigehiro Kamitori2 3 Atsushi Nishikawa1 and Takashi Tonozuka1 1 Department of Applied BiologicalScience Tokyo University of Agriculture and Technology Japan 2 Graduate Schoolof Medicine Kagawa University Japan 3 Life Science Research Center Kagawa University Japan Keywords crystal structure cyclodextrin maltodextrin-binding protein sugar transporter Thermoactinomyces vulgaris Correspondence T. Tonozuka Department of Applied BiologicalScience Tokyo University of Agriculture and Technology 3-5-8 Saiwai-cho Fuchu Tokyo 183-8509 Japan Fax 81 42 3675705 Tel 81 42 3675702 E-mail tonozuka@ Present address Research Unit for Quantum Beam Life Science Initiative Japan Atomic Energy Agency 1233 Watanuki Takasaki Gunma 370-1292 Japan Database The coordinates and structure factors of TvuCMBP-a-CD TvuCMBP-b-CD and TvuCMBP-G4 have been deposited in the Protein Data Bank under the accession codes 2ZYM 2ZYN and 2ZYO respectively. The revised coordinate of TvuCMBP-y-CD has been deposited in the Protein Data Bank under the accession code 2ZYK The crystal structures of Thermoactinomyces vulgaris cyclo maltodextrin-binding protein TvuCMBP complexed with a-cyclodextrin a-CD b-cyclodextrin b-CD and maltotetraose G4 have been determined. A common functional conformational change among all solute-binding proteins involves switching from an open form to a closed form which facilitates transporter binding. Escherichia coli maltodextrin-binding protein EcoMBP which is structurally homologous to TvuCMBP has been determined to adopt the open form when complexed with b-CD and the closed form when bound to G4. Here we show that unlike EcoMBP TvuCMBP-a-CD and TvuCMBP-b-CD adopt the closed form when complexed whereas TvuCMBP-G4 adopts the open form. Only two glucose residues are evident in the TvuCMBP-G4 structure and these bind to the .