Biologia, Bratislava, 57/Suppl. 11: 87-92, 2002.
ISSN 0006-3088 (Biologia).
N- and C-terminal region mediated oligomerization of the cyclodextrin-/pullulan degrading enzymes.
Kwan Hwa Park1*, Hee Seob Lee1, Tae Jip Kim1, Kyung Ah Cheong1, Van Dao Nguyen 1, Mee Jung Min1, Hee Yeon Cho1, Young Wan Kim1, Cheon Seok Park2, Byung Ha Oh3 & Jung Wan Kim4
1 Research Center for New Bio-Materials in Agriculture and Department of Food Science and Food Technology, School of Agricultural Biotechnology, Seoul National University, Suwon, 441-744, Korea; tel.: ++ 82 31 290 2582, fax: ++ 82 31 294 1336, e-mail: email@example.com
2 Department of Food Science and Technology, Kyunghee University, Yongin, 449-701, Korea
3 Department of Life Science, and Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790-784, Korea
4 Department of Biology, University of Incheon, Incheon, 402-749, Korea
Cyclodextrin-/pullulan (CD-/PUL)-degrading enzymes catalyze hydrolysis and transglycosylation reactions of various substrates such as starch, cyclodextrin, and pullulan. Recently, these enzymes have been proved to exist in equilibria of monomer-dimer and monomer-dimer-tetramer or -dodecamer. Two regions in the CD-/PUL-degrading enzymes were identified as being involved in oligomerization; one is close to the N-terminal and the other located near the C-terminal region. The three-dimensional structure and deletion mutagenesis analyses revealed that the N-terminal region affected the dimerization properties of monomeric Thermus maltogenic amylase (ThMA). On the other hand, both the N- and C-terminal regions were involved in dodecamerization of cyclodextrinase I-5 (CDase I-5) dimeric units. Oligomerization of these enzymes was also modulated by salt concentration and pH of the reaction buffer.
Key words: cyclodextrin degrading enzyme, dimer, dodecamer, oligomeric state.