Chemical modification of lysine side chains of cyclodextrin glycosyltransferase from Thermoanaerobacter causes a shift from cyclodextrin glycosyltransferase to α‐amylase specificity

FEBS Letters

Andersen, Carsten¹  Pedersen, Sven¹  Ballesteros, Antonio²  Plou, Francisco J²  Martı́n, M.Teresa²  Alcalde, Miguel² 

[1] Novo Nordisk A/S, Novó Allé, 2880 Bagsvaerd, Denmark;Departamento de Biocatálisis. Instituto de Catálisis, CSIC, Campus Universidad Autónoma, 28049 Madrid, Spain

关键词: Cyclodextrin glycosyltransferase;    α-Amylase;    Cyclization;    Coupling;    Disproportionation;    Hydrolysis;    Cyclodextrin;    Chemical modification;    CDs;    cyclodextrins;    CGTases;    cyclodextrin glycosyltransferases;    Tabium;    Thermoanaerobacterium thermosulfurigenes EM1;   

DOI  :  10.1016/S0014-5793(99)00134-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

cyclodextrin glycosyltransferases and α-amylases are two groups of enzymes with related secondary structures. However, cyclodextrin glycosyltransferases display transferase activities not present in α-amylases, probably derived from the existence of two more domains and different amino acid sequences. The hydrolytic activity of cyclodextrin glycosyltransferases is generally quite low, except for two cyclodextrin glycosyltransferases from termophiles. In this work, we have carried out the chemical modification (with acetic anhydride) of the amino groups of cyclodextrin glycosyltransferase from Thermoanaerobacter to assess their contributions to protein function. The acetylated cyclodextrin glycosyltransferase showed a significant reduction of its cyclization, coupling and disproportionation activities. Surprisingly, the hydrolytic (saccharifying) activity was slightly enhanced. These results suggest the participation of one or more lysine side chains in the interactions contributing to the transferase activity, either in any of the S_n subsites or in the acceptor binding site.

【 授权许可】

Unknown