The importance of being knotted: effects of the C‐terminal knot structure on enzymatic and mechanical properties of bovine carbonic anhydrase II 1

FEBS Letters

Alam, Mohammad Taufiq¹  Carlsson, Uno²  Ikai, Atsushi¹  Yamada, Takafumi¹ 

[1] Laboratory of Biodynamics, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 Japan;Department of Chemistry, Linköping University, SE-581 83 Linköping, Sweden

关键词: Atomic force microscope;    Carbonic anhydrase II;    Mechanical unfolding;    Conformer;    Knot structure;    AFM;    atomic force microscope;    F–E;    force–extension;    BCAII;    bovine carbonic anhydrase II;    HCAII;    human carbonic anhydrase II;    CD;    circular dichroism;   

DOI  :  10.1016/S0014-5793(02)02693-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In order to better understand the contribution of the knotted folding pattern to the enzymatic and mechanical properties of carbonic anhydrases, we replaced Gln-253 of bovine carbonic anhydrase II with Cys, which allowed us to measure the mechanical strength of the protein against tensile deformation by avoiding knot tightening. The expressed protein, to our surprise, turned out to contain two conformational isomers, one capable of binding an enzymatic inhibitor and the other not, which led to their separation through affinity chromatography. In near- and far-UV circular dichroism and fluorescence spectra, the separated conformers were very similar to each other and to the wild-type enzyme, indicating that they both had native-like conformations. We describe new evidence which supports the notion that the difference between the two conformers is likely to be related to the completeness of the C-terminal knot formation.

【 授权许可】

Unknown