Enhancing the activity of Bacillus circulans xylanase by modulating the flexibility of the hinge region.
Enzymes undergo multiple conformational changes in solution, and these dynamics are considered to play a critical role in enzyme activity. Hinge-bending motions, resulting from reciprocal movements of dynamical quasi-rigid bodies, are thought to be related to turnover rate and are affected by the physical properties of the hinge regions. In this study, hinge identification and flexibility modification of the regions by mutagenesis were conducted to explore the relationship between hinge flexibility and catalytic activity. Bacillus circulans xylanase was selected for the identification and mutation of the hinge regions. As a result, turnover rate (V(max)) was improved approximately twofold in mutants that have more rigid hinge structure, despite the decrease in K(m) and V(max)/K(m). This result indicates that the rigidly mutated hinge has positive effects on B. circulans xylanase activity.
Graduate Program of Bioengineering, Seoul National University, Seoul, 151-742, Republic of Korea.
Fukura
F
Kazuyo
So Yeon
SY
Hong
Young Joo
YJ
Yeon
Jeong Chan
JC
Joo
Young Je
YJ
Yoo
D000596:Amino Acids / Q000737:chemistry; D001407:Bacillus / Q000201:enzymology*; D001696:Biomechanical Phenomena; D017931:DNA Primers / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation
D000596:Amino Acids; D017931:DNA Primers; D043364:Endo-1,4-beta Xylanases