Functions of family-22 carbohydrate-binding modules in Clostridium josui Xyn10A.
Clostridium josui xylanase Xyn10A is a modular enzyme comprising two family-22 carbohydrate-binding modules (CBMs), a family-10 catalytic module (CM), a family-9 CBM, and two S-layer homologous modules, consecutively from the N-terminus. To study the functions of the family-22 CBMs, truncated derivatives of Xyn10A were constructed: a recombinant CM polypeptide (rCM), a family-22 CBM polypeptide (rCBM), and a polypeptide composed of the family-22 CBMs and CM (rCBM-CM). Recombinant proteins were characterized by enzyme and binding assays. rCBM-CM showed the highest activity toward xylan and weak activity toward some polysaccharides such as barley beta-glucan and carboxymethyl-cellulose. Although rCBM showed an affinity for insoluble and soluble xylan as well as barley beta-glucan and Avicel in qualitative binding assays, removal of the CBMs negligibly affected the catalytic activity and thermostability of the CM.
Ali
Ehsan
E
Faculty of Bioresources, Mie University, Tsu, Japan.
Araki
Rie
R
Zhao
Guangshan
G
Sakka
Makiko
M
Karita
Shuichi
S
Kimura
Tetsuya
T
Sakka
Kazuo
K
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002384:Catalysis; D002482:Cellulose / Q000378:metabolism; D003013:Clostridium / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D001467:Hordeum / Q000737:chemistry; D010957:Plasmids / Q000235:genetics; D011134:Polysaccharides / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013816:Thermodynamics; D047071:beta-Glucans / Q000378:metabolism
D001426:Bacterial Proteins; D011134:Polysaccharides; D011994:Recombinant Proteins; D047071:beta-Glucans; D002482:Cellulose