Properties of four C-terminal carbohydrate-binding modules (CBM4) of laminarinase Lic16A of Clostridium thermocellum

Autor: Dvortsov Ia, Velikodvorskaia Ga, N. A. Lunina, Vladimir V. Zverlov
Rok vydání: 2012
Předmět:
Zdroj: Molecular Biology. 46:817-822
ISSN: 1608-3245
0026-8933
DOI: 10.1134/s0026893312060039
Popis: At the C-terminus of multimodular laminarinase Lic16A from Clostridium thermocellum, four carbohydrate-binding modules (CBM) of family 4 were found. Isolated CBM4_1, CBM4_2, CBM4_3, and CBM4_4 modules and the CBM4_(1-4) tandem were obtained. None of the recombinant proteins had the affinity to soluble β-1,3-1,4-glucans, laminarin and lichenan, the main specific Lic16A substrates. All modules, except CBM4_4, had the ability to bind bacterial crystalline cellulose, which is atypical of family-4 CBMs. All CBMs 4 of Lic16A had an affinity to xylan, chitin, yeast cell wall β-glucan, and avicel, while CBM4_3 and CBM4_4 also had an affinity to chitosan. The CBM4_(1-4) tandem had the highest affinity to the β-glucan, avicel, and pustulan of the yeast cell wall. The CBM4_(1-4) binding constants for these substrates were approximately 100-fold higher than those of its individual modules, which suggests synergy in the process of absorbing these polysaccharides. This finding helps to explain the evolutionary process of CBM multiplication.
Databáze: OpenAIRE
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