کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2053360 | 1074273 | 2005 | 7 صفحه PDF | دانلود رایگان |
Cellobiohydrolase A (CbhA) from Clostridium thermocellum is composed of an N-terminal carbohydrate-binding domain 4 (CBD4), an immunoglobulin-like domain (Ig), a glycoside hydrolase 9 (GH9), X11 and X12 domains, a CBD3, and a dockerin domain. All domains, except the Ig, bind Ca2+. The following constructs were made: X12, X11X12, CBD3, X11X12-CBD3, Ig, GH9, Ig-GH9, Ig-GH9-X11X12, and Ig-GH9-X11X12-CBD3. Interactions between domains in (1) buffer, (2) with Ca2+, or (3) ethylenediaminetetraacetic acid (EDTA) were studied by differential scanning calorimetry. Thermal unfoldings of all constructs were irreversible. Calcium increased Td and cooperativity of unfolding. Multi-domain constructs exhibited more cooperative unfolding in buffer and in the presence of EDTA than did individual domains. They denatured by mechanism simpler than expected from their modular architecture. The results indicate that domain coupling in thermophilic proteins constitutes a significant stabilizing factor.
Journal: FEBS Letters - Volume 579, Issue 20, 15 August 2005, Pages 4367–4373