کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6491543 | 43412 | 2014 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structural basis of a mutant Y195I α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Structural basis of a mutant Y195I α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin Structural basis of a mutant Y195I α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin](/preview/png/6491543.png)
چکیده انگلیسی
Cyclodextrin glycosyltransferase (EC 2.4.1.19) (CGTase) is an extracellular bacterial enzyme which has the unique capability of forming cyclodextrins from starch. Our previous investigation revealed that a mutant Y195I α-CGTase drastically altered the cyclodextrin specificity by switching toward the synthesis of both β- and γ-CDs (Xie et al., 2013a, Xie et al., 2013b). In this study, we determined one X-ray structure of the mutant Y195I α-CGTase at 2.3 Ã
. The overall structure was similar to that of the typical β-CGTase from Bacillus circulans 251, with minor difference in flexible domains since they showed about 70% homogeneity of amino acid sequences. The central site with isoleucine tended to be more flexible than tyrosine thus made the sugar chain, during the cyclization process, form a larger cyclodextrin like β- and γ-CDs surrounding the central site instead of α-CD. Superposition of the structure of Y195I α-CGTase with those of β-CGTase and γ-CGTase showed that residues Lys232, Lys89 and Arg177 at subsites +2, â3 and â7 could form smaller substrate binding cavity. In summary, the crystal structure revealed that moderate increase of mobility of the central site resulted in the switched product specificity from α-CD to β- and γ-CDs of the mutant Y195I α-CGTase. The space differences alongside the active domain may be another factor that impacts the product specificity of the CGTase.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Biotechnology - Volumes 182â183, 20 Julyâ10 August 2014, Pages 92-96
Journal: Journal of Biotechnology - Volumes 182â183, 20 Julyâ10 August 2014, Pages 92-96
نویسندگان
Ting Xie, Yanjie Hou, Defeng Li, Yang Yue, Shijun Qian, Yapeng Chao,