کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1178961 962744 2009 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Molecular determinants of substrate and inhibitor specificities of the Penicillium griseofulvum family 11 xylanases
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Molecular determinants of substrate and inhibitor specificities of the Penicillium griseofulvum family 11 xylanases
چکیده انگلیسی

Penicillium griseofulvum possesses two endo-(1,4)-β-xylanase genes, PgXynA and PgXynB, belonging to family 11 glycoside hydrolases. The enzymes share 69% identity, a similar hydrolysis profile i.e. the predominant production of xylobiose and xylotriose as end products from wheat arabinoxylan and a specificity region of six potential xylose subsites, but differ in terms of catalytic efficiency which can be explained by subtle structural differences in the positioning of xylohexaose in the PgXynB model. Site-directed mutagenesis of the “thumb” region revealed structural basis of PgXynB substrate and inhibitor specificities. We produced variants displaying increased catalytic efficiency towards wheat arabinoxylan and xylo-oligosaccharides and identified specific determinants in PgXynB “thumb” region responsible for resistance to the wheat xylanase inhibitor XIP-I. Based on kinetic analysis and homology modeling, we suggested that Pro130PgXynB, Lys131PgXynB and Lys132PgXynB hamper flexibility of the loop forming the “thumb” and interfere by steric hindrance with the inhibitor.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1794, Issue 3, March 2009, Pages 438–445
نویسندگان
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