کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
442925 692434 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Structural and mechanistic insights into a novel non-competitive Kunitz trypsin inhibitor from Adenanthera pavonina L. seeds with double activity toward serine- and cysteine-proteinases
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Structural and mechanistic insights into a novel non-competitive Kunitz trypsin inhibitor from Adenanthera pavonina L. seeds with double activity toward serine- and cysteine-proteinases
چکیده انگلیسی

Kunitz proteinase inhibitors are widely distributed in legume seeds, and some of them have the ability to inhibit two different classes of enzymes. In this report, novel insights into three-dimensional structure and action mechanism of ApKTI, an Adenanthera pavonina Kunitz trypsin inhibitor, were provided to shed some light on an unconventional non-competitive activity against trypsin and papain. Firstly, ApKTI was purified by two tandem-size molecular exclusion chromatography high resolutions, Sephacryl S-100 and Superose 12 10/300 GL. Purified ApTKI showed molecular mass of 22 kDa and higher affinity against trypsin in comparison to papain, while the bifunctional inhibitor presented lower inhibitory activity. Moreover, in vitro assays showed that ApKTI has two independent interaction sites, permitting simultaneous inhibition to both enzymes. Theoretical three-dimensional structures of ApTKI complexed to both target proteinases were constructed in order to determine interaction mode by using Modeller v9.6. Since the structure of no non-competitive Kunitz inhibitor has been elucidated, ApTKI-trypsin and ApTKI-papain docking were carried out using Hex v5.1. In silico experiments showed that the opposite inhibitor loop interacts with adjacent sites of trypsin (Arg64, Ser107, Arg88 and Lys108) and papain (Gln51, Asp172 and Arg173), probably forming a ternary complex. Unusual residue substitutions at the proposed interface can explain the relative rarity of twin trypsin/papain inhibition. The predicted non-coincidence of trypsin and papain binding sites is completely different from that of previously proposed inhibitors, adding more information about mechanisms of non-competitive plant proteinase inhibitors.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Graphics and Modelling - Volume 29, Issue 2, September 2010, Pages 148–156
نویسندگان
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