کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1316767 | 976479 | 2010 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mechanistic role of each metal ion in Streptomyces dinuclear aminopeptidase: Peptide hydrolysis and 7Â ÃÂ 1010-fold rate enhancement of phosphodiester hydrolysis
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی معدنی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Mechanistic role of each metal ion in Streptomyces dinuclear aminopeptidase: Peptide hydrolysis and 7Â ÃÂ 1010-fold rate enhancement of phosphodiester hydrolysis Mechanistic role of each metal ion in Streptomyces dinuclear aminopeptidase: Peptide hydrolysis and 7Â ÃÂ 1010-fold rate enhancement of phosphodiester hydrolysis](/preview/png/1316767.png)
چکیده انگلیسی
The dinuclear aminopeptidase from Streptomyces griseus (SgAP) and its metal derivatives catalyze the hydrolysis of the phosphoester bis(p-nitrophenyl) phosphate (BNPP) and the phosphonate ester p-nitrophenyl phenylphosphonate with extraordinary rate enhancements at pH 7.0 and 25 °C [A. Ercan, H. I. Park, L.-J. Ming, Biochemistry 45, (2006) 13779-13793.], reaching 6.7 billion-fold in terms of the first-order rate constant of the di-Co(II) derivative with respect to the autohydrolytic rates. Since phosphoesters are transition state-like inhibitors in peptide hydrolysis, their hydrolysis by SgAP is quite novel. Herein, we report the investigation of this proficient alternative catalysis of SgAP and the role of each metal ion in the dinuclear site toward peptide and BNPP hydrolysis. Mn(II) selectively binds to one of the dinuclear metal sites (M1), affording MnE-SgAP with an empty (E) second site for the binding of another metal (M2), including Mn(II), Co(II), Ni(II), Zn(II), and Cd(II). Peptide hydrolysis is controlled by M2, wherein the kcat values for the derivatives MnM2-SgAP are different yet similar between MnCo- and CoCo-SgAP and pairs of other metal derivatives. On the other hand, BNPP hydrolysis is affected by metals in both sites. Thus, the two hydrolytic catalyses must follow different mechanisms. Based on crystal structures, docking, and the results presented herein, the M1 site is close to the hydrophobic specific site and the M2 site is next to Tyr246 that is H-bonded to a coordinated nucleophilic water molecule in peptide hydrolysis; whereas a coordinated water molecule on M1 becomes available as the nucleophile in phosphodiester hydrolysis.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Inorganic Biochemistry - Volume 104, Issue 1, January 2010, Pages 19-29
Journal: Journal of Inorganic Biochemistry - Volume 104, Issue 1, January 2010, Pages 19-29
نویسندگان
Altan Ercan, William M. Tay, Steven H. Grossman, Li-June Ming,