کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1356340 | 981110 | 2006 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A semiempirical study of acetylcholine hydrolysis catalyzed by Drosophila melanogaster acetylcholinesterase
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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![عکس صفحه اول مقاله: A semiempirical study of acetylcholine hydrolysis catalyzed by Drosophila melanogaster acetylcholinesterase A semiempirical study of acetylcholine hydrolysis catalyzed by Drosophila melanogaster acetylcholinesterase](/preview/png/1356340.png)
چکیده انگلیسی
The enzymatic mechanism of acetylcholine hydrolysis was evaluated by semiempirical molecular orbital calculations with a model constructed with the coordinates of sixteen amino acids and four water molecules from the crystallographic structure of Drosophila melanogaster acetylcholinesterase (AChE, entry 1QO9 in the Protein Data Bank). Nine proposed reaction points for the hydrolysis mechanism were obtained, including four for the acylation step and five for the deacylation step. Our results indicate that in the Michaelis complex of the acylation step, a looser interaction between the substrate and the oxyanion hole may result from an amino acid change in the acyl pocket observed in insect as compared to the vertebrate enzyme. Detailed descriptions of the reaction profile for the formation of both acylation and deacylation tetrahedral intermediates were obtained. The results indicate the occurrence of partially concerted mechanisms, with deprotonation of the nucleophiles (Ser238 in the acylation step and a water molecule in the deacylation step) by His480 facilitating the nucleophilic additions. Both processes were completed by enthalpically favorable steps, formation of choline in the acylation step and of acetic acid in the deacylation step.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Bioorganic Chemistry - Volume 34, Issue 2, April 2006, Pages 77-89
Journal: Bioorganic Chemistry - Volume 34, Issue 2, April 2006, Pages 77-89
نویسندگان
Carlos Mauricio R. Sant'Anna, Andrea dos Santos Viana, Nailton Monteiro do Nascimento Junior,