کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10803626 | 1057162 | 2014 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mutational analysis of residues in human arsenic (III) methyltransferase (hAS3MT) belonging to 5Â Ã
around S-adenosylmethionine (SAM)
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کلمات کلیدی
HPLC-ICP-MSHigh performance liquid chromatography-inductively coupled plasma-mass spectrometryS-adenosylmethionine (SAM)AS3MTMMAiAsSAMIPTGATR-FTIRDMAInorganic arsenic - آرسنیک معدنیS-adenosylmethionine - اس-ادنوزیل متیونینsodium dodecyl sulfate-polyacrylamide gel electrophoresis - الکتروفورز ژل دوده سولفات سدیم پلی آکریل آمیدSDS-PAGE - الکتروفورز ژل پلی آکریل آمیدisopropyl β-D-thiogalactopyranoside - ایزوپروپیل β-D-thiogalactopyranosideMutants - جهشwild-type - نوع وحشی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The functions of residues 57-RY-58, G60, L77, 80-GSGR-83, I101, T104, 134-GY-135, N155, V157 and 160-LV-161 in human arsenic (III) methyltransferase (hAS3MT) 5Â Ã
around S-adenosylmethionine (SAM) have not been studied. Herein, sixteen mutants were designed by substituting these residues with Ala. Mutants G60A, G80A, I101A, N155A and L160A were completely inactive. Only MMA was detected when mutants R57A, Y58A, G82A and T104A were used as the enzymes, which suggested that their catalytic activities were seriously impaired compared with that of wild type (WT). The catalytic capacities of other mutants were also lower than that of WT-hAS3MT. The KM(SAM) values of mutants were 1.9-8.7 times that of WT, suggesting their affinities to SAM were weakened. As evidenced by the experimental data herein, earlier literature and the model of hAS3MT-SAM, 57-RYYG-60, G78, G80, G82 and 155-NCV-157 interacted with the methionine of SAM, and 101-IDMT-104 and 135-YIE-137 were associated with the nucleotide adenosine of SAM. Since C156 and L160 were the common residues between 5Â Ã
around SAM and 5Â Ã
around As, and C156S and L160A were inactive, we proposed that C156 and L160 functioned in the methyl transfer process. G78, G80 and G82 belonging to the consensus GxGxG were located in a loop connecting the first β-strand and α-helix in the Rossmann fold core. Y59, N155, C156 and L160 oriented S+-CH3 during its approach to the arsenic lone pair, and further activated methyl transfer. G78, D102, M103, T104, I136 and N155 formed hydrogen bonds with SAM.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimie - Volume 107, Part B, December 2014, Pages 396-405
Journal: Biochimie - Volume 107, Part B, December 2014, Pages 396-405
نویسندگان
Xiangli Li, Zhirong Geng, Jiayin Chang, Xiaoli Song, Zhilin Wang,