کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1984455 | 1539975 | 2007 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Characterisation of a bis(5â²-nucleosyl)-tetraphosphatase (asymmetrical) from Drosophila melanogaster
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کلمات کلیدی
Ap4A hydrolaseeGFPEGTADAPIP4aAPFNUDIXDIPP4′,6-diamidino-2-phenylindole - 4 '، 6-دیامیدینو-2-فنیلینولadenosine 5′-tetraphosphate - آدنوزین 5'-تتراسفاتEST - استReverse transcriptase - ترانس کریپتاز معکوس یا وارونویسExpressed Sequence Tag - تکرار اظهار نظرFluoride - فلوراید Drosophila melanogaster - مگس سرکه، مگس میوهpolymerase chain reaction - واکنش زنجیره ای پلیمرازPCR - واکنش زنجیرهٔ پلیمرازenhanced green fluorescent protein - پروتئین فلورسنت سبز افزایش یافته استdiadenosine polyphosphate - پلی فسفات دیادنوزین
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Characterisation of a bis(5â²-nucleosyl)-tetraphosphatase (asymmetrical) from Drosophila melanogaster Characterisation of a bis(5â²-nucleosyl)-tetraphosphatase (asymmetrical) from Drosophila melanogaster](/preview/png/1984455.png)
چکیده انگلیسی
The intracellular functions of diadenosine polyphosphates are still poorly defined. To understand these better, we have expressed and characterized a heat stable, 16.6 kDa Nudix hydrolase (Apf) that specifically metabolizes these nucleotides from a Drosophila melanogaster cDNA. Apf always produces an NTP product, with substrate preference depending on pH and divalent ion (Zn2+ or Mg2+). For example, diadenosine tetraphosphate is hydrolysed to ATP and AMP with Km, kcat and kcat/Km values 9 μM, 43 sâ1 and 4.8 μMâ1 sâ1 (pH 6.5, 0.1 mM Zn2+) and 12 μM, 13 sâ1 and 1.1 μMâ1 sâ1 (pH 7.5, 20 mM Mg2+), respectively. However, diadenosine hexaphosphate is efficiently hydrolysed to ATP only at pH 7.5 with 20 mM Mg2+ (Km, kcat and kcat/Km values of 15 μM 4.0 sâ1, and 0.27 μMâ1 sâ1). Fluoride potently inhibits diadenosine tetraphosphate hydrolysis in the presence of Mg2+ (IC50 = 20 μM), whereas it is ineffective in the presence of Zn2+, supporting the view that inhibition involves a specific, MgF3â-containing transition state analogue complex. Patterns of Apf expression in Drosophila tissues show Apf mRNA levels to be highest in embryos and adult females. Subcellular localization with Apf-EGFP fusion constructs reveals Apf to be predominantly nuclear, having an apparent preferential association with euchromatin and facultative heterochromatin. This supports a nuclear function for diadenosine tetraphosphate. Our results show Apf to be a fairly typical member of the bis (5â²-nucleosyl)-tetraphosphatase subfamily of Nudix hydrolases with features that distinguish it from a previously reported bis (5â²-nucleosyl)-tetraphosphatase hydrolase activity from Drosophila embryos.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The International Journal of Biochemistry & Cell Biology - Volume 39, Issue 5, 2007, Pages 943-954
Journal: The International Journal of Biochemistry & Cell Biology - Volume 39, Issue 5, 2007, Pages 943-954
نویسندگان
Lucinda Winward, William G.F. Whitfield, Timothy J. Woodman, Alexander G. McLennan, Stephen T. Safrany,