کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1175700 | 961814 | 2006 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: An activity-dependent assay for ricin and related RNA N-glycosidases based on electrochemiluminescence An activity-dependent assay for ricin and related RNA N-glycosidases based on electrochemiluminescence](/preview/png/1175700.png)
Synthetic biotinylated RNA substrates were cleaved by the combined actions of ricin holotoxin and a chemical agent, N,N′-dimethylethylenediamine. The annealing of the product with a ruthenylated oligodeoxynucleotide resulted in the capture of ruthenium chelate onto magnetic beads, enabling the electrochemiluminescence (ECL)-based detection of RNA N-glycosidase activities of toxins. ECL immunoassays and the activity assay exhibited similar limits of detection just below signals with 0.1 ng/ml of ricin; the ECL response was linear as the ricin concentration increased by two orders of magnitude. Activities were detected with other adenine-specific RNA N-glycosidases, including Ricinus communis agglutinin (RCA), saporin, and abrin II. The substrate that provided the greatest sensitivity was composed of a four-residue loop, GdAGA, in a hairpin structure. When the 2′-deoxyadenosine (dA) was substituted with adenosine (A), 2′-deoxyinosine, or 2′-deoxyuridine, toxin-dependent signals were abolished. Placing the GdAGA motif in a six-residue loop or replacing it with GdAdGA or GdAAA resulted in measurable activities and signal patterns that were reproducible for a given toxin. Data indicated that saporin and abrin II shared one pattern, while ricin and RCA shared a distinct pattern. A monoclonal antibody that enhanced the activities of ricin, RCA, and abrin II to different extents, thus improving the diagnostic potential of the assay, was identified .
Journal: Analytical Biochemistry - Volume 357, Issue 2, 15 October 2006, Pages 200–207