RRM
2009 Rustbelt RNA Meeting
RRM
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Poster abstracts
Abstract:
The ability of cisplatin to serve as a highly effective chemotherapy drug has lead to numerous DNA-binding studies in order to elucidate the drug's mechanism of action. In contrast, research on the interactions of cisplatin with RNA has been very limited. DNA has been considered to be the major target of cisplatin, while RNA has been essentially overlooked. Previous studies in our laboratory demonstrated that RNA is the kinetically preferred target over DNA when similar sizes and structures of nucleic acids are compared. In the present study, we are extending our understanding of cisplatin-binding to the 790 loop of E. coli 16S ribosomal RNA (rRNA). The 790 loop has been shown to be important for ribosomal function, due to its presence in the inter-subunit region and binding site of protein IF3. In addition, this helix from 16S rRNA has been well studied by NMR and mutagenesis experiments. Our current task is to study the binding of cisplatin and various analogues to this small RNA construct and to explore the kinetics of interaction as well as the types and number of adducts formed with this helix. Our studies with full-length 16S rRNA revealed that cisplatin binds preferably to consecutive guanosine residues in helix 24 between positions 799 and 800, while its amino-acid analogues show preference for loop regions containing guanosine and adenosine. We have determined the number of platinum-complexes bound to RNA by using HPLC and atomic absorption spectroscopy, and identified the types of adducts formed by using LC-MS. Compared to mono- and bis-aquated forms of cisplatin, our data suggests that amino-acid derivatives exhibit different binding patterns and activities, which may provide further information towards their usefulness as probes of RNA structure and function.
Keywords: cisplatin, ribosomal RNA, 790 loop
