Binding of aminoglycoside antibiotics with modified A-site 16S rRNA construct containing non-nucleotide linkers

A comparative binding study of modified bovine immunodeficiency virus TAR RNA against its TAT peptide

Besides generating novel binding peptides or small molecules to their RNA target, successful design of chemically modified RNA constructs capable of tighter binding with their binding peptides is also of significant importance. Herein, the synthesis and binding studies of a series of both wt and mutant bovine immunodeficiency virus (BIV) TAR RNA constructs against its Tat peptide are reported. Understanding the requirements that enable RNA construct binding properties, especially at the hairpin loop or internal bulge, would afford potential therapeutic approaches to control the BIV life cycle.

A comparative binding study of BIV Tat peptide against its TAR RNA duplex, RNA–DNA heteroduplex and DNA duplex

Association between RNA and DNA strands to form RNA-DNA heteroduplex is important in many biological processes such as transcription, DNA replication and reverse transcription. Herein, binding affinities of a 17-mer BIV Tat peptide is compared with TAR DNA duplex, TAR RNA-DNA heteroduplex and TAR RNA duplex. It was observed that binding affinities of Tat peptide is comparable against DNA-RNA heteroduplex and RNA duplex, whereas DNA duplex binding is decidedly poor.

Footprinting, circular dichroism and UV melting studies on neomycin B binding to the packaging region of human immunodeficiency virus type-1 RNA

We have studied the binding of neomycin to a 171mer RNA (psi-RNA) from the packaging region of the LAI strain of human immunodeficiency virus type-1, HIV-1 (LAI). The RNase I footprinting studies reveal that the primary binding site for the drug is in stem-loop 1, which contains the dimer initiation site of HIV-1. Loading this site with neomycin causes a structural change in the RNA, allowing nucleotides in the neighboring stem-loop 2 to participate in the drug site. Drug binding to secondary sites induces structural changes in other stem-loops of the RNA. Footprinting plots, showing cutting at a site as a function of drug concentration, were analyzed using a two-state model to obtain relative site-specific binding constants. Circular dichroism measurements show that neomycin binding to psi-RNA changes the intensity of the strong negative CD band at 208 nm, confirming that neomycin induces structural changes. Melting studies of the RNA showed melting transitions in the absence of drug at 28.2, 37.2, 47.4, 55.5 and 60.8 degrees C. Only the first two were affected by drug binding, the reason for this being explained by our analysis.