5 research outputs found
Synthesis of scpBNA‑<sup>m</sup>C, -A, and -G Monomers and Evaluation of the Binding Affinities of scpBNA-Modified Oligonucleotides toward Complementary ssRNA and ssDNA
We previously reported
the synthesis and evaluation of 2′-<i>O</i>,4′-<i>C</i>-spirocyclopropylene-bridged
nucleic acid (scpBNA) bearing a thymine (T) nucleobase. Oligonucleotides
(ONs) modified with scpBNA-T exhibited strong binding affinity to
complementary single-stranded RNA (ssRNA) and high enzymatic stability.
These biophysical properties suggest that scpBNAs are well suited
for use in antisense strategies. Herein, we describe the synthesis
of scpBNA monomers bearing 5-methylcytosine (<sup>m</sup>C), adenine
(A), and guanine (G) nucleobases for use in a variety of sequences.
The prepared scpBNA monomers were incorporated into ONs at various
positions. The scpBNA-modified ONs exhibited excellent duplex-forming
ability with the complementary ssRNA comparable to ONs modified with
2′-<i>O</i>,4′-<i>C</i>-methylene-bridged
nucleic acid (2′,4′-BNA/LNA). Moreover, ON modified
with scpBNA-<sup>m</sup>C, -A, and -G showed higher enzymatic stability
than the corresponding 2′,4′-BNA/LNA-modified ON. These
results demonstrated a promising role for the incorporation of scpBNA
monomers into therapeutic antisense ONs
Synthesis and Properties of Nucleobase-Sugar Dual Modified Nucleic Acids: 2<b>′</b>‑OMe-RNA and scpBNA Bearing a 5‑Hydroxycytosine Nucleobase
Naturally occurring 5-hydroxycytosine (5‑OHCyt),
which is associated with DNA damage, was recently found to reduce
the hepatotoxicity of antisense oligonucleotides (ASOs) without compromising
its antisense activity when used as a replacement for cytosine (Cyt).
Additionally, sugar-modified nucleic acids, such as 2′-O-methylribonucleic acid (2′-OMe-RNA) and 2′-O,4′-C-spirocyclopropylene-bridged
nucleic acid (scpBNA), have emerged as useful antisense materials.
Herein, we aimed to combine these two advantages by designing dual
modified nucleic acids 2′-OMe-RNA-5‑OHCyt
and scpBNA-5‑OHCyt bearing the 5‑OHCyt nucleobase to develop efficient and safe ASOs. We describe the
synthesis of 2′-OMe-RNA-5‑OHCyt and scpBNA-5‑OHCyt phosphoramidites and their incorporation into
oligonucleotides (ONs). The duplex-forming ability and base discrimination
properties of 2′-OMe-RNA-5‑OHCyt- and scpBNA-5‑OHCyt-modified ONs were similar to those of 2′-OMe-RNA-Cyt-
and scpBNA-mCyt-modified ONs, respectively. We also synthesized
two 2′-OMe-RNA-5‑OHCyt-modified ASOs, and
one of the two was found to exhibit reduced hepatotoxicity while retaining
target mRNA knockdown activity in in vivo experiments
Design and Concise Synthesis of a Novel Type of Green Fluorescent Protein Chromophore Analogue
A small molecular model compound for the green fluorescent protein chromophore was readily synthesized by a novel condensation reaction of (thio)imidate with imino-ester via an aziridine intermediate. This compound showed fluorescence in the solid and frozen solution states but not in the solution state. Its fluorescent property was successfully applied in the detection of dsDNA
Design and Concise Synthesis of a Novel Type of Green Fluorescent Protein Chromophore Analogue
A small molecular model compound for the green fluorescent protein chromophore was readily synthesized by a novel condensation reaction of (thio)imidate with imino-ester via an aziridine intermediate. This compound showed fluorescence in the solid and frozen solution states but not in the solution state. Its fluorescent property was successfully applied in the detection of dsDNA
Inhibitors for Bacterial Cell-Wall Recycling
Gram-negative bacteria have evolved an elaborate process
for the
recycling of their cell wall, which is initiated in the periplasmic
space by the action of lytic transglycosylases. The product of this
reaction, β-d-<i>N-</i>acetylglucosamine-(1→4)-1,6-anhydro-β-d-<i>N-</i>acetylmuramyl-l-Ala-γ-d-Glu-<i>meso</i>-DAP-d-Ala-d-Ala
(compound <b>1</b>), is internalized to begin the recycling
events within the cytoplasm. The first step in the cytoplasmic recycling
is catalyzed by the NagZ glycosylase, which cleaves in a hydrolytic
reaction the <i>N</i>-acetylglucosamine glycosidic bond
of metabolite <b>1</b>. The reactions catalyzed by both the
lytic glycosylases and NagZ are believed to involve oxocarbenium transition
species. We describe herein the synthesis and evaluation of four iminosaccharides
as possible mimetics of the oxocarbenium species, and we disclose
one as a potent (compound <b>3</b>, <i>K</i><sub>i</sub> = 300 ± 15 nM) competitive inhibitor of NagZ