PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 16240319

Liquid-crystalline supramolecular polymers formed through complementary nucleobase-pair interactions.

Sona Sivakova·Jian Wu·Cheryl J Campo·Patrick T Mather·Stuart J Rowan
View original source ↗Export metadata ↓

Abstract

We report how the placement of nucleobase units, thymine, or N6-(4-methoxybenzoyl)adenine, onto the ends of a mesogenic core, bis-4-alkoxy-substituted bis(phenylethynyl)benzene, affects the properties of these materials. We show that addition of these bulky polar groups significantly reduces the range of liquid-crystalline behavior of these compounds. However, mixing two complementary nucleobase-containing AA- and BB-type monomer units together does result in the formation of stable, thermotropic liquid-crystalline (LC) phases. Hydrogen bonding is shown to play an important role in the formation of these LC phases, consistent with the formation of oligomeric or polymeric hydrogen-bonded aggregates. X-ray analyses of these mixed materials are consistent with the formation of smectic C phases.

Explore related subjects

AdenineBase PairingBenzeneDNA, ComplementaryHydrogen BondingLiquid CrystalsPolymersThymineJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sona Sivakova, Jian Wu, Cheryl J Campo, Patrick T Mather, Stuart J Rowan. 2005-12-23. Liquid-crystalline supramolecular polymers formed through complementary nucleobase-pair interactions.. https://doi.org/10.1002/chem.200500827

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

A distinct subclade of AlkB family demethylases in ciliates safeguards the positional fidelity of eukaryotic N6-methyladenine (6mA).

DNA N6-methyladenine (6mA) is a newly recognized transcription-associated epigenetic mark in eukaryotes. While its methylation pathway has been well established, the identity of eukaryotic 6mA demethylase(s) responsible for its removal and dynamic regulation has remained elusive. Here, we identify and characterize DMT3 (TtALKBH5), an AlkB family dioxygenase in Tetrahymena thermophila, as a 6mA demethylase in ciliates and potentially several other unicellular eukaryotes with abundant 6mA and a defined AMT1 methyltransferase (MTase) complex, supported by genetic and molecular evidence. DMT3 acts on both fully and hemimethylated ApT dinucleotides, an activity partially facilitated by a naturally occurring cysteine-to-serine substitution. Genome profiling shows that DMT3 is enriched at transcription start sites (TSSs) of 6mA-enriched genes, complementary to the occupancy pattern of the AMT1 complex, where it selectively removes spurious 6mA deposited by AMT1. Genetic disruption of DMT3-mediated demethylation, either by knockout or catalytic inactivation, leads to aberrant 6mA accumulation at TSS regions, transcriptional dysregulation, altered chromatin accessibility, and impaired initiation of sexual reproduction. Notably, simultaneous removal of DMT3 and AMT1 eliminates these defects, indicating that spurious TSS 6mA underlies transcriptional and developmental impairment.

Adenine↗
PubMed2007

A novel type of autophagy occurs together with vacuole genesis in miniprotoplasts prepared from tobacco culture cells.

Mature plant cells have large vacuoles. But how these vacuoles are formed has not been fully understood. It has been reported that autophagy is involved in the genesis of plant vacuoles. Thus we examined whether autophagy occurs in the vacuole genesis of a plant cell model called miniprotoplasts, in which preexisting large vacuoles have been removed. We prepared miniprotoplasts from tobacco culture cells (BY-2) and observed the formation of vacuoles by light and electron microscopy. The miniprotoplasts had few vacuoles immediately after preparation, but had large vacuoles after 1 to 2 d. When the cysteine protease inhibitor E-64c or E-64d was added to culture media, almost all vacuoles formed contained materials of cytoplasmic origin. This result suggests that autophagy occurs together with the genesis of the vacuoles in miniprotoplasts. 3-Methyladenine and phosphatidylinositol 3-kinase inhibitors such as wortmannin and LY294002, all of which block starvation?induced autophagy in tobacco culture cells and constitutive autophagy in Arabidopsis root cells, did not affect the autophagy in miniprotoplasts. Thus the form of autophagy in miniprotoplasts is probably different from the form of autophagy that arises as a result of sucrose starvation and constitutive autophagy in root tip cells. The causal connection between autophagy and vacuole genesis in miniprotoplasts was not clarified in this study.

Adenine↗