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Coronenohelicenes with Dynamic Chirality.

ABSTRACT: The synthesis of a new type of chiral and dynamic nonplanar aromatics containing a combination of fused perylene-based coronenes and helicenes is reported. Either one or two helicene moieties were fused to the bay regions of an extended perylene core. The target compounds contain either identical or two different helicene building blocks. The combination with two helicene units leads to six different isomers, including two pairs of enantiomers and two meso forms. The experimental determination of the isomerization barriers the corresponding double [5]-helicenes revealed activation energies of Ea =24.81 and 25.38?kcal?mol-1 , which is slightly above the barrier of the parent [5]-helicene. Resolution of all possible regio- and stereoisomers allowed for the systematic investigation of the chiroptical properties. They revealed remarkable dissymmetry factors Igabs I of up to 1.2×10-2 , which mirror the synergy between the strong absorbing perylenes and the inherent chirality of helicenes.

SUBMITTER: Weiss C

PROVIDER: S-EPMC7702068 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Coronenohelicenes with Dynamic Chirality.

Weiss Corinna C Sharapa Dmitry I DI Hirsch Andreas A

Chemistry (Weinheim an der Bergstrasse, Germany) 20200924 62

The synthesis of a new type of chiral and dynamic nonplanar aromatics containing a combination of fused perylene-based coronenes and helicenes is reported. Either one or two helicene moieties were fused to the bay regions of an extended perylene core. The target compounds contain either identical or two different helicene building blocks. The combination with two helicene units leads to six different isomers, including two pairs of enantiomers and two meso forms. The experimental determination o ...[more]

PMID: 32449817

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Project description:Genetic defects in protein O-mannosyltransferase 1 (POMT1) and POMT2 underlie severe muscular dystrophies. POMT genes are evolutionarily conserved in metazoan organisms. In Drosophila, both male and female POMT mutants show a clockwise rotation of adult abdominal segments, suggesting a chirality of underlying pathogenic mechanisms. Here we described and analyzed a similar phenotype in POMT mutant embryos that shows left-handed body torsion. Our experiments demonstrated that coordinated muscle contraction waves are associated with asymmetric embryo rolling, unveiling a new chirality marker in Drosophila development. Using genetic and live-imaging approaches, we revealed that the torsion phenotype results from differential rolling and aberrant patterning of peristaltic waves of muscle contractions. Our results demonstrated that peripheral sensory neurons are required for normal contractions that prevent the accumulation of torsion. We found that POMT mutants show abnormal axonal connections of sensory neurons. POMT transgenic expression limited to sensory neurons significantly rescued the torsion phenotype, axonal connectivity defects, and abnormal contractions in POMT mutant embryos. Together, our data suggested that protein O-mannosylation is required for normal sensory feedback to control coordinated muscle contractions and body posture. This mechanism may shed light on analogous functions of POMT genes in mammals and help to elucidate the etiology of neurological defects in muscular dystrophies.SIGNIFICANCE STATEMENT Protein O-mannosyltransferases (POMTs) are evolutionarily conserved in metazoans. Mutations in POMTs cause severe muscular dystrophies associated with pronounced neurological defects. However, neurological functions of POMTs remain poorly understood. We demonstrated that POMT mutations in Drosophila result in abnormal muscle contractions and cause embryo torsion. Our experiments uncovered a chirality of embryo movements and a unique POMT-dependent mechanism that maintains symmetry of a developing system affected by chiral forces. Furthermore, POMTs were found to be required for proper axon connectivity of sensory neurons, suggesting that O-mannosylation regulates the sensory feedback controlling muscle contractions. This novel POMT function in the peripheral nervous system may shed light on analogous functions in mammals and help to elucidate pathomechanisms of neurological abnormalities in muscular dystrophies.

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Coronenohelicenes with Dynamic Chirality.

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Coronenohelicenes with Dynamic Chirality.

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