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Many foldamers, oligomers that adopt well-defined secondary structures, are now known, including many exhibiting functional behavior. However, examples of foldamer subunits within larger architectures remain rare, despite the importance of higher-order structure in biomacromolecules. Here, we investigate the dynamic covalent assembly of short o-phenylenes, a simple class of aromatic foldamers, into twisted macrocycles. o-Phenylene tetramers have been combined with rod-shaped p-phenylene-, tolane-, and diphenylbutadiyene-based linkers using imine formation. Macrocyclization proceeds efficiently, inducing folding of the o-phenylenes. The resulting [3+3] macrocycles (three o-phenylenes and three linkers) are shape-persistent, triangular structures with twisted cores and internal diameters up to approximately 2 nm. The homochiral D3-symmetric and heterochiral C2-symmetric conformers can be distinguished by NMR spectroscopy. Analysis of the conformational distribution for the p-phenylene-linked macrocycle suggests that the o-phenylene units are largely decoupled, with the less-symmetrical configuration therefore entropically favored. Conformational dynamics were assessed by variable-temperature NMR spectroscopy. Confinement within the macrocyclic architecture slows the inversion of the o-phenylene moieties.
This article was published in the following journal.
Name: Journal of the American Chemical Society
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Protein translocase in BACTERIA or CHLOROPLASTS that exports or secretes folded proteins. In GRAM-NEGATIVE BACTERIA, twin-arginine translocase (TAT) is involved in the export of folded proteins to the PERIPLASM. In chloroplasts, TAT is involved in transporting folded proteins across the membranes of THYLAKOIDS.
One ring heterocyclic compounds defined by C6H7NO. Permitted are any degree of hydrogenation, any substituents and any ortho-fused or ortho-peri-fused ring systems.
Gram-negative bacterial secretion systems which carry out the secretion of folded proteins.T2SSs secrete folded proteins from the PERIPLASMIC SPACE that have been exported there by SEC TRANSLOCASE or TAT SECRETION SYSTEMS, or they secrete folded proteins directly from the CYTOPLASM. The T2SSs have four substructures, an ATPase, an inner membrane platform, a pseudopilin, and secretin, an outer membrane complex which is a channel for secretion. (This bacterial secretin is not the same as the mammalian hormone also named SECRETIN.)
A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.