Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune...
The fluoronitrenoid metal complexes FNCoF 2 and FNRhF 2 as well as the first ternary Rh VI and Ir VI complexes NIrF 3 and NRhF 3 are described. They were obtained by the reaction of excited Group-9 metal atoms with NF 3 and their IR spectra, isolated in solid rare gases (neon and argon), were recorded. Aided by the observed 14/15 Ni sotope shifts and quantum-chemical predictions,a ll four stretching fundamentals of the novel complexes were safely assigned. The F À N stretching frequencies of the fluoronitrenoid complexes FNCoF 2 (1056.8 cm À1)a nd FNRhF 2 (872.6 cm À1)a re very different and their NÀMb onds vary greatly.I nF NCoF 2 ,t he FN ligand is singly bonded to Co and bears considerable iminyl/nitrene radical character,w hile the N À Rh bond in FNRhF 2 is astrong double bond with comparatively strong sand p-bonds.The anticipated rearrangement of FNCoF 2 to the nitrido Co VI complex is predicted to be endothermic and was not observed.
Substituting the P1 position in bovine pancreatic trypsin inhibitor (BPTI) is known to heavily influence its inhibitory activity towards serine proteases. Side-chain fluorinated aliphatic amino acids have been shown to...
Fluorinated amino acids play an important role in the
field of
peptide and protein engineering. Although numerous syntheses have
been published in recent decades, strategies that allow routine access
to fluorinated amino acids on a gram-scale have been poorly described.
Furthermore, the described pathways that gain fluorinated amino acids
are based on different synthetic strategies, making a uniform approach
that uses similar starting materials highly beneficial. Chiral Ni(II)
complexes were introduced as powerful tools in the synthesis of noncanonical
amino acids. In this work, we present a strategy for the synthesis
of a diverse range of fluorinated amino acids based on the corresponding
Ni(II) complex from which the products can be obtained in enantiopure
form (99% ee) on a gram-scale. In addition, we describe an optimized
procedure for the synthesis of alkyl iodide building blocks that are
required for the alkylation reactions with the corresponding Ni(II)
complex. Finally, we characterized the synthesized fluorinated amino
acids with regard to their hydrophobicity and α-helix propensity.
Fluorinated amino acids play an important role in the field of peptide and protein engineering. Although several different syntheses have been published in recent decades, obtaining fluorinated amino acids on a gram-scale still poses a challenge. Furthermore, the described pathways to obtain fluorinated amino acids are based on different synthetic strategies, making a uniform approach from similar starting materials highly interesting. Chiral Ni(II) complexes were introduced as powerful tools in the synthesis of non-canonical amino acids. In this work, we present a strategy for the synthesis of a diverse range of fluorinated amino acids from the corresponding Ni(II) complex on a gram-scale from which the products can be obtained in enantiopure form (>94%ee). In addition, we describe syntheses for alkyl iodide building blocks which are required for the alkylation reactions with the corresponding Ni(II) complex. Finally, we characterized the synthesized fluorinated amino acids with regard to their hydrophobicity and α-helix propensity.
The fluoronitrenoid metal complexes FNCoF 2 and FNRhF 2 as well as the first ternary Rh VI and Ir VI complexes NIrF 3 and NRhF 3 are described. They were obtained by the reaction of excited Group-9 metal atoms with NF 3 and their IR spectra, isolated in solid rare gases (neon and argon), were recorded. Aided by the observed 14/15 Ni sotope shifts and quantum-chemical predictions,a ll four stretching fundamentals of the novel complexes were safely assigned. The F À N stretching frequencies of the fluoronitrenoid complexes FNCoF 2 (1056.8 cm À1)a nd FNRhF 2 (872.6 cm À1)a re very different and their NÀMb onds vary greatly.I nF NCoF 2 ,t he FN ligand is singly bonded to Co and bears considerable iminyl/nitrene radical character,w hile the N À Rh bond in FNRhF 2 is astrong double bond with comparatively strong sand p-bonds.The anticipated rearrangement of FNCoF 2 to the nitrido Co VI complex is predicted to be endothermic and was not observed.
A de novo designed class of peptide-based fluoropolymers composed of fluorinated aliphatic amino acids as main components is reported. Structural characterization provided insights into fluorine-induced alterations on βstrand to α-helix transition upon an increase in SDS content and revealed the unique formation of PPII structures for trifluorinated fluoropeptides. A combination of circular dichroism, fluorescence-based leaking assays and surface enhanced infrared absorption spectroscopy served to examine the insertion and folding processes into unilamellar vesicles. While partitioning into lipid bilayers, the degree of fluorination conducts a decrease in α-helical content. Furthermore, this study comprises a report on the proteolytic stability of peptides exclusively built up by fluorinated amino acids and proved all sequences to be enzymatically degradable despite the degree of fluorination. Herein presented fluoropeptides as well as the distinctive properties of these artificial and polyfluorinated foldamers with enzyme-degradable features will play a crucial role in the future development of fluorinated peptide-based biomaterials.
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