RESUMO
Intramolecular S-acylation of a thiol-installed threonine with a thioester unit, followed by S-O acyl transfer and subsequent desulphurisation, allows the synthesis of lactone peptides. A protocol has been developed enabling the cyclisation of a linear peptide, a reaction which has not been achieved by conventional methods.
Assuntos
Lactonas/química , Peptídeos/síntese química , Compostos de Sulfidrila/química , Treonina/química , Estrutura Molecular , Peptídeos/químicaRESUMO
Proteins incorporating artificial moieties such as fluorophores and drugs have enjoyed increasing use in chemical biology and drug development research. Preparation of such artificial protein derivatives has relied mainly on native chemical ligation in which peptide/protein thioesters chemoselectively react with N-terminal cysteine (Cys) peptides to afford protein molecules. The protein thioesters derived from expressed proteins represent thioesters that are very useful for the preparation of artificial proteins by native chemical ligation with synthetic peptides with N-terminal Cys. We recently have developed a traceless thioester-producing protocol using carboxypeptidase Y (CPaseY) which is compatible with an expressed protein. The traceless character is ensured by CPaseY-mediated hydrazinolysis of C-terminal Xaa (X)-Cys-proline (Pro)-leucine (Leu)-OH sequence followed by an auto-processing of the Cys-Pro (CP) dipeptide unit, affording the corresponding X-thioester (X-SR). However, hydrazinolysis of the amide bond in the prolyl leucine junction depends significantly on the nature of X. In the case of hydrophobic X residues, the hydrazinolysis overreacts to give several hydrazides while the reaction of hydrophilic X residues proceeds slowly. In this research, we attempted to develop an X-independent CPaseY-mediated protocol and found that the incorporation of a triple CP sequence into the C-terminal end (X-(CP)3-Leu-OH) allows for efficient X-SR formation in a manner that is independent of X.
Assuntos
Catepsina A/metabolismo , Hidrazinas/química , Peptídeos/química , Proteínas/química , Amidas/química , Sequência de Aminoácidos , Cisteína/química , Leucina/química , Prolina/química , Relação Estrutura-Atividade , Compostos de Sulfidrila/químicaRESUMO
A traceless thioester-producing protocol featuring carboxypeptidase Y-mediated hydrazinolysis of cysteinyl prolyl leucine-tagged peptides has been developed. The hydrazinolysis followed by thioesterification affords cysteinyl prolyl thioesters. Self-editing of the tag and subsequent trans-thioesterification yields peptide thioesters. The developed protocol was successfully applied to the conversion of recombinant proteins to thioesters.
Assuntos
Carboxipeptidases/metabolismo , Cisteína/metabolismo , Ésteres/metabolismo , Hidrazinas/metabolismo , Compostos de Sulfidrila/metabolismo , Cisteína/química , Ésteres/química , Hidrazinas/química , Conformação Molecular , Compostos de Sulfidrila/químicaRESUMO
A photoresponsive amide cleavage device was developed based on the asparagine imidation-mediated cleavage of peptide bonds during intein-mediated protein splicing. The chemical environment of the protein splicing process was mimicked by the incorporation of geminal dimethyl groups and a secondary amine unit in asparagine scaffold. Furthermore, the resulting photoresponsive device could induce the phototriggered cleavage of an amide bond by the protection of the secondary amine unit with an o-nitrobenzyloxycarbonyl group.
Assuntos
Amidas/química , Asparagina/química , Inteínas/genética , Amidas/metabolismo , Modelos Moleculares , Processos Fotoquímicos , Processamento de ProteínaRESUMO
Spatiotemporal control of peptide nanofibre growth was achieved by photocleavage of a DNA-conjugated ß-sheet forming peptide that is linked through a photoresponsive amino acid residue. Peptide nanofibres were selectively formed by photocleaving the conjugate on a complementary DNA-immobilised glass substrate.
Assuntos
DNA Complementar/química , Hibridização de Ácido Nucleico , Peptídeos/química , Aminoácidos/química , Vidro/química , Peptídeos/síntese química , Processos Fotoquímicos , Raios UltravioletaRESUMO
Bridged peptides including stapled peptides are attractive tools for regulating protein-protein interactions (PPIs). An effective synthetic methodology in a heterogeneous system for the preparation of these peptides using olefin metathesis and hydrogenation of protected peptides with a long aliphatic chain anchor is reported.
Assuntos
Alcenos/química , Peptídeos/síntese química , Hidrogenação , Estrutura Molecular , Peptídeos/químicaRESUMO
A traceable linker that is potentially applicable to identification of a target protein of bioactive compounds was developed. It enabled not only thiol-induced cleavage of the linker for enrichment of the target protein but also selective labelling to pick out the target from contaminated non-target proteins for facile identification.