3 research outputs found
Two-Step Protein Labeling Utilizing Lipoic Acid Ligase and Sonogashira Cross-Coupling
Labeling
proteins in their natural settings with fluorescent proteins
or protein tags often leads to problems. Despite the high specificity,
these methods influence the natural functions due to the rather large
size of the proteins used. Here we present a two-step labeling procedure
for the attachment of various fluorescent probes to a small peptide
sequence (13 amino acids) using enzyme-mediated peptide labeling in
combination with palladium-catalyzed Sonogashira cross-coupling. We
identified <i>p</i>-iodophenyl derivatives from a small
library that can be covalently attached to a lysine residue within
a specific 13-amino-acid peptide sequence by Escherichia
coli lipoic acid ligase A (LplA). The derivatization
with <i>p</i>-iodophenyl subsequently served as a reactive
handle for bioorthogonal transition metal-catalyzed Sonogashira cross-coupling
with alkyne-functionalized fluorophores on both the peptide as well
as on the protein level. Our two-step labeling strategy combines high
selectivity of enzyme-mediated labeling with the chemoselectivity
of palladium-catalyzed Sonogashira cross-coupling
A Bioorthogonal Click Chemistry Toolbox for Targeted Synthesis of Branched and Well-Defined Protein-Protein Conjugates
A highly efficient technology for protein
functionalization with commonly used bioorthogonal motifs for Diels-Alder
cycloaddition with inverse electron demand (DAinv). With the aim of
precisely generating branched protein chimeras, we systematically assessed the
reactivity, stability and side product formation of various bioorthogonal
chemistries directly at the protein level. We demonstrate the efficiency and
versatility of our conjugation platform using different functional proteins and
the therapeutic antibody trastuzumab. This technology enables fast and routine
access to tailored and hitherto inaccessible protein chimeras useful for a
variety of scientific disciplines