2 research outputs found
Design and Optimization of a Phosphopeptide Anchor for Specific Immobilization of a Capture Protein on Zirconium Phosphonate Modified Supports
The
attachment of affinity proteins onto zirconium phosphonate
coated glass slides was investigated by fusing a short phosphorylated
peptide sequence at one extremity to enable selective bonding to the
active surface via the formation of zirconium phosphate coordinate
covalent bonds. In a model study, the binding of short peptides containing
zero to four phosphorylated serine units and a biotin end-group was
assessed by surface plasmon resonance-enhanced ellipsometry (SPREE)
as well as in a microarray format using fluorescence detection of
AlexaFluor 647-labeled streptavidin. Significant binding to the zirconated
surface was only observed in the case of the phosphopeptides, with
the best performance, as judged by streptavidin capture, observed
for peptides with three or four phosphorylation sites and when spotted
at pH 3. When fusing similar phosphopeptide tags to the affinity protein,
the presence of four phosphate groups in the tag allows efficient
immobilization of the proteins and efficient capture of their target
Polymeric Iminosugars Improve the Activity of Carbohydrate-Processing Enzymes
Multivalent
iminosugars have recently emerged as powerful tools
to inhibit the activities of specific glycosidases. In this work,
biocompatible dextrans were coated with iminosugars to form linear
and ramified polymers with unprecedently high valencies (from 20 to
900) to probe the evolution of the multivalent inhibition as a function
of ligand valency. This study led to the discovery that polyvalent
iminosugars can also significantly enhance, not only inhibit, the
enzymatic activity of specific glycoside-hydrolase, as observed on
two galactosidases, a fucosidase, and a bacterial mannoside phosphorylase
for which an impressive 70-fold activation was even reached. The concept
of glycosidase activation is largely unexplored, with a unique recent
example of small-molecules activators of a bacterial O-GlcNAc hydrolase.
The possibility of using these polymers as “artificial enzyme
effectors” may therefore open up new perspectives in therapeutics
and biocatalysis