Detecting Proteins Glycosylation by a Homogeneous Reaction System with Zwitterionic Gold Nanoclusters

Homogeneous
gold nanoclusters (Au NCs) have been widely utilized
in drug delivery, chemical sensing, bioassays, and biolabeling due
to their unique physical and chemical properties. However, little
attention has been paid to their application in detecting protein
post-translational modifications. Herein, we describe the development
of a homogeneous reaction system with water-soluble zwitterionic Au
NCs to capture glycopeptides from complex biological samples. The
unique characteristics of Au NCs, such as their molecular-like properties,
the excellent homogeneity in aqueous solution, the organic solvent
responsive precipitation, and the easy preparation in only 4.5 h,
contribute to the high efficiency and high throughput for capturing
the targeted glycopeptides. Compared with the conventional heterogeneous
system with solid-state adsorbents, the number of characterized glycosylation
sites was improved by 35%. Finally, an MS detection limit as low as
50 amol was achieved for the standard glycoprotein (IgG), and 1576
glycosylation sites from 713 glycoproteins were identified from only
60 μg of mouse liver protein. Data are available via ProteomeXchange
with identifier PXD005635.