1.Chemoenzymatic synthesis of glycoengineered IgG antibodies and glycosite-specific antibody-drug conjugates
Tang F, Wang LX, Huang W
Glycoengineered therapeutic antibodies and glycosite-specific antibody-drug conjugates (gsADCs) have generated great interest among researchers because of their therapeutic potential. Endoglycosidase-catalyzed in vitro glycoengineering technology is a powerful tool for IgG Fc (fragment cystallizable) N-glycosylation remodeling. In this protocol, native heterogeneously glycosylated IgG N-glycans are first deglycosylated with a wild-type endoglycosidase. Next, a homogeneous N-glycan substrate, presynthesized as described here, is attached to the remaining N-acetylglucosamine (GlcNAc) of IgG, using a mutant endoglycosidase (also called endoglycosynthase) that lacks hydrolytic activity but possesses transglycosylation activity for glycoengineering. Compared with in vivo glycoengineering technologies and the glycosyltransferase-enabled in vitro engineering method, the current approach is robust and features quantitative yield, homogeneous glycoforms of produced antibodies and ADCs, compatibility with diverse natural and non-natural glycan structures, convenient exploitation of native IgG as the starting material, and a well-defined conjugation site for antibody modifications. Potential applications of this method cover a broad scope of antibody-related research, including the development of novel glycoengineered therapeutic antibodies with enhanced efficacy, site-specific antibody-drug conjugation, and site-specific modification of antibodies for fluorescent labeling, PEGylation, protein cross-linking, immunoliposome formation, and so on, without loss of antigen-binding affinity. It takes 5-8 d to prepare the natural or modified N-glycan substrates, 3-4 d to engineer the IgG N-glycosylation, and 2-5 d to synthesize the small-molecule toxins and prepare the gsADCs.
2.Copper-free click chemistry on polymersomes: Pre vs. Post-self-assembly functionalisation
Silvie A. Meeuwissen, et al.
The optimal accessibility of functional groups on polymeric nanosized vesicles was investigated with copper-free clickable probes as a model system. Cu-free clickable polymersomes were developed either through co-assembly of end group modified amphiphilic block copolymers or by introduction of the reactive moieties on preformed vesicles. For the co-assembly approach, the highest degree of availability was obtained for the most hydrophilic functional group, whereas hydrophobic species were unable to react as efficiently since they were seemingly buried in the membrane. Post-self-assembly introduction led to good results for all three examined moieties whereby surface saturation was reached above a certain percentage of immobilised probes. Finally, we demonstrated that protrusion of functional entities from the membrane corona via a longer hydrophilic segment of the block-copolymer significantly enhances the accessibility.
