P2 (254, 368) showed a Band I hypsochromic shift of 4 nm suggesting conjugation at the 4'-hydroxyl group, which was confirmed by comparison with an authentic reference standard.
For quercetin (256, 372) only the product P1 (256, 372) did not show a hypsochromic shift suggesting conjugation at the 7-hydroxyl group.
Our results suggested that conjugation with CPP followed by encapsulation in MNPs provides an effective strategy for oral delivery of macromolecular therapeutics.
All protein dye bioconjugates were found to contain the rhodamine B dye by PAGE analysis (see SI, Figure S3), although LC-MS suggested incomplete conjugation (see SI, Figure S4).
The inability to further improve cross-linking when more than five molar excess of Protein Z was used suggested that conjugation in this case is limited by the formation of the covalent bond rather than Protein Z binding onto IgG.
No change in the mean diameter or size distribution was observed prior to modification (120 ± 54 nm) or after conjugation (128 ± 60 nm), suggesting the conjugation chemistry did not perturb exosome structure.
In fact, the simulation of traI is not sensitive to the conjugation penalty factor P λ upon infection, suggesting that conjugation may occur at the time of mixing (inoculation), before M13 phage attach the pili.
Although the analysis of the tra region suggests that conjugation is functional, initial attempts to transfer pVT1 through conjugation to E. coli after introduction of a suicide plasmid vector carrying a chloramphenicol cassette [41] in the gene encoding an IS4-like transposase (pVT1_36) were unsuccessful, even when we used a restriction minus strain such as DHα-T1 (see Material and Methods).
As shown in Figure 4c, we detected the accumulation of PTEN-SUMO2-purified conjugates in those cells treated with MG132, suggesting that conjugation of SUMO2 to PTEN might positively modulate its covalent interaction with ubiquitin.
These results suggest the conjugation of VS with GNP via bond between gold and sulfur, gold and nitrogen in the stable drug-gold conjugate.
