TCR Triggering by pMHC Ligands Tethered on Surfaces via Poly(Ethylene Glycol) Depends on Polymer Length
Figure 2
Characterization and separation of PEG polymer linkers and IEkMCC-PEG conjugates.
(A) Compiled elution curves of nine PEG polymer linkers from a Superdex 200 10/300 GL gel filtration column. The polymers were detected through the weak UV absorption of the biotin group using a 245 nm UV detector. (B) Separation of the IEkMCC and PEG polymer reaction products. The reaction products were loaded on a Superdex 200 10/300 GL gel filtration column to separate IEkMCC-PEG conjugates, unreacted IEkMCC, and unreacted PEG polymers. The reaction products of PEG 15000, PEG 30000 and PEG 60000 were first purified with an IEk-binding affinity column to eliminate unreacted PEG polymers. The dotted vertical line indicates the elution volume of IEkMCC protein. The late elution peaks of unreacted polymers can be seen for PEGs ranging from PEG 88 to PEG 5000. In reaction with PEG 7500, unreacted IEkMCC and unreacted polymer formed a single peak that was eluted at a position between unconjugated IEkMCC and pure PEG 7500.