Figure 2
From: Immune response to a potyvirus with exposed amino groups available for chemical conjugation
Availability of surface-exposed amino groups on TEV capsid protein for chemical conjugation to biotin-tagged reagent. A) Chemical structure of biotin-tagged reagent, Sulfo-NHS-SS-Biotin: the NHS ester group reacts specifically with the amino groups of amino acids; the spacer arm contains an S-S bond that can be cleaved by treatment with the reducing agent 2-mercaptoethanol; and biotin is attached on the other side of the spacer arm. B) 12% SDS-PAGE of untreated virus under nonreducing and reducing conditions (lanes 1 and 2, respectively) and biotinylated virus under nonreducing and reducing conditions (lanes 3 and 4, respectively) stained with Coomassie Blue. C) Western blot of treated and untreated samples. Lane 1: untreated virus under reducing conditions; lanes 2 and 3, biotinylated virus under nonreducing and reducing conditions, respectively. A streptavidin-horseradish peroxidase conjugate was used as the detection reagent. MWM, molecular weight marker. Bold arrows indicate main biotinylation products.