Skip to main content
. Author manuscript; available in PMC: 2014 Jul 25.
Published in final edited form as: Chem Biol. 2013 Jul 25;20(7):870–878. doi: 10.1016/j.chembiol.2013.04.019

Figure 5.

Figure 5

The T2CT di-domain fragment of AspA generates asperlicin C and D from exogenous Ant-Ant-L-Trp-SNAC. (A) Panel A shows UV-vis analyses of HPLC traces (280 nm) from the indicated incubations. Reactions contained 50mM Tris-HCl buffer, pH 7.5, in 100 μL. Reactions represented by traces i to iv contained 100 μM Ant-Ant-L-Trp-SNAC. 50 μM T2CT, 20 μM Sfp and 2 mM CoASH were added to reaction I; but only 50 μM T2CT was added in reaction ii; 50 μM CT, 20 μM Sfp and 2 mM CoASH were added in reaction iii; No enzyme was added in reaction iv. Traces (v to vii) are standards. The suite of asperlicin C, D and 1([M+H]+ = 407) are found in traces i and ii but not iii and iv. (B) Reaction scheme featuring nonenzymatic acyl exchange from the –SNAC to the T2 domain pantetheinyl thiol arm to yield the tripeptidyl-S-T2 covalent enzyme as substrate for cyclizing release by the downstream CT domain.