Table 1. The final yields of the protein ligation by protein trans-splicing.

Intein	N-extein	C-extein	Yield (%) with 50 mM DTT	Yield (%) with 0.5 mM TCEP
NpuDnaE-IntN102/C36 (wild-type)	nSH3	cSH3	n.d.	n.d.
	GB1	cSH3	n.d.	n.d.
	nSH3	GB1	77±10	61±8
NpuDnaE-IntN123/C15	nSH3	cSH3	27±10	50±7
	Smt3	GB1	9±3	65±7

n.d., not detectable.