The naturally split Npu DnaE intein exhibits an extraordinarily high rate in the protein trans-splicing reaction

We have studied the naturally split a subunit of the DNA polymerase III (DnaE) intein from Nostoc punctiforme PCC73102 (Npu) using purified proteins and determined an apparent first-order rate constant of (1.1 +/- 0.2) x 10(-2) s (1) at 37 degrees C. This represents the highest rate reported for the protein trans-splicing reaction so far (t(1/2) of similar to 60 s). Furthermore, the reaction was very robust and high-yielding with respect to different extein sequences, temperatures from 6 to 37 degrees C, and the presence of up to 6 M urea. Given these outstanding properties, the Npu DnaE intein appears to be the intein of choice for many applications in protein and cellular chemistry. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.