Relationship between the native-state hydrogen exchange and the folding pathways of barnase

The pulse labeling experiment with barnase has been re-done and no stable folding intermediate found. A native-state hydrogen exchange experiment has been carried out with barnase with no detection of any partially unfolded intermediate state, not consistent with results from kinetic deuterium hydrogen exchange pulse labeling and protein engineering studies. Data indicate that more investigation of the nature of the intermediate of barnase is needed.