title: Relationship between the native-state hydrogen exchange and the folding pathways of barnase.
abstract: The previous native-state hydrogen exchange experiment with barnase failed to detect any partially unfolded intermediate state which was contrary to the experimental results from kinetic deuterium hydrogen exchange pulse labeling and protein engineering studies. This has been taken to suggest that the native-state hydrogen exchange method cannot be used alone as an analytical tool to study the folding pathways of proteins. Here, we revisited the pulse labeling experiment with barnase and detected no stable folding intermediate. This finding allows a reconciliation of the native-state HX data and the folding pathway of barnase. Along with alternative theoretical interpretations for a curved chevron plot of protein folding, these data suggest that further investigation of the nature of the intermediate of barnase is needed.
authors.affiliation: Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Chu
authors.forename: J
authors.initials: J
authors.lastname: Takei
authors.forename: J J
authors.initials: JJ
authors.lastname: Barchi
authors.forename: Y
authors.initials: Y
authors.lastname: Bai
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D003903:Deuterium; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017510:Protein Folding; D011522:Protons; D012260:Ribonucleases / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D009587:Nitrogen Isotopes; D011522:Protons; D006859:Hydrogen; D003903:Deuterium; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease