Quench-flow experiments combined with mass spectrometry show apomyoglobin folds through and obligatory intermediate.
Folding of apomyoglobin is characterized by formation of a compact intermediate that contains substantial helicity. To determine whether this intermediate is obligatory or whether the protein can fold directly into the native state via an alternate parallel pathway, we have combined quench-flow hydrogen-exchange pulse labeling techniques with electrospray ionization mass spectrometry. The mass spectra of apomyoglobin obtained at various refolding times suggest that apomyoglobin indeed folds through a single pathway containing an obligatory intermediate with a significant hydrogen-bonded secondary structure content.
Tsui
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V
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
Garcia
C
C
Cavagnero
S
S
Siuzdak
G
G
Dyson
H J
HJ
Wright
P E
PE
D000818:Animals; D001059:Apoproteins / Q000737:chemistry*; D006860:Hydrogen Bonding; D013058:Mass Spectrometry; D009211:Myoglobin / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D014907:Whales
D001059:Apoproteins; D009211:Myoglobin; D011994:Recombinant Proteins; C010857:apomyoglobin