Ligand-free form of human alpha-fetoprotein: evidence for the molten globule state.
By means of circular dichroism and fluorescence spectroscopy, viscometry and scanning microcalorimetry we have shown that the release of ligands from human alpha-fetoprotein (AFP) results in a considerable rearrangement of the protein molecule. Ligand-free form is practically as compact as the native molecule and has native-like content of secondary structure but no rigid tertiary structure. This means that the release of ligands transforms the AFP molecule into a molten globule state. Stripping the ligands from AFP is the irreversible process, i.e., native protein molecule cannot be reconstituted from the ligand-free form of AFP by adding back ligands. A possible functional role of such a structural transformation is discussed.
Uversky
V N
VN
Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation. uversky@sun.ipr.serpukhov.su
Narizhneva
N V
NV
Ivanova
T V
TV
Kirkitadze
M D
MD
Tomashevski AYu
D006801:Humans; D008024:Ligands; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D000509:alpha-Fetoproteins / Q000737:chemistry*
D008024:Ligands; D000509:alpha-Fetoproteins