The place of inactivated actin and its kinetic predecessor in actin folding-unfolding.
The kinetics of actin unfolding induced by guanidine hydrochloride of different concentrations was studied. The parametric representation of the kinetic dependencies of tryptophan fluorescence intensity changes recorded at two wavelengths allowed us to detect and characterize a new essentially unfolded kinetic intermediate. Its characteristics suggested that this intermediate state is a premolten globule. It was shown that the equilibrium transition between inactivated and completely unfolded states is also a two-step process and proceeds via an essentially unfolded kinetic intermediate. The new kinetic pathway of actin unfolding--refolding was proposed. According to it, the founded essentially unfolded kinetic state is the on-pathway intermediate, while inactivated actin is the off-pathway misfolded state stabilized by aggregation of partially folded macromolecules of protein.
Kuznetsova
Irina M
IM
Institute of Cytology, Russian Academy of Science, St. Petersburg 194064, Russia.
Stepanenko
Olga V
OV
Stepanenko
Olesia V
OV
Povarova
Olga I
OI
Biktashev
Alexander G
AG
Verkhusha
Vladislav V
VV
Shavlovsky
Mikhail M
MM
Turoverov
Konstantin K
KK
D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry; D007700:Kinetics; D018482:Muscle, Skeletal / Q000737:chemistry; D011489:Protein Denaturation; D017510:Protein Folding; D011817:Rabbits; D013050:Spectrometry, Fluorescence
D000199:Actins; D004492:Edetic Acid; D019791:Guanidine