Interconnection of Salt-induced Hydrophobic Compaction and Secondary Structure Formation Depends on Solution Conditions

摘要: What happens in the early stage of protein folding remains an interesting unsolved problem. Rapid kinetics measurements with cytochrome c using submillisecond continuous flow mixing devices suggest simultaneous formation a compact collapsed state and secondary structure. These data seem to indicate that collapse is guided by specific short long range interactions (heteropolymer collapse). A contrasting interpretation also has been proposed, which suggests rapid, nonspecific, trivial solvent related compaction, could as well be observed homopolymer (homopolymer We address this controversy fluorescence correlation spectroscopy (FCS), enables us monitor salt-induced compaction accompanying associated time constant directly at single molecule resolution. In addition, we follow structure far UV CD. The presented here both these models heteropolymer) applicable depending on solution conditions. For example, not aqueous buffer. buffer, occurs through two-state co-operative transition following heteropolymer formalism, whereas takes place gradually. contrast, presence urea, radius gradually over extended salt concentration formalism. take simultaneously urea.