Non-native structure appears in microseconds during the folding of E. coli RNase H.

ABSTRACT: The folding pathway of Escherichia coli RNase H is one of the best experimentally characterized for any protein. In spite of this, spectroscopic studies have never captured the earliest events. Using continuous-flow microfluidic mixing, we have now observed the first several milliseconds of folding by monitoring the tryptophan fluorescence lifetime (60 μs dead time). Two folding intermediates are observed, the second of which is the previously characterized I(core) millisecond intermediate. The new earlier intermediate is likely on-pathway and appears to have long-range non-native structure, providing a rare example of such non-native structure formation in a folding pathway. The tryptophan fluorescence lifetimes also suggest a deviation from native packing in the second intermediate, I(co

SUBMITTER: Rosen LE 

PROVIDER: S-EPMC4624390 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature