CD properties of the fast‐ and slow‐folding forms of unfolded ribonuclease a

Schmid, Franz X.

doi:10.1016/0014-5793(82)80848-x

Cited by 2 publications

(3 citation statements)

References 11 publications

(11 reference statements)

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“…protein, resulting in biphasic fluorescence-detected unfolding kinetics for Y92W, as observed for WT RNase A (16)(17)(18)(19).…”

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confidence: 99%

“…Another interesting characteristic of RNase A is its biphasic fluorescence-detected unfolding kinetics (16,17). At low pH, the fast phase corresponds to the unfolding of the three-dimensional structure and can also be detected by absorbance and CD; the slow phase is silent in absorbance (17,18) and CD (16) and insensitive to GuHCl concentrations (16,18), and corresponds to the isomerization of proline residues next to the fluorescence reporters (Tyr, or Trp in mutants) (11,16,17,19).…”

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confidence: 99%

“…At low pH, the fast phase corresponds to the unfolding of the three-dimensional structure and can also be detected by absorbance and CD; the slow phase is silent in absorbance (17,18) and CD (16) and insensitive to GuHCl concentrations (16,18), and corresponds to the isomerization of proline residues next to the fluorescence reporters (Tyr, or Trp in mutants) (11,16,17,19). Because the sole tryptophan in the mutant proteins studied here is next to Pro-93, it reports on the isomeric state of Pro-93 in the unfolded Abbreviations: CF, continuous-flow; SF, stopped-flow.…”

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confidence: 99%

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Ultrarapid mixing experiments shed new light on the characteristics of the initial conformational ensemble during the folding of ribonuclease A

Welker

Maki

Shastry

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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The earliest folding events in single-tryptophan mutants of RNase A were investigated by fluorescence measurements by using a combination of stopped-flow and continuous-flow mixing experiments covering the time range from 70 s to 10 s. An ultrarapid double-jump mixing protocol was used to study refolding from an unfolded ensemble containing only native proline isomers. The continuous-flow measurements revealed a series of kinetic events on the submillisecond time scale that account for the burst-phase signal observed in previous stopped-flow experiments. An initial increase in fluorescence within the 70-s dead time of the continuous-flow experiment is consistent with a relatively nonspecific collapse of the polypeptide chain whereas a subsequent decrease in fluorescence with a time constant of Ϸ80 s is indicative of a more specific structural event. These rapid conformational changes are not observed if RNase A is allowed to equilibrate under denaturing conditions, resulting in formation of nonnative proline isomers. Thus, contrary to previous expectations, the isomerization state of proline peptide bonds can have a major impact on the structural events during early stages of folding.burst phase ͉ continuous-flow ͉ proline isomers ͉ stopped-flow

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“…protein, resulting in biphasic fluorescence-detected unfolding kinetics for Y92W, as observed for WT RNase A (16)(17)(18)(19).…”

mentioning

confidence: 99%