The slow folding reaction of barstar: the core tryptophan region attains tight packing before substantial secondary and tertiary structure formation and final compaction of the polypeptide chain 1 1Edited by C. R. Matthews

Sridevi, K.; Juneja, Juhi; Bhuyan, Abani K.; Krishnamoorthy, G.; Udgaonkar, Jayant B.

doi:10.1006/jmbi.2000.4060

Cited by 46 publications

(82 citation statements)

References 67 publications

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“…As a result, more I L will get labeled than expected, and the apparent rate constant, k L , for the labeling of the cysteine thiol in I L might be high in value. Finally, I L has been reported to be a heterogeneous assembly of structures (32)(33)(34), and it is possible that some of these might have one or more of the cysteine thiols not buried but solvent-exposed. This would lead to significant labeling of the cysteine thiol in I L .…”

Section: Discussionmentioning

confidence: 99%

“…A rapid equilibrium between U and I E is established before the major structural transition to the late intermediate I L occurs. I L has also been shown to be a heterogeneous ensemble of intermediates (32)(33)(34). Different members of the I E ensemble are populated in different solvent conditions; hence, the structural properties of I E appear different in different folding conditions (30,31).…”

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confidence: 99%

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Exploring the Cooperativity of the Fast Folding Reaction of a Small Protein Using Pulsed Thiol Labeling and Mass Spectrometry

Jha¹,

Udgaonkar

2007

Journal of Biological Chemistry

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It has been difficult to obtain directly residue-specific information on side chain packing during a fast (ms) protein folding reaction. Such information is necessary to determine the extent to which structural changes in different parts of the protein molecule are coupled together in defining the cooperativity of the overall folding transition. In this study, structural changes occurring during the major fast folding reaction of the small protein barstar have been characterized at the level of individual residue side chains. A pulsed cysteine labeling methodology has been employed in conjunction with mass spectrometry. This provides, with ms temporal resolution, direct information on structure formation at 10 different locations in barstar during its folding. Cysteine residues located on the surface of native barstar, at four different positions, remain fully solvent-accessible throughout the folding process, indicating the absence of any ephemeral nonnative structure in which these four cysteine residues get transiently buried. For buried cysteine residues, the rates of the change in cysteine-thiol accessibility to rapid chemical labeling by the thiol reagent methyl methanethiosulfonate appear to be dependent upon the location of the cysteine residue in the protein and are different from the rate measured by the change in tryptophan fluorescence. But the rates vary over only a 3-fold range. Nevertheless, a comparison of the kinetics of the change in accessibility of the cysteine 3 thiol with those of the change in the fluorescence of tryptophan 53, as well as of their denaturant dependences, indicates that the major folding reaction comprises more than one step.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Exploring the Cooperativity of the Fast Folding Reaction of a Small Protein Using Pulsed Thiol Labeling and Mass Spectrometry

Jha¹,

Udgaonkar

2007

Journal of Biological Chemistry

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“…The motional dynamics of Trp53, which is located at the core of the protein, are very sensitive to the overall structural characteristics of the protein. In the native (N) state of the protein, the decay of fluorescence anisotropy of Trp53 follows a single correlation time (j) of~5.1 ns [20,27]. This corresponds to the overall tumbling of the protein which has a molecular weight of~10 kD.…”

Section: Motional Dynamics Of Trp53 In Stable Structural Forms Of Barmentioning

confidence: 98%

“…Studies of the motional dynamics of tryptophan, observed through time-resolved fluorescence anisotropy measurements, provide a revealing insight into the complexities of protein folding dynamics [27,37]. The ability to observe the dynamics in an ensemble of heterogeneous molecules gives fluorescence-based methods an edge over high-resolution techniques such as NMR and X-ray crystallography.…”

Section: Tryptophan Dynamics and "Double Kinetics" In Protein Foldingmentioning

confidence: 99%

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Protein Dynamics and Protein Folding Dynamics Revealed by Time-Resolved Fluorescence

Saxena

Udgaonkar

Krishnamoorthy

Springer Series on Fluorescence

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Refolding of Cold‐Denatured Barstar Induced by Radio‐Frequency Heating: A New Method to Study Protein Folding by Real‐Time NMR Spectroscopy

Pintér

Schwalbe

2020

Angewandte Chemie

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The C40A/C82A double mutant of barstar has been shown to undergo cold denaturation abovet he water freezing point. By rapidly applying radio-frequency power to lossy aqueous samples,refolding of barstar from its cold-denatured state can be followed by real-time NMR spectroscopy. Since temperature-induced unfolding and refolding is reversible for this double mutant, multiple cycling can be utilized to obtain 2D real-time NMR data. Barstar contains two proline residues that adopt am ix of cis and trans conformations in the lowtemperature-unfolded state,w hich can potentially induce multiple folding pathways. The high time resolution real-time 2D-NMR measurements reported here show evidence for multiple folding pathwaysrelated to proline isomerization, and stable intermediates are populated. By application of advanced heating cycles and state-correlated spectroscopy, an alternative folding pathway circumventing the rate-limiting cis-trans isomerization could be observed. The kinetic data revealed intermediates on both, the slow and the fast folding pathway.

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The slow folding reaction of barstar: the core tryptophan region attains tight packing before substantial secondary and tertiary structure formation and final compaction of the polypeptide chain 1 1Edited by C. R. Matthews

Cited by 46 publications

References 67 publications

Exploring the Cooperativity of the Fast Folding Reaction of a Small Protein Using Pulsed Thiol Labeling and Mass Spectrometry

Exploring the Cooperativity of the Fast Folding Reaction of a Small Protein Using Pulsed Thiol Labeling and Mass Spectrometry

Protein Dynamics and Protein Folding Dynamics Revealed by Time-Resolved Fluorescence

Refolding of Cold‐Denatured Barstar Induced by Radio‐Frequency Heating: A New Method to Study Protein Folding by Real‐Time NMR Spectroscopy

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