Specific collapsed followed by slow hydrogen-bond formation of β-sheet in the folding of single-chain monellin

Tetsunari Kimura, Takanori Uzawa, Koichiro Ishimori, Isao Morishima, Satoshi Takahashi, Takashi Konno, Shuji Akiyama, Tetsuro Fujisawa

Research output: Contribution to journalArticlepeer-review

86 Citations (Scopus)

Abstract

Characterization of the conformational landscapes for proteins with different secondary structures is important in elucidating the mechanism of protein folding. The folding trajectory of single-chain monellin composed of a five-stranded β-sheet and a helix was investigated by using a pH-jump from the alkaline unfolded to native state. The kinetic changes in the secondary structures and in the overall size and shape were measured by circular dichroism spectroscopy and small-angle x-ray scattering, respectively. The formation of the tertiary structure was monitored by intrinsic and extrinsic fluorescence. A significant collapse was observed within 300 μs after the pH-jump, leading to the intermediate with a small amount of secondary and tertiary structures but with an overall oblate shape. Subsequently, the stepwise formation of secondary and tertiary structures was detected. The current observation was consistent with the theoretical prediction that a more significant collapse precedes the formation of secondary structures in the folding β-sheet proteins than that of helical proteins [Shea, J. E., Onuchic, J. N. & Brooks, C. L., III (2002) Proc. Natl. Acad. Sci. USA 99, 16064-16068]. Furthermore, it was implied that the initial collapse was promoted by the formation of some specific structural elements, such as tight turns, to form the oblate shape.

Original languageEnglish
Pages (from-to)2748-2753
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume102
Issue number8
DOIs
Publication statusPublished - 2005 Feb 22

Keywords

  • Energy landscape
  • Protein folding
  • Submillisecond dynamics
  • X-ray scattering

ASJC Scopus subject areas

  • General

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