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Backbone dynamics of the monomeric lambda repressor denatured state ensemble under nondenaturing conditions.

Publication ,  Journal Article
Chugha, P; Oas, TG
Published in: Biochemistry
February 6, 2007

Oxidizing two native methionine residues predominantly populates the denatured state of monomeric lambda repressor (MetO-lambdaLS) under nondenaturing conditions. NMR was used to characterize the secondary structure and dynamics of MetO-lambdaLS in standard phosphate buffer. 13Calpha and 1Halpha chemical shift indices reveal a region of significant helicity between residues 9 and 29. This helical content is further supported by the observation of medium-range amide NOEs. The remaining residues do not exhibit significant helicity as determined by NMR. We determined 15N relaxation parameters for 64 of 85 residues at 600 and 800 MHz. There are two distinct regions of reduced flexibility, residues 8-32 in the N-terminal third and residues 50-83 in the C-terminal third. The middle third, residues 33-50, has greater flexibility. We have analyzed the amplitude of the backbone motions in terms of the physical properties of the amino acids and conclude that conformational restriction of the backbone MetO-lambdaLS is due to nascent helix formation in the region corresponding to native helix 1. The bulkiness of amino acid residues in the C-terminal third leads to the potential for hydrophobic interactions, which is suggested by chemical exchange detected by the difference in spectral density J(0) at the two static magnetic fields. The more flexible middle region is the result of a predominance of small side chains in this region.

Duke Scholars

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

February 6, 2007

Volume

46

Issue

5

Start / End Page

1141 / 1151

Location

United States

Related Subject Headings

  • Viral Regulatory and Accessory Proteins
  • Viral Proteins
  • Repressor Proteins
  • Protein Structure, Secondary
  • Protein Denaturation
  • Protein Conformation
  • Pliability
  • Nitrogen
  • Motion
  • Methionine
 

Citation

APA
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MLA
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Chugha, P., & Oas, T. G. (2007). Backbone dynamics of the monomeric lambda repressor denatured state ensemble under nondenaturing conditions. Biochemistry, 46(5), 1141–1151. https://doi.org/10.1021/bi061371g
Chugha, Preeti, and Terrence G. Oas. “Backbone dynamics of the monomeric lambda repressor denatured state ensemble under nondenaturing conditions.Biochemistry 46, no. 5 (February 6, 2007): 1141–51. https://doi.org/10.1021/bi061371g.
Chugha, Preeti, and Terrence G. Oas. “Backbone dynamics of the monomeric lambda repressor denatured state ensemble under nondenaturing conditions.Biochemistry, vol. 46, no. 5, Feb. 2007, pp. 1141–51. Pubmed, doi:10.1021/bi061371g.
Journal cover image

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

February 6, 2007

Volume

46

Issue

5

Start / End Page

1141 / 1151

Location

United States

Related Subject Headings

  • Viral Regulatory and Accessory Proteins
  • Viral Proteins
  • Repressor Proteins
  • Protein Structure, Secondary
  • Protein Denaturation
  • Protein Conformation
  • Pliability
  • Nitrogen
  • Motion
  • Methionine