Increasing Protein Conformational Stability by Optimizing β-Turn Sequence

Saul R. Trevino, Stephanie Ramadan, J. Martin Scholtz, C. Nick Pace

Research output: Contribution to journalArticle

87 Citations (Scopus)


Protein conformational stability is an important concern in many fields. Here, we describe a strategy for significantly increasing conformational stability by optimizing β-turn sequence. Proline and glycine residues are statistically preferred at several β-turn positions, presumably because their unique side-chains contribute favorably to conformational stability in certain β-turn positions. However, β-turn sequences often deviate from preferred proline or preferred glycine. Therefore, our strategy involves replacing non-proline and non-glycine β-turn residues with preferred proline or preferred glycine residues. Here, we develop guidelines for selecting appropriate mutations, and present results for five mutations (S31P, S42G, S48P, T76P, and Q77G) that significantly increase the conformational stability of RNase Sa. The increases in stability ranged from 0.7 kcal/mol to 1.3 kcal/mol. The strategy was successful in overlapping or isolated β-turns, at buried (up to 50%) or completely exposed sites, and at relatively flexible or inflexible sites. Considering the significant number of β-turn residues in every globular protein and the frequent deviation of β-turn sequences from preferred proline and preferred glycine residues, this simple, efficient strategy will be useful for increasing the conformational stability of proteins.

Original languageEnglish
Pages (from-to)211-218
Number of pages8
JournalJournal of Molecular Biology
Issue number1
Publication statusPublished - 12 Oct 2007
Externally publishedYes



  • β-turn
  • glycine
  • proline
  • protein conformational stability

ASJC Scopus subject areas

  • Molecular Biology

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