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The role of a beta-bulge in the folding of the beta-hairpin structure in ubiquitin.

ABSTRACT: It is known that the peptide corresponding to the N-terminal beta-hairpin of ubiquitin, U(1-17), can populate the monomeric beta-hairpin conformation in aqueous solution. In this study, we show that the Gly-10 that forms the bulge of the beta-turn in this hairpin is very important to the stability of the hairpin. The deletion of this residue to desG10(1-16) unfolds the structure of the peptide in water. Even under denaturing conditions, this bulge appears to be important in maintaining the residual structure of ubiquitin, which involves tertiary interactions within the sequence 1 to 34 in the denatured state. We surmise that this residual structure functions as one of the nucleation centers in the folding process and is important in stabilizing the transition state. In accordance with this idea, deleting Gly-10 slows down the refolding and unfolding rate by about one half.

SUBMITTER: Chen PY

PROVIDER: S-EPMC2374220 | biostudies-literature | 2001 Oct

REPOSITORIES: biostudies-literature

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The role of a beta-bulge in the folding of the beta-hairpin structure in ubiquitin.

Chen P Y PY Gopalacushina B G BG Yang C C CC Chan S I SI Evans P A PA

Protein science : a publication of the Protein Society 20011001 10

It is known that the peptide corresponding to the N-terminal beta-hairpin of ubiquitin, U(1-17), can populate the monomeric beta-hairpin conformation in aqueous solution. In this study, we show that the Gly-10 that forms the bulge of the beta-turn in this hairpin is very important to the stability of the hairpin. The deletion of this residue to desG10(1-16) unfolds the structure of the peptide in water. Even under denaturing conditions, this bulge appears to be important in maintaining the resid ...[more]

PMID: 11567097

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