Min-21 and Min-23, the Smallest Peptides That Fold Like a Cystine-Stabilized -Sheet Motif: Design, Solution Structure
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- 作者：Annie Heitz ; Dung Le-Nguyen ; and Laurent Chiche
- 刊名：Biochemistry
- 出版年：1999
- 出版时间：August 10, 1999
- 年：1999
- 卷：38
- 期：32
- 页码：10615 - 10625
- 全文大小：193K
- 年卷期：v.38,no.32(August 10, 1999)
- ISSN：1520-4995
文摘
Small disulfide-rich proteins provide examples of simple and stable scaffolds for designpurposes. The cystine-stabilized 
le">-sheet (CSB) motif is one such elementary structural motif and is foundin many protein families with no evolutionary relationships. In this paper, we present NMR structuralstudies and stability measurements of two short peptides of 21 and 23 residues that correspond to theisolated CSB motif taken from a 28-residue squash trypsin inhibitor. The two peptides contain two disulfidebridges instead of three for the parent protein, but were shown to fold in a native-like fashion, indicatingthat the CSB motif can be considered an autonomous folding unit. The 23-residue peptide was truncatedat the N-terminus. It has a well-defined conformation close to that of the parent squash inhibitor, andalthough less stable than the native protein, it still exhibits a high Tm of about 100 
C. We suggest thatthis peptide is a very good starting building block for engineering new bioactive molecules by graftingdifferent active or recognition sites onto it. The 21-residue peptide was further shortened by removingtwo residues in the loop connecting the second and third cysteines. This peptide exhibited a less well-defined conformation and is less stable by about 1 kcal mol-1, but it might be useful if a higher flexibilityis desired. The lower stability of the 21-residue peptide is supposed to result from inadequate lengths ofsegments connecting the first three cysteines, thus providing new insights into the structural determinantsof the CSB motif.
le">-sheet (CSB) motif is one such elementary structural motif and is foundin many protein families with no evolutionary relationships. In this paper, we present NMR structuralstudies and stability measurements of two short peptides of 21 and 23 residues that correspond to theisolated CSB motif taken from a 28-residue squash trypsin inhibitor. The two peptides contain two disulfidebridges instead of three for the parent protein, but were shown to fold in a native-like fashion, indicatingthat the CSB motif can be considered an autonomous folding unit. The 23-residue peptide was truncatedat the N-terminus. It has a well-defined conformation close to that of the parent squash inhibitor, andalthough less stable than the native protein, it still exhibits a high Tm of about 100 C. We suggest thatthis peptide is a very good starting building block for engineering new bioactive molecules by graftingdifferent active or recognition sites onto it. The 21-residue peptide was further shortened by removingtwo residues in the loop connecting the second and third cysteines. This peptide exhibited a less well-defined conformation and is less stable by about 1 kcal mol-1, but it might be useful if a higher flexibilityis desired. The lower stability of the 21-residue peptide is supposed to result from inadequate lengths ofsegments connecting the first three cysteines, thus providing new insights into the structural determinantsof the CSB motif.