Structural and thermodynamic analysis of a conformationally strained circular permutant of barnase.

ABSTRACT: Circular permutation of a protein covalently links its original termini and creates new ends at another location. To maintain the stability of the permuted structure, the termini are typically bridged by a peptide long enough to span the original distance between them. Here, we take the opposite approach and employ a very short linker to introduce conformational strain into a protein by forcing its termini together. We join the N- and C-termini of the small ribonuclease barnase (normally 27.2 A distant) with a single Cys residue and introduce new termini at a surface loop, to create pBn. Compared to a similar variant permuted with an 18-residue linker, permutation with a single amino acid dramatically destabilizes barnase. Surprisingly, pBn is folded at 10 degrees C and possesses near wild

SUBMITTER: Butler JS 

PROVIDER: S-EPMC2756614 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature