Mutations in the QVVAG region of the cysteine proteinase inhibitor stefin B.

@article{Jerala1990MutationsIT,
  title={Mutations in the QVVAG region of the cysteine proteinase inhibitor stefin B.},
  author={Roman Jerala and M Trstenjak-Prebanda and Louise Kroon-Zitko and Brigita Lenar{\vc}i{\vc} and Vito Turk},
  journal={Biological chemistry Hoppe-Seyler},
  year={1990},
  volume={371 Suppl},
  pages={157-60}
}
Variants of human stefin B were constructed by cassette mutagenesis. Val47 as the constituent of highly conserved QVVAG sequence was substituted by hydrophobic amino acids of increasing size - Ala, Ile and Phe. Recombinant proteins were expressed in E. coli and Ki values for papain were determined. Substitutions did not cause a major change in Ki value and we conclude that the interaction with the proteinases is not the reason for the conservation of the pentapeptide.