Mutations in the QVVAG region of the cysteine proteinase inhibitor stefin B.
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.
Jerala
R
R
Department of Biochemistry, Jozef Stefan Institute, Ljubljana, Yugoslavia.
Trstenjak-Prebanda
M
M
Kroon-Zitko
L
L
Lenarcic
B
B
Turk
V
V
D001483:Base Sequence; D003001:Cloning, Molecular; D055313:Cystatin B; D015891:Cystatins / Q000096:biosynthesis / Q000235:genetics*; D015853:Cysteine Proteinase Inhibitors; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010206:Papain / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics
C524994:CSTB protein, human; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D011994:Recombinant Proteins; D055313:Cystatin B; D010206:Papain