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.
Department of Biochemistry, Jozef Stefan Institute, Ljubljana, Yugoslavia.
R
R
Jerala
M
M
Trstenjak-Prebanda
L
L
Kroon-Zitko
B
B
Lenarcic
V
V
Turk
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