TY - JOUR
AU - Narula,, S.K.
AB - Abstract We have identified a mutation of human gamma-interferon (IFNγ) causing a temperature-sensitive phenotype. We used a randomized oligonucleotide to mutagenize a synthetic human IFNγ gene, then screened the resulting mutants produced in Escherichia coli for proteins with altered biological activity. One mutant protein selected for detailed characterization exhibited < 0.3% of the specific biological activity of native IFNγ in an antiviral activity assay performed at 37°C. However, the protein bound the human IFNγ receptor with native efficiency at 4°C. Sequencing the plasmid DNA encoding this protein snowed that the mutation changed the lysine residue at amino acid 43 to glutamic acid (IFNγ/K43E). Site-specific mutagenesis at amino acid 43 showed that this protein's phenotype resulted from positioning a negative charge at position 43. Structural characterization of IFNγ/K43E using CD demonstrated that the protein had native conformation at 25°C, but assumed an altered conformation at 37°C. IFNγ/K43E in this altered conformation bound poorly to the IFNγ receptor at 37°C, providing a rationale for the mutant's decreased antiviral activity. This content is only available as a PDF. © Oxford University Press
TI - A point mutation that decreases the thermal stability of human interferon γ
JF - Protein Engineering, Design and Selection
DO - 10.1093/protein/5.3.249
DA - 1992-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/a-point-mutation-that-decreases-the-thermal-stability-of-human-kd0Tz0n33x
SP - 249
EP - 252
VL - 5
IS - 3
DP - DeepDyve
ER -