Cetus Corporation

Shi-da Yu Lu

David F Mark

Leo S Lin

Alice M Wang

Muteins of biologically active proteins such as IFN-.beta. and IL-2 in which cysteine residues that are not essential to biological activity have been deleted or replaced with other amino acids to eliminate sites for intermolecular crosslinking or incorrect intramolecular disulfide bridge formation. These muteins are made via bacterial expression of mutant genes that encode the muteins that have been synthesized from the genes for the parent proteins by oligonucleotide-directed mutagenesis.

Cysteine-depleted muteins of biologically active proteins

Structural genes, plasmids and transformed cells for producing cysteine

A modified IFN-.beta. is provided wherein the cysteine residue at position 17 is deleted and serine is substituted therefor. DNA sequences coding for the modified protein, nucleotide primers used for the mutagenesis, appropriate cloning vectors, host organisms transformed with the vectors, methods for the production and use of the modified IFN-.beta. (IFN-.beta..sub.ser17) are also provided. The specific activity of IFN-.beta..sub.ser17 is found to be substantially the same as that of native IFN-.beta..

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Oakland, CA, United States of America

Shi-da Yu Lu