Discovery and investigation of misincorporation of serine at asparagine positions in recombinant proteins expressed in Chinese hamster ovary cells.

ABSTRACT: Misincorporation of amino acids in proteins expressed in Escherichia coli has been well documented but not in proteins expressed in mammalian cells under normal recombinant protein production conditions. Here we report for the first time that Ser can be incorporated at Asn positions in proteins expressed in Chinese hamster ovary cells. This misincorporation was discovered as a result of intact mass measurement, peptide mapping analysis, and tandem mass spectroscopy sequencing. Our analyses showed that the substitution was not related to specific protein molecules or DNA codons and was not site-specific. We believe that the incorporation of Ser at sites coded for Asn was due to mischarging of tRNA(Asn) rather than to codon misreading. The rationale for substitution of Asn by Ser and not by

SUBMITTER: Wen D 

PROVIDER: S-EPMC2781684 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature