Codon optimization of the gene encoding a domain from human type 1 neurofibromin protein results in a threefold improvement in expression level in Escherichia coli.

An internal domain from the human type 1 neurofibromin has previously been expressed in Escherichia coli as a fusion with gluthathione S-transferase (GST). The expression level of this protein was lower than expected and so a gene was constructed using the distribution of codons found in highly expressed E. coli proteins. Codons were assigned using a Microsoft Visual Basic computer program to give a distribution similar to those found in genes which are highly expressed in E. coli. The optimized gene was then cloned back into the same GST fusion plasmid and it was found that the expression of soluble protein had increased threefold.