Sequence and expression of the Escherichia coli K1 neuC gene product.

The nucleotide sequence of the neuC gene of the Escherichia coli K1 capsule gene cluster encodes a protein with a predicted molecular weight of 44,210 containing 391 amino acids. A chimeric protein with beta-galactosidase fused to the carboxy terminus of the neuC gene product (P7) was constructed and purified. Its amino-terminal sequence confirmed the prediction from the nucleotide sequence that the neuC gene overlaps the distal end of the neuA gene by a single base pair. Both the neuA and neuC genes are coexpressed under the control of a single upstream T7 or tac promoter, suggesting that neuA and neuC are part of an operon.