An efficient fusion expression system for protein and peptide overexpression in Escherichia coli and NMR sample preparation.

An efficient fusion expression system with a small fusion partner, His6-tagged N-terminal fragment of staphylococcal nuclease R, has been constructed and tested with two genes. The results show that the system is not only suitable for overexpression of small proteins and peptides but simplifies purification of target proteins and peptides. The study also provides a practical method for preparation of isotope-labeled protein sample for NMR analysis.