%0 Journal Article %A Lankinen, Hilkka %A McLauchlan, John %A Weir, Malcolm %A Furlong, Judy %A Conner, Joe %A McGarrity, Anne %A Mistry, Anil %A Clements, J. Barklie %A Marsden, Howard S. %T Purification and characterization of the herpes simplex virus type 1 ribonucleotide reductase small subunit following expression in Escherichia coli %D 1991 %J Journal of General Virology, %V 72 %N 6 %P 1383-1392 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-72-6-1383 %I Microbiology Society, %X The herpes simplex virus type 1 (HSV-1) gene encoding the ribonucleotide reductase (RR) small subunit (R2) was cloned as an unfused and intact open reading frame into a T7 RNA polymerase expression system in Escherichia coli. The expressed product was recovered from bacteria in soluble form and constituted 7% of the soluble protein. Protein purification yielded 3.5 mg of 95% pure R2 per litre of bacterial culture. The correct composition of the purified protein was verified by amino acid analysis and N-terminal sequencing. The isoelectric point of the protein was 5.3. Atomic emission spectroscopy indicated that the iron content of the E. coli-expressed R2 was 0.2 to 0.5 atoms of iron per R2 protomer as compared with a theoretical maximum value of 2. The E. coli-expressed HSV-1 R2 existed as a combination of a stable dimer and monomer. Combination of the E. coli-expressed R2 with the E. coli-expressed large subunit (R1) gave an active holoenzyme. Thus, the T7 expression system provides a rich source of enzymically active HSV-1 RR. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-72-6-1383