RT Journal Article SR Electronic(1) A1 Lankinen, Hilkka A1 McLauchlan, John A1 Weir, Malcolm A1 Furlong, Judy A1 Conner, Joe A1 McGarrity, Anne A1 Mistry, Anil A1 Clements, J. Barklie A1 Marsden, Howard S.YR 1991 T1 Purification and characterization of the herpes simplex virus type 1 ribonucleotide reductase small subunit following expression in Escherichia coli JF Journal of General Virology, VO 72 IS 6 SP 1383 OP 1392 DO https://doi.org/10.1099/0022-1317-72-6-1383 PB Microbiology Society, SN 1465-2099, AB 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., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-72-6-1383