Erratum: Misincorporation of nucleotides opposite five-membered exocyclic ring guanine derivatives by Escherichia colli polymerases in vitro and in vivo: 1,N2-ethenoguanine, 5,6,7,9-tetrahydro-9-oxoimidazo[1,2- a]purine, and 5,6,7,9-tetrahydro-7-hydroxy-9-oxoimidazo[1,2-a]purine (Biochemistry (April 14, 1998) 37:15 (5184-5193))