FIG. 1.

Organization of the class Ib and class III RNR genes in S. aureus and other gram-positive bacteria. (A) Class Ib RNR genes. Gene designations: nrdH, homolog of E. coli nrdH, which encodes a redoxin protein; nrdI, homolog of E. coli nrdI, which encodes a protein-stimulating class Ib RNR activity; nrdE and bnrdE, homologs of E. coli nrdE, which encodes the α subunit of class Ib RNR; nrdF and bnrdF, homologs of E. coli nrdF, which encodes the β subunit of class Ib RNR; ymzA, gene encoding a hypothetical protein containing a putative redox motif; grxS, gene encoding a glutaredoxin-like protein; orf1, putative ORF (see the text); other ORFs encode hypothetical proteins of unknown function. The positions of introns and regions encoding inteins are shown as grey boxes. (B) Class III RNR genes. Gene designations: nrdD, homolog of E. coli nrdD, which encodes the α subunit of class III RNR; nrdG, homolog of E. coli nrdG, which encodes the activating β protein of class III RNR. The directions of ORFs are indicated by arrows. See the text for other details.