passages.id: split_6_test_3257_passage
passages.type: progene_text
passages.text: The operons ars1 and ars2 are located some distance from each other in the bacterial chromosome , but they are both composed of genes encoding a regulatory protein ( arsR ) , an arsenite permease ( arsB ) , and an arsenate reductase ( arsC ) ; operon ars1 contains an additional arsenate reductase gene ( arsC1' ) located immediately downstream from arsC1 .