passages.id: split_8_test_2562_passage
passages.type: progene_text
passages.text: Mutants F74A , D75A , M78A , D79A and Q85A appear to define a surface required for protein - protein interaction with RNA polymerase specifically at class II promoters because these positive control mutants bind and bend DNA normally but are defective in activation of class II promoters but not class I promoters .