CONFORMATIONAL-ANALYSIS OF COMPLEXES OF R NA-POLYMERASE FROM ESCHERICHIA-COLI WITH DNA

Conformational behaviour of T2 DNA during its complex formation with E . coli RNA polymerase was studied by spin label technique. T2 DNA was selectively modified at its readily melting AT-rich sites by bromoacet ooxypiperidine-1-oxyl-radical. Specific conformational changes are ind uced in DNA structure by RNA polymerase attachment. The changes are ob served under the conditions when open transcriptionally competent comp lexes are formed. The readily melting sites of T2 DNA were shown to be involved in the formation of functionally active promoters.