Physical evidence for a domain structure in Escherichia coli 5 S RNA

The downfield (9.5–15 ppm) proton spectra of a RNase A‐resistant fragment of 5 S RNA and of its parent molecule are compared. The data show that the hydrogen‐bonded structure of the fragment is the same as that of the corresponding sequences of A form 5 S RNA. The fragment must constitute a stable structural domain of 5 S RNA.