This entry represents a zinc ribbon domain found at the C-terminal of topoisomerase I from bacteria (it corresponds to D6 described in [1]. Topoisomerase I has an essential function in preventing hypernegative supercoiling of DNA. The C-terminal domains bind ssDNA to recognise the accumulation of negative supercoils in duplex DNA [1].

1: Structural basis for suppression of hypernegative DNA supercoiling by E. coli topoisomerase I. Tan K, Zhou Q, Cheng B, Zhang Z, Joachimiak A, Tse-Dinh YC; Nucleic Acids Res. 2015;43:11031-11046. PMID:26490962