RT Journal Article SR Electronic T1 Structural characterization of an RNA bound antiterminator protein reveal a successive binding mode JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.09.27.315978 DO 10.1101/2020.09.27.315978 A1 James L. Walshe A1 Karishma Patel A1 Sandro F. Ataide YR 2020 UL http://biorxiv.org/content/early/2020/09/28/2020.09.27.315978.abstract AB In bacteria, rho-independent termination occurs through the formation of an intrinsic RNA terminator loop, which disrupts the RNA polymerase elongation complex, resulting in dissociation from the DNA template. ANTAR domains are a class of antiterminator that bind and stabilise mutually exclusive dual hexaloop motifs within the nascent RNA chain to prevent terminator loop formation. We have determined the structures of the dimeric ANTAR domain protein EutV, from E. faecialis, both in the absence of and in complex with the dual hexaloop RNA target. The structures illustrate the conformational changes that occur upon RNA binding and reveal the molecular interactions between the ANTAR domains and RNA are restricted to a single hexaloop of the motif. Our findings thereby redefine the minimal ANTAR domain binding motif to a single hexaloop and revise the current model for ANTAR-mediated antitermination. These insights will inform and facilitate the discovery of novel ANTAR domain RNA targets.Competing Interest StatementThe authors have declared no competing interest.