The crystal structure of the Rev binding element of HIV-1 reveals novel base pairing and conformational variability

摘要: The crystal and molecular structure of an RNA duplex corresponding to the high affinity Rev protein binding element (RBE) has been determined at 2.1-A resolution. Four unique duplexes are present in crystal, comprising two structural variants. In each duplex, double helix consists annealed 12-mer 14-mer that form asymmetric internal loop consisting G-G G-A noncanonical base pairs a flipped-out uridine. strand A-form conformation, whereas is distorted accommodate bulges pairing. contrast NMR model unbound RBE, pair with N2-N7 N1-O6 hydrogen bonding, formed helix. pairing agrees one variant, but forms novel water-mediated other. A backbone flip reorientation required assume RBE conformation complex between peptide.