Structural highlights
FunctionORN_VIBCH 3'-to-5' exoribonuclease specific for small oligoribonucleotides.[HAMAP-Rule:MF_00045] Publication Abstract from PubMedOligoribonuclease (Orn), a member of the DEDDh superfamily, can hydrolyse 2-5 nt nanoRNAs to mononucleotides. It is involved in maintaining the intracellular levels of RNA, c-di-GMP signalling and transcription initiation in many bacterial species. Here, the crystal structure of Orn from Vibrio cholerae O1 El Tor (VcOrn) is reported at a resolution of 1.7 A. VcOrn, which consists of nine alpha-helices and six beta-strands, crystallizes with a single monomer in the asymmetric unit but forms a homodimer via crystallographic twofold symmetry. Electron density is observed in the active pocket that corresponds to an intersubunit N-terminal expression tag with sequence GPLGSHHH. The positively charged N-terminal tag binds in the negatively charged nucleotide-binding pocket with a buried surface area of approximately 500 A(2). The N-terminal tag interacts with VcOrn via pi-pi stacking with two conserved residues involved in nucleotide binding, as well as via salt bridges and hydrogen bonds. The structure reported here reveals that the active pocket can accommodate polypeptides in addition to nucleotides, thus providing an important starting point for investigation into substrate modification and inhibitor design targeting VcOrn. Crystal structure of oligoribonuclease from Vibrio cholerae O1 El Tor with bound peptide.,Zhang J, Sun L, Zhang Q, Bartlam M Acta Crystallogr F Struct Biol Commun. 2021 Dec 1;77(Pt 12):437-443. doi:, 10.1107/S2053230X21011043. Epub 2021 Nov 11. PMID:34866598[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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