title: Crystal structures of a group II intron maturase reveal a missing link in spliceosome evolution.
abstract: Group II introns are self-splicing ribozymes that are essential in many organisms, and they have been hypothesized to share a common evolutionary ancestor with the spliceosome. Although structural similarity of RNA components supports this connection, it is of interest to determine whether associated protein factors also share an evolutionary heritage. Here we present the crystal structures of reverse transcriptase (RT) domains from two group II intron-encoded proteins (maturases) from Roseburia intestinalis and Eubacterium rectale, obtained at 1.2-Å and 2.1-Å resolution, respectively. These domains are more similar in architecture to the spliceosomal Prp8 RT-like domain than to any other RTs, and they share substantial similarity with flaviviral RNA polymerases. The RT domain itself is sufficient for binding intron RNA with high affinity and specificity, and it is contained within an active RT enzyme. These studies provide a foundation for understanding structure-function relationships within group II intron-maturase complexes.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.|Department of Chemistry, Yale University, New Haven, Connecticut, USA.|Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
authors.forename: Anna Marie
authors.initials: AM
authors.lastname: Pyle
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D000068016:Eubacteriales / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D007438:Introns; D008958:Models, Molecular; D000072417:Protein Domains; D055503:Protein Multimerization; D012329:RNA, Bacterial / Q000378:metabolism; D044563:RNA, Ribosomal, Self-Splicing / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry* / Q000378:metabolism; D017381:Spliceosomes / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D044563:RNA, Ribosomal, Self-Splicing; D012194:RNA-Directed DNA Polymerase