title: A comparison of group II introns of plastid tRNALysUUU genes encoding maturase protein.
abstract: All higher plant plastid genomes have six classes of tRNA genes containing introns. One of those is the tRNALysUUU gene, which encodes maturase protein. In the case of liverwort species from the genus Porella and mosses from the genus Plagiomnium, the maturase coding gene (matK) represents a truncated form of other plant matK genes: several subdomains of the reverse transcriptase-like domain and so-called domain X are not present in these ORFs. These ORFs probably represent pseudogenes of the matK gene. The analysis of codon usage within the matK gene revealed the presence of strong A/T pressure. The use of codons with the third letter being U or A varies from 71-93%. The comparison of maturase amino acid sequences at the family level shows a high identity between species. However, when liverwort and angiosperm maturase sequences are compared, the percentage of identity drops dramatically. The calculated values of the number of nucleotide substitutions vary considerably, even when liverwort species are compared pairwise. The phenetic tree of relationships between plant species on the basis of tRNALysUUU intron sequences concur with the generally accepted plant phylogeny.
authors.affiliation: Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Miedzychodzka 5, 60-371 Poznań, Poland.
authors.forename: Kamila
authors.initials: K
authors.lastname: Jankowiak
authors.forename: Joanna
authors.initials: J
authors.lastname: Lesicka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pacak
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Rybarczyk
authors.forename: Zofia
authors.initials: Z
authors.lastname: Szweykowska-Kulińska
mesh_terms: D000465:Algorithms; D003062:Codon; D030561:Databases, Nucleic Acid; D004722:Endoribonucleases / Q000235:genetics*; D035926:Hepatophyta / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009713:Nucleotidyltransferases / Q000235:genetics*; D016366:Open Reading Frames; D018087:Plastids / Q000235:genetics*; D012357:RNA, Transfer, Lys / Q000737:chemistry / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D003062:Codon; D012357:RNA, Transfer, Lys; D009713:Nucleotidyltransferases; C034038:mRNA maturase; D004722:Endoribonucleases