The MatK Gene of Spiranthes Sinensis Encodes a Maturase Involved in Multiple Biological Processes

Abstract

The maturase K gene (matK) encodes the only hypothetical group II intron maturase in the chloroplast genome. To investigate the molecular characteristics and functions of matK gene in Spiranthes sinensis (SsmatK), the Ssmatk protein was systematically analyzed by bioinformatics. The results showed that SsmatK gene encodes an unstable hydrophilic protein located in chloroplast. Sequence alignment showed that SsmatK protein contained a domain X region, which was a specific region of group II intron encoding maturase. Phylogenetic tree analysis showed that SsmatK protein is most closely related to the matK proteins of Schiedeella garayana and Schiedeella romeroana. Post-translational modification analysis revealed that SsmatK protein had 55 phosphorylation sites and 3 glycosylation sites. The result of tertiary structure showed that two potential phosphorylation sites Ser446 and Thr450 in the essential SCARTLARKHK sequence may be two important synergistic sites for SsmatK protein function. Molecular functional analysis of the gene ontology showed that SsmatK protein was defined as binding activity, including specific binding to other proteins, organic cyclic compounds, nucleic acids, heterocyclic compounds and RNA molecules. Biological processes analysis of gene ontology further revealed that SsmatK was mainly involved in metabolic processes, gene expression and RNA processing. The above results suggest that the SsmatK gene located within the chloroplast group II intron encodes a highly conserved maturase and participates in a variety of biological processes. Therefore, strengthening the identification of potential coding genes in chloroplast genome will help to enrich our understanding of the complexity of transcriptional genes.