InterPro domain: IPR024942

Group II introns are widespread in plant cell organelles [ 1 ]. In vivo, most plant group II introns do not self-splice, but require the assistance of proteinaceous splicing factors, known as maturases. In higher plants, maturases are encoded for in the nuclear genes [ 2 ], but are otherwise encoded by organellar introns.

The N-terminal domain of MatK appears to be a divergent reverse transcriptase domain that has lost most of the conserved sequence motifs typical of functional reverse transcriptases [ 3 ]. The function of this domain is not known, but it may be important in RNA splicing.

Maturase MatK is usually encoded in the trnK tRNA gene intron, and probably assists in splicing its own and other chloroplast group II introns.

1. Evolutionary origin of a plant mitochondrial group II intron from a reverse transcriptase/maturase-encoding ancestor. J. Plant Res. 119, 363-71
2. Putative proteins related to group II intron reverse transcriptase/maturases are encoded by nuclear genes in higher plants. Nucleic Acids Res. 31, 647-52
3. Evolutionary relationships among group II intron-encoded proteins and identification of a conserved domain that may be related to maturase function. Nucleic Acids Res. 21, 4991-7