Maturase K (matK) is a plant plastidial gene.[1] The protein it encodes is an organelle intron maturase, a protein that splicesGroup II introns. It is essential for in vivo splicing of Group II introns.[2] Amongst other maturases, this protein retains only a well conserved domain X and remnants of a reverse transcriptase domain.[3]
LtrA, an open reading frame found in the Lactococcus lactis group II introns LtrB. It is an intron-encoded protein, with three subdomains, one of which is a reverse-transcriptase/maturase.