Multifunctional protein that promotes group II intron splicing and mobility by acting both on RNA and DNA. It has three activities: reverse transcriptase (RT) for intron duplication, maturase to promote splicing, and DNA endonuclease for site-specific cleavage of recipient alleles. The intron-encoded protein promotes splicing by facilitating the formation of the catalytically active structure of the intron RNA. After splicing, the protein remains bound to the excised intron lariat RNA, forming ribonucleoprotein particles, and cleaving the antisense strand of the recipient DNA in the 3' exon. After DNA cleavage, retrohoming occurs by a target DNA-primed reverse transcription of the intron RNA that had reverse spliced into the sense strand of the recipient DNA. It also contributes to the recognition of the DNA target site and acts as a repressor of its own translation. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Homodimer. Mobile group II introns can be retargeted and used for highly specific chromosomal gene disruption in bacteria. Could be useful for genetic engineering and functional genomics in a wide variety of bacteria. The correct folding of LtrA seems to be facilitated by binding to the unspliced precursor or intron RNA. RNA would serve in part as a chaperone that promotes folding of the protein into an active conformation. Purified protein lacks endonuclease activity unless complexed with intron lariat RNA. It may preferentially function in cis by binding to the intron RNA from which it was translated. In the N-terminal section; belongs to the bacterial reverse transcriptase family.