<p>This clade of sequences is closely related to MiaB, a modifier of isopentenylated adenosine-37 of certain eukaryotic and bacterial tRNAs (see <db_xref db="INTERPRO" dbkey="IPR006463"/>). Sequence alignments suggest that these sequences perform the same chemical transformation as MiaB, perhaps on a different (or differently modified) tRNA base substrate. This clade represents a subfamily that spans low GC Gram-positive bacteria, alpha and epsilon proteobacteria, Campylobacter, Porphyromonas, Aquifex, Thermotoga, Chlamydia, Treponema and Fusobacterium [<cite idref="PUB00009731"/>, <cite idref="PUB00009728"/>, <cite idref="PUB00009729"/>].</p>