Identification of a small RNA within the pdh gene cluster of Mycoplasma pneumoniae and Mycoplasma genitalium

A highly abundant and heterogenous small RNA about 205 to 210 bases long na med MP200 RNA has been identified in Mycoplasma pneumoniae. It was localize d on the genome within a 319-bp-long intergenic space of the pyruvate dehyd rogenase (pdh) gene cluster. A database search at the DNA level revealed th e highest similarity to a sequence located within the pdh gene cluster of M ycoplasma genitalium that was also shown to be transcribed into two abundan t, but smaller RNAs than the ones in Mycoplasma pneumoniae. The RNAs from b oth M. pneumoniae and M. genitalium have the potential to code for cysteine -rich 29- and 23-amino-acid-long peptides, but so far, these peptides have not been identified experimentally in bacterial protein extracts.