passages.id: split_4_test_3348_passage
passages.type: progene_text
passages.text: Here , we analysed the E.coli rRNAs by matrix assisted laser desorption / ionization mass spectrometry and show that inactivation of the yebU gene leads to loss of methylation at C1407 in 16 S rRNA , but does not interfere with methylation at C1962 in 23 S rRNA .