RNA 2'-O-methyltransferase involved in the maturation of rRNA and in the biogenesis of ribosomal subunits. a ribonucleotide in rRNA + S-adenosyl-L-methionine = a 2'-O-methylribonucleotide in rRNA + H(+) + S-adenosyl-L-homocysteine Belongs to the class I-like SAM-binding methyltransferase superfamily. RNA methyltransferase RlmE family. SPB1 subfamily.