label: a cytidine in rRNA + S-adenosyl-L-methionine = a 5-methylcytidine in rRNA + S-adenosyl-L-homocysteine + H(+)
label_lc: a cytidine in rrna + s-adenosyl-l-methionine = a 5-methylcytidine in rrna + s-adenosyl-l-homocysteine + h(+)