Specifically methylates the N(7) position of guanine 1405 in 16S rRNA (By similarity). Confers resistance to aminoglycosides. guanosine(1405) in 16S rRNA + S-adenosyl-L-methionine = N(7)-methylguanosine(1405) in 16S rRNA + S-adenosyl-L-homocysteine Protects M.rosea, which is an antibiotic-producing bacterium, against self-intoxication. Belongs to the methyltransferase superfamily. Aminoglycoside resistance family.