Mediates bacterial resistance to the antibiotics streptomycin and spectinomycin, does not confer resistance to kanamycin (PubMed:26527143). Binds ATP first, then antibiotic (PubMed:26527143, PubMed:29871922). ATP + streptomycin = 3''-O-adenylylstreptomycin + diphosphate ATP + spectinomycin = 9-O-adenylylspectinomycin + diphosphate Monomer. Induced by growth in minimal media (at protein level). Under positive control of the stringent response regulator guanosine 3',5'-bis(diphosphate) (ppGpp). Has an N-terminal adenylyltranferase and a C-terminal helical domain, with an ATP-binding cleft between them (PubMed:26527143, PubMed:29871922). Upon ATP binding the two domains reposition, antibiotics bind in this cleft (PubMed:29871922). Loss of streptomycin and spectinomycin resistance.