Identification of a novel aminoglycoside -nucleotidyltransferase AadA33 in .

A novel chromosome-encoded aminoglycoside -nucleotidyltransferase AadA33 was identified in strain P13. The AadA33 shares the highest amino acid identity of 51.28% with the function characterized AadA31. Antibiotic susceptibility testing and enzyme kinetics analysis revealed that the function of AadA33 is to mediate spectinomycin and streptomycin resistance. The recombinant strain harboring (pUCP20-/ DH5α) displayed >256- and 128-fold increases in the minimum inhibitory concentration levels to spectinomycin and streptomycin, respectively, compared with the control strains pUCP20/DH5α. Enzyme kinetic parameters manifested the substrate of AadA33 including spectinomycin and streptomycin, with / of 3.28 × 10 (M s) and 3.37 × 10 (M s), respectively. Bioinformatics analysis revealed its structural mechanism of antimicrobial resistance, genetic context, and phylogenetic relationship with other aminoglycoside -nucleotidyltransferases. This study of AadA33 contributed to understanding the function and resistance mechanism of aminoglycoside -nucleotidyltransferase.