Figure 4.

C-Methylation of Gentamicin A to Gentamicin X2 Catalyzed by GenD1

LC-ESI-HRMS selective ion monitoring was carried out on (A) [M + H]⁺m/z 483 of the product of GenD1-catalyzed methylation of gentamicin A (6); (B) [M + H]⁺m/z 252 of coproduced 5′-dAdo (20); (C) MS and MS/MS spectra of gentamicin A (6); (D) MS and MS/MS spectra of gentamicin X2 (4). Different high-performance liquid chromatography conditions were used for detection of gentamicin X2 (4) and 5′-dAdo (20), respectively, as described in Supplemental Experimental Procedures. 5′-dAdo, 5′-deoxyadenosine; BV, benzyl viologen; MV, methyl viologen.