Transfer RNA recognition by class I lysyl-tRNA synthetase from the Lyme disease pathogen Borrelia burgdorferi

Borrelia burgdorferi and other spirochetes contain a class I lysyl-tRNA synthetase (LysRS), in contrast to most eubacteria that have a canonical class II LysRS. We analyzed tRNA(Lys) recognition by B. burgdorferi LysRS, using two complementary approaches. First, the nucleotides of B. burgdorferi tRNA(Lys) in contact with B. burgdorferi LysRS were determined by enzymatic footprinting experiments. Second, the kinetic parameters for a series of variants of the B. burgdorferi tRNA(Lys) were then determined during aminoacylation by B. burgdorferi LysRS. The identity elements were found to be mostly located in the anticodon and in the acceptor stem. Transplantation of the identified identity elements into the Escherichia coli tRNA(Asp) scaffold endowed lysylation activity on the resulting chimera, indicating that a functional B. burgdorferi lysine tRNA identity set had been determined.