Crystallization and preliminary X-ray crystallographic analysis of a bacterial Asn-transamidosome

摘要

Most canonical aminoacyl-tRNAs are synthesized directly by their cognate aminoacyl-tRNA synthetases (aaRSs), but glutaminyl-tRNA^Gln and asparaginyl-tRNA^Asn are synthesized indirectly by two-step processes. These processes are catalyzed by the transamidosome, a large ribonucleoprotein particle composed of GatA, GatB, GatC, aaRS and tRNA. In this study, the Asn-transamidosome from Pseudomonas aeruginosa was reconstructed and crystallized by mixing purified GatCAB complex, AspRS and tRNA^Asn. The crystal of the Asn-transamidosome belonged to space group P21, with unit-cell parameters a = 93.3, b = 186.0, c = 287.8 Å, β = 93.3°, and diffracted to 3.73 Å resolution. Preliminary X-ray crystallographic analysis showed that the asymmetric unit contained two Asn-transamidosomes, each composed of two GatCABs, one AspRS dimer and two tRNA^Asns, indicating that the construction of the current Asn-transamidosome differs from that of Thermus thermophilus.