(A) A multiple sequence alignment of CysRS of Hh (Halobacterium species NRC-1, also known as H. halobium), Mm (Methanococcus maripaludis), Af (Archaeoglobus fulgidus), Pa (Pyrococcus abyssi), Bs (Bacillus subtilis), Sa (Staphylococcus aureus), Aa (Aquifex aeolicus), Mt (Mycobacterium tuberculosis), Hi (Haemophilus influenzae), Ec (Escherichia coli), Hs (Homo sapiens), and Sc (Saccharomyces cerevisiae), showing division of the bacterial and eukaryotic type. (B) An SDS-PAGE analysis of expression of Halobacterium sp. NRC-1 CysRS in E. coli and purification by a metal-affinity resin. (Lane 1) Molecular markers; (lane 2) whole cell lysate before induction with IPTG; (lane 3) whole cell lysate after induction; (lane 4) the soluble fraction of the cell lysate; (lane 5) the insoluble fraction of the cell lysate; (lane 6) the bound fraction of the metal affinity resin; (lane 7) the reconstituted CysRS, and (lane 8) the cloned and expressed E. coli CysRS as a marker.