Figure 2

The three-dimensional structure of the M. tuberculosis CysA2 (PDB code 3HWI). (a) Cartoon representation of CysA2 structure consisting of 12 α-helices and two β-sheets, respectively, with 4 and 5 strands in the N and C terminal domains. The position of the two signatures for rhodaneses, in the N and C domains, are shown in green and orange, respectively. The residues from active site are colored in blue and the catalytic cysteine (C233) in yellow. A detailed view and position of the residues (²³³CRIGER²³⁸) is also showed in sticks. (b) The amino acid sequence of M. tuberculosis CysA2 was aligned and compared with TSTs (I) and MSTs (II) described in the literature. The rhodanese signatures present in N (green) and C (orange) domains are conserved in all sequences. The residues of CysA2 active site are closely related to TSTs [CR(K/Y)] and not MSTs CG(S/T). TSTs: 3HWI_Mtu_CysA2: M. tuberculosis CysA2, 3AAX_Mtu_CysA3: M. tuberculosis CysA3, 3HZU_Mtu_SseA: M. tuberculosis SseA, 3P3A_Mth_TST: Mycobacterium thermoresistibile TST, 1E0C_Avi_RhdA: Azotobacter vinelandii RhdA, 2ORA_Bta: Bos taurus Rhobov. MSTs: 1OKG_Lma_MST: Leishmania major LmMST, 3UTN_Sce_TUM1: Saccharomyces cerevisiae TUM1, 1URH_Eco_SseA: Escherichia coli SseA and 3OLH_Hsa_MST: Homo sapiens HsMST.