FIG 2.

Evolutionary relationships of 5′-methylthioadenosine/S-adenosylhomocysteine deaminases to M. jannaschii DadD. MtaD represents the homologs that do not have confirmed gene annotation; those confirmed are MTAD, SAHD, MtaD, and DadD. The organisms in the top bracket represent those that have the closest homology to MTAD and likely use MTA as their preferred substrate. The organisms in the middle bracket share homology with SAHD and likely use SAH as their preferred substrate. Those in the bottom bracket share homology with DadD of M. jannaschii (highlighted in the box), and we propose the use of 5′-dA as their preferred substrate. The accession numbers for the proteins used in the construction of the tree in order from top to bottom are as follows: B6YUF8, Q5JER0, O66851, A6UUG9, I9MDY4, O27549, Q4K8M5, A6V2Q5, G0PU20, M1Z1T6, Q9KC82, D3DYL9, Q8TYD4, Q2RJW1, B1BCH5, A4FW32, F2KTB3, Q8U0P7, D5VT65, Q9X034, Q58936, and C7P5A2.