FIG. 12.

The structure of the type B PutA SmPutA (PDB code 5KF6). (A) Structure of the C-terminal ALDHSF domain, along with a topology diagram of the Rossmann subdomain. (B) Structure of the protomer. The arm, α-domain, PRODH barrel, and linker are colored cyan (“PRODH module”). The GSALDH NAD⁺-binding and catalytic domains are colored red and blue, respectively. The C-terminal ALDHSF domain is colored gold. The pink surface represents the substrate-channeling tunnel. The asterisks denote the active sites. (C) Cartoon and surface representations of the dimer. On the left, the domains are colored as in (B). On the right, the two chains have different colors. (D) The separated protomers of the SmPutA dimer. The interaction surfaces are color coded according to modules/domains as in (B) PRODH module, cyan; NAD⁺ binding, red; GSALDH catalytic, blue; C-terminal ALDHSF, gold. Figure adapted from Luo et al. (71). SmPutA, Sinorhizobium meliloti proline utilization A. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars