FIG 4.

Computational genomics of OPX proteins. (A) Length distribution of 2,749 OPX proteins. OPX proteins encoded within a distance of five genes of a gene encoding a β-barrel protein are shown in dark gray, and the remaining OPX proteins are in light gray. OPX proteins discussed in the text are highlighted in blue. The 1,230 short OPX proteins are indicated based on the upper size limit of ≤280 aa. (B) Length distribution of OPX proteins of ≤280 aa. Four hundred fifty-three OPX proteins with a coupled β-barrel protein and no C-terminal α-helix are in dark gray; 535 OPX proteins with no coupled β-barrel protein but a C-terminal α-helix are in red. Proteins not matching these criteria are in light gray. (C) Maximum-likelihood phylogenetic tree built from the PES motif of the 2,749 OPX proteins. The inner ring is colored based on NCBI taxonomy (https://www.ncbi.nlm.nih.gov/taxonomy/). PVC, FCB, and Terrabacteria are superphyla, and the phylum Proteobacteria is divided into classes. #, this phylum contains an OPX protein(s) of ≤280 aa coupled to a β-barrel protein(s). The second ring indicates the pathway assigned to individual OPX proteins. The third ring indicates, in dark blue, coupling with a β-barrel protein. The fourth ring indicates, in orange, OPX proteins of ≤280 aa. The fifth ring indicates, in black, whether an OPX protein has a C-terminal α-helix. (D) AlphaFold models of indicated OPX proteins. Domains are labeled D1 and D2 and colored according to the homologous domains in Wza (Fig. 2A). Model rank 1 is shown for all structures.