FIG 3 .

DvH-MO SNP mutation in a conserved α-helix of the ABC transporter DVU1017 of a putative type I secretion system (T1SS). (a) Cartoon representation of a T1SS complex comprised of three subunits: the outer membrane protein, the membrane fusion protein (MFP), and the ABC transporter (16). The red X marks the subunit with the SNP found in planktonic DvH-MO. (b) Sequence and amino acid changes found at the 635th residue of the DVU1017 protein, the predicted ABC transporter. Shown is a cartoon representation of the possible proline kink in this predicted α-helix and the change in direction that the adjacent amino acids are facing (depicted by shading). (c) Secondary structure prediction of the 622- to 650-amino-acid region of DVU1017 that encompasses residue 635. Prediction was with PSIPRED. Pink cylinders denote a helical structure, H, that is flanked by coils, C. The PSIPRED confidence of the prediction is shown along the top. (d) A sequence logo generated from an alignment of the DVU1017 amino acid sequence to the top 475 BLAST hits, excluding other Desulfovibrio spp., shows the conservation of Ala at 635. The frequency of amino acid is depicted by the size of the letter in bits. The red box highlights Ala₆₃₅ in both panels c and d.