Figure 4: Structural basis of ligand recognition by Mlp37.
From: Identification of a Vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants
Structures of the Mlp37p-ligand complexes (a–e). (a) Ribbon drawing of the Mlp37p-taurine complex monomer. The model is colour-coded from blue to red from the N- to the C-terminus, with labels showing the secondary structure elements. The bound taurine is shown as a ball-and-stick model. (b) The Mlp37p-taurine complex dimer. One subunit is shown in the same colour as (a), and the other is pale pink. It should be noted that the ribbon monomer image is rotated 90° from the one in A. (c–e) Close up view of the ligand-binding sites of the l-alanine complex (PDB ID: 3C8C) (c), the serine complex (d), and the taurine complex (e). Possible hydrogen bonds are indicated by dotted lines. (f) Effects of alanine substitutions of residues in pocket I on attractant responses. Capillary assays were carried out for Vmlp201 (∆mlp24 ∆mlp37) cells expressing wild-type or mutant Mlp37: none, open bars; wild-type, red; W141A, yellow; W147A, green; R152A, blue; W154A, cyan; Y170A, pink; D172A, purple; D201A, grey bars. Capillaries were filled with TMN buffer containing the indicated concentrations (1, 10 or 100 mM) of each attractant.
