Structural alignments of MIP to highlight noticeable differences in glycerol facilitators <i>versus</i> standard AQP.

<p><b>(A)</b> Structural alignment of different MIP based on the coordinates of resolved structures made with MulPBA on a narrow but still representative sample of MIP of different classes from different kingdoms. The name of the proteins and their relative pdb code is written with distinctive colors on the left of the alignment, itself colored by the Taylor color code in Jalview. A conservation threshold of 50% is applied to highlight the conservation by groups. From this comparison emerges the particular meaning of the conserved GlFp motif NPARD: the conserved negatively-charged residue aspartate makes a salt bridge with an equally conserved residue at exactly one α-turn from it. This bridge quenches both charges by mutual neutralization, allowing their presence in a quite hydrophobic environment for folding purposes (first quarter of α-6). <b>(B)</b> PyMOL scene of the superimposition results from mulPBA displayed as a wireframe diagram of the main chain colored with respect to the sequence name coloring. The channel is shown as a transparent volume to materialize the localization. The sidechain of the conserved arginine from the NPAR motif is shown as sticks, as also are both charged residues occurring only in the GlFp proteins (light and dark red). A red arrow shows the relative displacement (concomitant with this type of electrostatic bridge within the short α-helix of loop E) responsible, at least in part, for a larger pore aperture at its constriction site. Only the NPA α-helices are shown as transparent colored coils (<b>C)</b> Summary of the superimposition score from mulPBA. <b>(D)</b> Structural alignment of MIP from the <i>T</i>. <i>harzianum</i> strain CBS 226.95 homologous to those expressed from <i>Ths97</i> and based on the coordinates of good quality I-Tasser homology models. The MSA is colored by the Taylor color code in Jalview. On the left, the Newick tree established by mulPBA is given showing the relative proximity of both XIP-488926 and AQP-98742 members on one side, and both "other AQGP"-92358 and Fsp-like 90014 members on the other side. Models are consistent with previous data obtained on experimental structures. A conservation threshold of 50% is also applied to highlight the conservation by groups.