Figure 4
From: Human Sialidase Neu3 is S-Acylated and Behaves Like an Integral Membrane Protein
Secondary structure prediction and homology modeling of Neu3. (a) Common folding topology for the β-propeller domain of viral, bacterial and Neu2 sialidases. The fold consists of six (I-VI) four-stranded (A–D) antiparallel β-sheets (arrows) arranged as the blades of a propeller, with the N- and C-termini close to each other. (b) Prediction of secondary structure elements in human Neu3 sequence using different servers available on-line. Predicted β-sheets and α-helix are shown in blue and magenta boxes, respectively. Some of the highly conserved active site residues are shown in bold and underlined, whereas the conserved F/YRIP motif near the N-terminus and the three Asp boxes are shown in black boxes. The orientation of the predicted antiparallel β-sheets is shown with arrows. (c) Homology model of Neu3 using Neu2 crystal structure as a template. The β-sheets of the β-propeller backbone are shown in the same colors as in Fig. 4a and b. (i) Side view. (ii) Top view. (d) Schematic model of Neu3, highlighting in black sticks some residues from the active site. The C-terminus is indicated. Cysteins are labelled in pink and a hypothetical fatty acid is drawn attached to one of them.
