Figure 5

3D structural model of the N-terminal domain of Tic62 from Arabidopsis thaliana. The model was built by homology modelling using the 1XQ6 structure as a template. (a) Sequence alignment of the N-terminal domain of the atTic62 (residues 78–331) protein and the template. The predicted and known secondary structure of atTic62 and the template (1XQ6) are shown. Purple represents α-helix and yellow denotes β-strand. Residues involve in NADP-binding are underlined. The conserved aspartic acid residue required for stabilization of the adenine-binding pocket is found at the end of β3. For residues shade in orange see below; (b) Proposed structural model for atTic62 (cyan) superimposed onto the template (green). NADP ligand is shown in red. Slight differences are expected among subfamilies (e.g., absence of β5 and β6 in Tic62); (c) The hydrophobic region in Tic62 that might attach the protein to the membrane/Tic complex (residues 180–184 and 217–233 in atTic62) is shown in orange.