Figure 3: A BT-like domain in the structure of two-subunit PC.
From: A distinct holoenzyme organization for two-subunit pyruvate carboxylase
(a) Schematic drawing of the BT-like domain in MfPC. The helix comes from the α subunit (red), and the two four-stranded β-sheets come from two separate β subunits (green and yellow). Each subunit is given a different colour to highlight the origins of the protein segments in the BT-like domain. (b) Overlay of the structures of the BT-like domain of MfPC (orange) and the BT domain of PCC (grey)20. (c) Sequence alignment of the residues in the α helix of the PT domain in single-chain PCs. Hydrophobic residues are coloured purple, and hydrophilic ones in cyan. (d) The α helix of the PT domain in SaPC is amphipathic, with half of its surface having hydrophilic residues and exposed to the solvent. Hydrophobic side chains are coloured in purple, and hydrophilic ones in cyan. (e) Sequence alignment of the residues in the α helix of the BT-like domain in two-subunit PCs, at the C-terminal end of the α subunit. (f) The α helix of the BT-like domain in MfPC is hydrophobic, completely surrounded by the β-barrel and having mostly small side chains.
