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![[Figure 7]](kw5140fig7mag.jpg)
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Figure 7
The top panels show close-ups of the two distinct interfaces formed in Fol modules with a β8α8 and a β8α7 fold in cartoon mode. Important residues that form part of the interfaces are shown as sticks. The bottom panels display the graphical sequence variance between the C-terminal regions in the classical (β8α8) and `twist' (β8α7) folds, as generated with WebLogo (Crooks et al., 2004  ). More than 300 sequences (with representative sequences exhibiting between 90 and 15% sequence identity) for each of the different folds were used in WebLogo. The numbering at the bottom corresponds to the T. maritima (left) and T. thermophilus (right) sequences, whereas the numbering at the top is used as a reference and corresponds to the positions upstream (negative) or downstream (positive) of the last residue in the β8 strand. In (a) helix α8 (green) is involved in intermolecular interactions with helices α7 and α1 (green) and mainly hydrophobic intramolecular interactions with helices α7′ and α8′ (red) from an adjacent monomer. In (b) helix α8cF (teal) forms extensive intramolecular hydrophobic interactions with helices α8dF (teal) and α7 (green). The solvent-exposed polar residues Asp592, Glu593 and Lys596 of helix α7 [positions −12, −11 and −8; bottom panel in (b)] in T. thermophilus MS are replaced by the hydrophobic residues Val525, Leu526 and Ser529 [positions −12, −11 and −8; bottom panel in (a)] that form part of the intramolecular interface in T. maritima MS. The solvent-exposed Pro611, Gln614 and Glu617 residues [positions 7, 10 and 13; bottom panel in (b)] in T. thermophilus MS are replaced by the hydrophobic residues Leu544, Thr547 and Leu552 [positions 7, 10 and 13; bottom panel in (a)] that reside in helix α8 and form part of its intermolecular interface with α7 and α1 in T. maritima MS. In T. thermophilus MS, the hydrophobic residues Ala623 and Leu626 residing in α8cF [positions 19 and 22; bottom panel in (b)] are replaced by the charged residues Glu556 and Glu559 in T. maritima MS. |
![[Figure 7]](kw5140fig7.jpg)
 | STRUCTURAL BIOLOGY |
ISSN: 2059-7983
