Figure 6

Two TIM barrel domains with low Z-scores. (a) D1gqia1 with Z-score of 3.03, which is the lowest among all Z-score of TIM barrel domains in the ASTRAL40 dataset. The domain has 561 residues, of which only the N-terminal 320 residues, colored in different shades of blue to green, may be considered to constitute the symmetric core. The remaining 241-residue C-terminal extension, colored white, is not symmetric. (b) D1jfxa_ with the Z-score of 7.20, which is near the lower cutoff value of 8, in rainbow color from blue for the N-terminus to red for the C-terminus. This structure has a distorted TIM barrel fold: the fifth helix (yellow) is extended and barely discernible, 6^th, 7^th, and 8^th helices are missing and the 8^th strand is in reverse direction, being anti-parallel to its neighboring 7^th and 1^st strands.