Table 2. The width of the catalytic cleft in various structures of Trpase.

Trpase structure	Distance between C atoms of Lys127 and Ala373 (or equivalent) ()
Holo E. coli (PDB entry 4w4h): open cleft	34
Holo P. vulgaris (PDB entry 1ax4): open cleft	34
Holo subunit of the ‘semi-holo’ (PDB entry 4w1y chain A): open cleft	35
Apo I (Ku et al., 2006 ▶; PDB entry 2c44): closed cleft	29
Apo II (Tsesin et al., 2007 ▶; PDB entry 2oqx): wide-open cleft	38
Apo subunit of the ‘semi-holo’ (PDB entry 4w1y chain B): wide-open cleft	37