Figure 6 - full size

 

Figure 6.
Figure 6. Environment of the catalytic glutamate. (a) In TPRS, aGlu49 has two conformations, an extended active one interacting with the 3'-hydroxyl of IGP and an inactive one with the carboxylate hydrogen bonded with aTyr173. (b) In BX1 (yellow), Glu134 is positioned in the active conformation. Due to a number of substitutions, including Phe253<->aTyr173 and Ile207<->aLeu127, the corresponding inactive conformation seen in TPRS is not energetically favorable in the BX1 structure.

The above figure is reprinted by permission from Elsevier: J Mol Biol (2005, 352, 608-620) copyright 2005.