 These conformational changes also result in the formation of a 20 Å long ammonia channel, one of the most striking features of this enzyme.This channel lacks any hydrogen bonding sites, to ensure easy diffusion of ammonia from one active site to the other.This channel ensures ammonia released from glutamine reaches the PRTase catalytic site, and it differs from the channel in CPSase in that it is hydrophobic rather than polar, and transient rather than permanent.