A POSSIBLE ROUTE FOR THE RELEASE OF FATTY-ACID FROM FATTY-ACID-BINDING PROTEIN

A simulation of the release of fatty acid from intestinal fatty acid-b inding protein was attempted, starting with the crystallographic model and using molecular-dynamic processes at different temperatures. The release of the ligand was observed only at high temperature, which per haps makes the process unreliable in detail. Nevertheless, the overall behaviour of the protein, also confirmed by the simulation performed at room temperature, strongly supports the idea that the fatty acid le aves the protein through an opening formed by alpha-helix II and turns beta C-beta D and beta E-beta F. Additionally, it suggests a role for the lack of hydrogen bonds between the main chains of beta-strands D and E: this feature, observed in all the protein structures of this fa mily which have currently been determined, seems to provide the struct ure with great flexibility, allowing the barrel to open and close with out disruption of the hydrogen-bond network.