Avtor/Urednik		Grubič, Z; Štalc, A; Šentjurc, M; Pečar, S; Gentry, MK; Doctor, BP
Naslov		Different effects of two peripheral anionic site-binding ligands on acetylcholinesterase active-site gorge topography revealed by electron paramagnetic resonance
Tip		članek
Vir		Biochim Biophys Acta
Vol. in št.		Letnik 1249
Leto izdaje		1995
Obseg		str. 155-60
Jezik		eng
Abstrakt		Both propidium and monoclonal antibody (mAb) 25B1 bind to the peripheral anionic site region of fetal bovine serum acetylcholinesterase (FBS AChE). Using electron paramagnetic resonance (EPR) with spin-labelled organophosphate specifically bound to the AChE active-site serine, we studied the effects of both ligands on the topography of the AChE active-site gorge. After incubation of FBS AChE with Fab fragments of mAb 25B1, freedom of motion of our spin label became more restricted, suggesting closing of the gorge. Stabilization against heat denaturation was also observed. No alterations in the freedom of motion or protection against heat denaturation could be detected after propidium binding. Our results demonstrate that two ligands binding to the peripheral anionic site region of AChE have different effects, suggesting a complex structure for this region of the molecule that allows various type of interactions with different ligands. We also demonstrate that EPR is a suitable tool for studying microtopographical alterations at the active sites of cholinesterases.
Deskriptorji		ACETYLCHOLINESTERASE BINDING SITES PROPIDIUM ANTIBODIES, MONOCLONAL ELECTRON SPIN RESONANCE SPECTROSCOPY