title: Guanidination of notexin alters its membrane-damaging activity in response to sphingomyelin and cholesterol.
abstract: To elucidate the contribution of phospholipase A 2 (PLA2) activity of notexin to its ability to perturb membranes, comparative studies on the interaction of notexin and guanidinated notexin (Gu-notexin) with egg yolk phosphatidylcholine (EYPC), EYPC/egg yolk sphingomyelin (EYSM) and EYPC/EYSM/cholesterol vesicles were conducted. EYSM notably reduced the membrane-damaging activity of notexin against EYPC vesicles, but had an insignificant influence on that of Gu-notexin. Unlike the effects noted with notexin, inactivation of PLA 2 activity by EDTA led to a reduction in the ability of Gu-notexin to induce EYPC/EYSM vesicle leakage and to increase Gu-notexin-induced membrane permeability of EYPC/EYSM/cholesterol vesicles. The geometrical arrangement of notexin and Gu-notexin in contact with either EYPC/EYSM vesicles or EYPC/EYSM/cholesterol vesicles differed. Moreover, global conformation of notexin and Gu-notexin differed in either Ca2+-bound or metal-free states. These results indicate that notexin and Gu-notexin could induce membrane permeability without the involvement of PLA 2 activity, and suggest that guanidination alters the membrane-bound mode of notexin on damaging phospholipid vesicles containing sphingomyelin and cholesterol.
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
authors.forename: Pei-Hsiu
authors.initials: PH
authors.lastname: Kao
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Chiou
authors.forename: Shinne-Ren
authors.initials: SR
authors.lastname: Lin
authors.forename: Long-Sen
authors.initials: LS
authors.lastname: Chang
mesh_terms: D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000737:chemistry*; D004530:Egg Yolk / Q000737:chemistry; D004546:Elapid Venoms / Q000737:chemistry*; D057075:Enzyme Assays; D005452:Fluoresceins / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D009498:Neurotoxins / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000737:chemistry; D054467:Phospholipases A2 / Q000737:chemistry*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013109:Sphingomyelins / Q000737:chemistry*
chemical_list: D004546:Elapid Venoms; D005452:Fluoresceins; D008081:Liposomes; D009498:Neurotoxins; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D013109:Sphingomyelins; C005082:notexin; C483858:phosphatidylethanolamine; D002784:Cholesterol; D054467:Phospholipases A2; D019791:Guanidine; C007740:fluorexon