Avtor/Urednik		Vardjan, Nina
Naslov		Študij molekularnega mehanizma presinaptično nevrotoksičnega delovanja amoditoksinov
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		2003
Obseg		str. 118
Jezik		slo
Abstrakt		Ammodytoxins (Atx) are presynaptically acting neurotoxic secretory phospholipases AZ (sPLA2) of type IIA from the venom of the long-nosed viper (Vipera ammodytes ammodytes). They block the release of acetylcholine from the axon terminals of motor neurons, causing muscle paralysis. The molecular mechanism underlying the presynaptic neurotoxicity of Atx and the related presynaptically neurotoxic sPLA2 is still unclear. It has been proposed that sPLA2 neurotoxicity is dependent on its enzymatic activity and binding to specific receptors in or on axon terminals of motor neurons. Studying the presynaptically neurotoxic action of Atx two high molecular mass receptors for Atx were identified in porcine tissues, one in porcine liver, L200, and the other in porcine brain, R180. We purified L200 in an active form. Using tandem mass spectrometry, both porcine high-molecular mass receptors were identified as members of the group of M-type sPLA2 receptors (sPLAZRs). Since we found only one gene for M-type sPLA2R in the porcine genome, it is likely that porcine M-type sPLA2Rs, which differ in molecular mass by approx.20 kDa, are modified differently, either post-translationally or post-transcriptionally. Deglycosylation studies on R180 and L200 showed that the majority of the differences in molecular mass . between the receptors are the consequence of different N-glycosylation of the receptors. However, some additional structural differences between the receptors must exist, since porcine M-type sPLAzRs still differ in molecular mass by approx. 5 kDa after N-deglycosylation. This difference could be the consequence of an additional post-translational modification of the receptors (D-glycosylation) or a post-transcriptional modification of their mRNA (alternative splicing). (Abstract truncated at 2000 characters).
Deskriptorji		VIPER VENOMS PHOSPHOLIPASES A RECEPTORS, PRESYNAPTIC BINDING SITES AXONS RECOMBINANT PROTEINS HEPARIN CARRIER PROTEINS PLASMIDS MICE SWINE RABBITS LIVER CEREBRAL CORTEX CLONING, MOLECULAR TRANSFORMATION, GENETIC DNA FRAGMENTATION BASE SEQUENCE AMINO ACID SEQUENCE