Structural characterization of synaptic vesicles and the synaptic vesicle protein synaptogyrin ( p29), a member of a novel protein family.

摘要

Quantitative and qualitative analyses regarding the composition and dimensions of a typical synaptic vesicle were performed in order to provide a structural framework for constructing a molecular model of the synaptic vesicle as a model trafficking organelle. Biophysical characteristics of synaptic vesicles such as hydrodynamic radius and density were determined using the methods of dynamic laser scattering and density gradient centrifugation. Protein and phospholipid assays were employed in conjunction with electron microscopy to estimate the protein and lipid content of a single synaptic vesicle. The identity and composition of the membrane proteins of synaptic vesicles were explored using a modified two-dimensional gel electrophoresis method optimal for the separation of membrane proteins. This method allowed us to isolate and structurally characterize a previously identified synaptic vesicle protein called p29, now renamed synaptogyrin.;Synaptogyrin is a synaptic vesicle protein which is uniformly distributed in the nervous system (Baumert et al., 1990). We have cloned and sequenced the cDNA encoding synaptogyrin, and the sequence predicts a protein of M