4bon

The structure and super-organization of acetylcholine receptor-rapsyn complexes class BThe structure and super-organization of acetylcholine receptor-rapsyn complexes class B

4bon, resolution 40.00Å Show:Asymmetric Unit Biological Assembly Structural highlights 4bon is a 5 chain structure with sequence from Torpedo marmorata. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 4bog, 4boi, 4boo Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ACHA_TORMA] After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Publication Abstract from PubMed The scaffolding protein at the neuromuscular junction, rapsyn, enables clustering of nicotinic acetylcholine receptors in high concentration and is critical for muscle function. Patients with insufficient receptor clustering suffer from muscle weakness. However, the detailed organization of the receptor-rapsyn network is poorly understood: it is unclear whether rapsyn first forms a wide meshwork to which receptors can subsequently dock or whether it only forms short bridges linking receptors together to make a large cluster. Furthermore, the number of rapsyn-binding sites per receptor (a heteropentamer) has been controversial. Here, we show by cryoelectron tomography and subtomogram averaging of Torpedo postsynaptic membrane that receptors are connected by up to three rapsyn bridges, the minimum number required to form a 2D network. Half of the receptors belong to rapsyn-connected groups comprising between two and fourteen receptors. Our results provide a structural basis for explaining the stability and low diffusion of receptors within clusters. Structure and superorganization of acetylcholine receptor-rapsyn complexes.,Zuber B, Unwin N Proc Natl Acad Sci U S A. 2013 Jun 10. PMID:23754381 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nicotinic Acetylcholine Receptor