2rnd
Structure of the N-terminal BARpeptide in DPC micelles
Structural highlights
DiseaseBIN1_HUMAN Defects in BIN1 are the cause of centronuclear myopathy type 2 (CNM2) [MIM:255200. A congenital muscle disorder characterized by progressive muscular weakness and wasting involving mainly limb girdle, trunk, and neck muscles. It may also affect distal muscles. Weakness may be present during childhood or adolescence or may not become evident until the third decade of life. Ptosis is a frequent clinical feature. The most prominent histopathologic features include high frequency of centrally located nuclei in muscle fibers not secondary to regeneration, radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers.[1] FunctionBIN1_HUMAN May be involved in regulation of synaptic vesicle endocytosis. May act as a tumor suppressor and inhibits malignant cell transformation. Publication Abstract from PubMedBAR domains (Bin/Amphiphysin/Rvs-homology) generate and sense membrane curvature by binding the negatively charged membrane to their positively charged concave surfaces. N-BAR domains contain an N-terminal extension (helix-0) predicted to form an amphipathic helix upon membrane binding. We determined the NMR structure and nano-to-picosecond dynamics of helix-0 of the human Bin1/Amphiphysin II BAR domain in SDS and DPC micelles. Molecular dynamic simulations of this 34 amino acid peptide revealed electrostatic and hydrophobic interactions with the detergent molecules, which induce helical structure formation from residues 8-10 towards the C-terminus. The orientation in the micelles was experimentally confirmed by backbone amide proton exchange. Both simulation and experiment indicate that the N-terminal region is disordered, and the peptide curves to adopt the micelle shape. Deletion of helix-0 reduces tubulation of liposomes by the BAR domain, whereas the helix-0 peptide itself was fusogenic. These findings support models for membrane curving by BAR domains, where helix-0 increases the binding affinity to the membrane and enhances curvature generation. Structure and dynamics of Helix-0 of the N-BAR domain in Lipid Micelles and Bilayers.,Low C, Weininger U, Lee H, Schweimer K, Neundorf I, Beck-Sickinger AG, Pastor RW, Balbach J Biophys J. 2008 Jul 25. PMID:18658220[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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