title: Crystal structure of SEDL and its implications for a genetic disease spondyloepiphyseal dysplasia tarda.
abstract: SEDL is an evolutionarily highly conserved protein in eukaryotic organisms. Deletions or point mutations in the SEDL gene are responsible for the genetic disease spondyloepiphyseal dysplasia tarda (SEDT), an X-linked skeletal disorder. SEDL has been identified as a component of the transport protein particle (TRAPP), critically involved in endoplasmic reticulum-to-Golgi vesicle transport. Herein, we report the 2.4 A resolution structure of SEDL, which reveals an unexpected similarity to the structures of the N-terminal regulatory domain of two SNAREs, Ykt6p and Sec22b, despite no sequence homology to these proteins. The similarity and the presence of unusually many solvent-exposed apolar residues of SEDL suggest that it serves regulatory and/or adaptor functions through multiple protein-protein interactions. Of the four known missense mutations responsible for SEDT, three mutations (S73L, F83S, V130D) map to the protein interior, where the mutations would disrupt the structure, and the fourth (D47Y) on a surface at which the mutation may abrogate functional interactions with a partner protein.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D008040:Genetic Linkage; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry; D026901:Membrane Transport Proteins; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D020125:Mutation, Missense; D010009:Osteochondrodysplasias / Q000235:genetics* / Q000378:metabolism*; D017354:Point Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D050683:R-SNARE Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014960:X Chromosome
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D050683:R-SNARE Proteins; C432415:Sec22b protein, mouse; C120759:TRAPPC2 protein, human; D014157:Transcription Factors; C491482:YKT6 protein, human