title: Projection structure of a N-terminal deletion mutant of connexin 26 channel with decreased central pore density.
abstract: Gated gap junction channels are important cellular conduits for establishing and maintaining intercellular communication. The three-dimensional structure of a mutant human connexin 26 (Cx26M34A) by electron cryocrystallography revealed a plug-like density in the channel pore suggesting that physical blockage of the pore may be one mechanism of closure (Oshima et al. 2007, Proc Natl Acad Sci USA 104: 10034-10039). However, it remains to be determined what part of the sequence contributes to the plug. Here, we present the projection structure of an N-terminus deletion of Cx26M34A missing amino acids 2 to 7 (Cx26M34Adel2-7) crystallized in the same two-dimensional crystal form. A 10 A resolution projection map of Cx26M34Adel2-7 revealed that the plug density was dramatically reduced in comparison with that found in full-length Cx26 channel. The difference map between the deletion and full-length Cx26M34A channels strongly suggests that the N-terminus of connexin contributes to the plug for the physical closure of gap junction channels.
authors.affiliation: Department of Biophysics, Faculty of Science, Kyoto University, Kyoto, Japan.
authors.forename: Atsunori
authors.initials: A
authors.lastname: Oshima
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Tani
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hiroaki
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiyoshi
authors.forename: Gina E
authors.initials: GE
authors.lastname: Sosinsky
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D000072259:Connexin 26; D017630:Connexins / Q000737:chemistry* / Q000235:genetics* / Q000502:physiology; D017629:Gap Junctions / Q000737:chemistry / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D017384:Sequence Deletion; D018411:Spodoptera
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26