2yv9 | pdb_00002yv9
Crystal structure of the CLIC homologue EXC-4 from c. elegans
Structural highlights
Function[EXC4_CAEEL] May insert into membranes and form chloride ion channels. Involved in the formation of the excretory canal. Required to prevent cystic lumenal expansions in the excretory cell. Not required for formation of the initial tube, but is required for regulating the size of the tube lumen as it grows.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structures of two CLIC family members DmCLIC and EXC-4 from the invertebrates Drosophila melanogaster and Caenorhabditis elegans, respectively, have been determined. The proteins adopt a glutathione S-transferase (GST) fold. The structures are highly homologous to each other and more closely related to the known structures of the human CLIC1 and CLIC4 than to GSTs. The invertebrate CLICs show several unique features including an elongated C-terminal extension and a divalent metal binding site. The latter appears to alter the ancestral glutathione binding site, and thus, the invertebrate CLICs are unlikely to bind glutathione in the same manner as the GST proteins. Purified recombinant DmCLIC and EXC-4 both bind to lipid bilayers and can form ion channels in artificial lipid bilayers, albeit at low pH. EXC-4 differs from other CLIC proteins in that the conserved redox-active cysteine at the N-terminus of helix 1 is replaced by an aspartic acid residue. Other key distinguishing features of EXC-4 include the fact that it binds to artificial bilayers at neutral pH and this binding is not sensitive to oxidation. These differences with other CLIC family members are likely to be due to the substitution of the conserved cysteine by aspartic acid. Proteins 2008. (c) 2007 Wiley-Liss, Inc. Comparison of vertebrate and invertebrate CLIC proteins: The crystal structures of Caenorhabditis elegans EXC-4 and Drosophila melanogaster DmCLIC.,Littler DR, Harrop SJ, Brown LJ, Pankhurst GJ, Mynott AV, Luciani P, Mandyam RA, Mazzanti M, Tanda S, Berryman MA, Breit SN, Curmi PM Proteins. 2007 Oct 23;71(1):364-378. PMID:17985355[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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