An evolutionary conserved motif is responsible for Immunoglobulin heavy chain packing in the B cell membrane(614 views) Varriale S, Merlino A, Coscia MR, Mazzarella L, Oreste U
Molecular Phylogenetics And Evolution (ISSN: 1055-7903), 2010 Dec; 57(3): 1238-1244.
Keywords: Immunoglobulin Evolution, Immunoglobulin Heavy Chain, Immunoglobulin Isotypes, Molecular Dynamics, Popc Lipid Bilayer, Purifying Selection, Transmembrane Helix, Amino Acid Sequence, Animal, Article, B Lymphocyte, Chemical Structure, Computer Simulation, Genetic Selection, Molecular Genetics, Nucleotide Sequence, Phylogeny, Protein Tertiary Structure, Sequence Analysis, Vertebrate, B-Lymphocytes, Conserved Sequence, Models, Molecular Sequence Data, Protein Structure, Chondrichthyes, Mammalia,
Affiliations: *** IBB - CNR ***
Institute of Protein Biochemistry, CNR, Via P. Castellino 111, 80131 Napoli, Italy
Department of Chemistry University of Naples 'Federico II', Via Cintia, 80126 Napoli, Italy
Institute of Biostructures and Bioimages, CNR, Via Mezzocannone 16, 80100 Napoli, Italy
References: Not available.
An evolutionary conserved motif is responsible for Immunoglobulin heavy chain packing in the B cell membrane
All species of vertebrates synthesize immunoglobulin molecules, which differ in an number of aspects but also share a few common features responsible for their function, such as the presence of a transmembrane domain in the membrane bound form of the immunoglobulin heavy chain (IgTMD) that ensures communication with the signal transducing Ig alpha-Ig beta peptides. We have analyzed the gene sequence encoding the IgTMD of different heavy chain isotypes of very distant species, from shark to mammals. The IgTMD sequences show a high degree of sequence identity and their encoding nucleotide sequences were shown to be subject to purifying selection at most sites. We have built molecular models of seven IgTMDs from different vertebrate species and have investigated the formation of homodimer in a palmitoyl oleoyl phosphatidylcholine (POPC) lipid bilayer by molecular dynamics simulations. We found that the conserved FXXXFXXS/TXXXS motif, never observed to date in protein transmembrane chains, is responsible for the two heavy chains association through two pairs of Phe-Phe hydrophobic interactions and two pairs of Ser/Thr-Ser/Ser hydrogen bonds. This interaction pattern, which stabilizes the dimer conformation in the lipid bilayer, was unique, being different from any other pattern identified in transmembrane helices to date. (C) 2010 Elsevier Inc. All rights reserved.
An evolutionary conserved motif is responsible for Immunoglobulin heavy chain packing in the B cell membrane