All species of vertebrates synthesize immunoglobulin molecules, which differ in a 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 communica¬tion with the signal transducing 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 identified in transmembrane helices to date.

Immunoglobulin heavy chain transmembrane domains packing in lipid bilayer / M. R., Coscia; S., Varriale; Merlino, Antonello; L., Mazzarella; U., Oreste. - ELETTRONICO. - (2011), pp. P94-P94. (Intervento presentato al convegno Recent advances in membrane biochemistry tenutosi a Cambridge nel 5-7 Gennaio 2011).

Immunoglobulin heavy chain transmembrane domains packing in lipid bilayer

MERLINO, ANTONELLO;
2011

Abstract

All species of vertebrates synthesize immunoglobulin molecules, which differ in a 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 communica¬tion with the signal transducing 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 identified in transmembrane helices to date.
2011
Immunoglobulin heavy chain transmembrane domains packing in lipid bilayer / M. R., Coscia; S., Varriale; Merlino, Antonello; L., Mazzarella; U., Oreste. - ELETTRONICO. - (2011), pp. P94-P94. (Intervento presentato al convegno Recent advances in membrane biochemistry tenutosi a Cambridge nel 5-7 Gennaio 2011).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/451559
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