title: Annexin A2/P11 interaction: new insights into annexin A2 tetramer structure by chemical crosslinking, high-resolution mass spectrometry, and computational modeling.
abstract: During the past few years, the structural analysis of proteins and protein complexes by chemical crosslinking and mass spectrometry has enjoyed increasing popularity. With this approach we have investigated the quaternary structure of the complex between annexin A2 and p11, which is involved in numerous cellular processes. Although high-resolution data are available for both interaction partners as well as for the complex between two p11 subunits and two annexin A2 N-terminal peptides, the structure of the complete annexin A2/p11 heterotetramer has not yet been solved at high resolution. Thus, the quaternary structure of the biologically relevant, membrane-bound annexin A2/p11 complex is still under discussion, while the existence of a heterotetramer or a heterooctamer is the prevailing opinion. We gained further insight into the spatial organization of the annexin A2/p11 heterotetramer by employing chemical crosslinking combined with high-resolution mass spectrometry. Furthermore, tandem mass spectrometry served as a tool for an exact localization of crosslinked amino acid residues and for a confirmation of crosslinked product assignment. On the basis of distance constraints from the crosslinking data we derived structural models of the annexin A2/p11 heterotetramer by computational docking with Rosetta. We propose an octameric model for the annexin A2/p11 complex, which exerts annexin A2 function. The proposed structure of the annexin A2/p11 octamer differs from so far suggested models and sheds new light into annexin A2/p11 interaction.
authors.affiliation: Biotechnological-Biomedical Center, Faculty of Chemistry and Mineralogy, University of Leipzig, D-04103 Leipzig, Germany.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Schulz
authors.forename: Stefan
authors.initials: S
authors.lastname: Kalkhof
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmidt
authors.forename: Christian
authors.initials: C
authors.lastname: Ihling
authors.forename: Christoph
authors.initials: C
authors.lastname: Stingl
authors.forename: Karl
authors.initials: K
authors.lastname: Mechtler
authors.forename: Olaf
authors.initials: O
authors.lastname: Zschörnig
authors.forename: Andrea
authors.initials: A
authors.lastname: Sinz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017306:Annexin A2 / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D003198:Computer Simulation; D003432:Cross-Linking Reagents; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D009418:S100 Proteins / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D034421:Sus scrofa; D053719:Tandem Mass Spectrometry; D000099248:S100 Calcium Binding Protein A10
chemical_list: D017306:Annexin A2; D002118:Calcium; D003432:Cross-Linking Reagents; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10