The Crystal Structure and Ion Channel Activity of Human Annexin II, a Peripheral Membrane Protein

• Published in: Journal of molecular biology 1996-04, Vol.257 (4), p.839-847
• Main Authors: Burger, Alex, Berendes, Robert, Liemann, Susanne, Benz, Jörg, Hofmann, Andreas, Göttig, Peter, Huber, Robert, Gerke, Volker, Thiel, Carsten, Römisch, Jürgen, Weber, Klaus
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; annexin; Annexin A2 - chemistry; Annexin A2 - genetics; Annexin A2 - metabolism; Binding Sites; Calcium - metabolism; crystal structure; Crystallography, X-Ray; Disulfides - chemistry; Electric Conductivity; exocytosis; Humans; ion channel activity; Ion Channels - chemistry; Ion Channels - genetics; Ion Channels - metabolism; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Models, Molecular; Molecular Sequence Data; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Protein Conformation; protein kinase substrate; Recombinant Proteins - metabolism; Sequence Homology, Amino Acid; Swine
• ISSN: 0022-2836; 1089-8638
• DOI: 10.1006/jmbi.1996.0205

Annexin II binds in a calcium-dependent manner to acidic phospholipids and is a substrate of some protein kinases. An N-terminally shortened form of human annexin II was crystallized and its molecular structure determined. It is very similar to two previously described members of this protein family, annexin I and annexin V. The protein structure is nearly completely α-helical organized as four compact domains which consist of five α-helices each. The domains surround a hydrophilic pore. The calcium binding sites are located at the convex side of the structure as in annexin V. Recombinant and natural porcine annexin II are active as ion channel with characteristics similar to annexin V, while N-terminally shortened annexin II and the heterotetramer (annexin II-p11) 2are inactive. Two cysteine residues, Cys133 and Cys262, form a disulphide bridge connecting domains II and III, adding further weight to the notion that ion channel activity does not require major structural rearrangements.