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Evolutionary perspective on annexin calcium-binding domains
R O Morgan1, S Martin-Almedina, J M Iglesias
1Department of Biochemistry and Molecular Biology, Edificio Santiago Gascon, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain. romorgan@bioquimica.uniovi.es
Biochimica Et Biophysica Acta
|December 14, 2004
Summary
Molecular analysis reveals structural variations in annexin gene superfamilies, impacting calcium binding and ion channel function. These findings suggest complex mechanisms controlling annexin membrane interactions.
Area of Science:
- Molecular biology
- Evolutionary biology
- Biochemistry
Background:
- Annexins are calcium-dependent phospholipid-binding proteins crucial for membrane interactions and ion channel function.
- Structural variations in annexin calcium-binding domains can affect their biological activity.
Purpose of the Study:
- To investigate the evolutionary origin and structural variation of calcium-binding domains within the annexin gene superfamily.
- To understand the functional implications of these variations on membrane targeting and ion channel activity.
Main Methods:
- Molecular systematic analysis of the annexin gene superfamily.
- Identification and characterization of structural variations in calcium-binding domains.
- Comparative analysis of annexin sequences across different phyla.
Main Results:
- Approximately 36% of annexin repeat domains show loss of type two calcium-binding sites.
- A novel K/H/RGD motif was identified in 11% of annexin domains, conserved across phyla via convergent evolution.
- Specific annexin clades, including yeast and amphioxus, exhibit unique structural modifications impacting calcium-binding and channel regulation.
Conclusions:
- Selective erosion of calcium-binding sites and the presence of alternate ligands are common in annexins.
- These variations suggest a more complex regulatory mechanism for annexin membrane interaction and calcium channel operation than previously understood.