Annexin A5 D226K structure and dynamics: identification of a molecular switch for the large-scale conformational change of domain III

• Published in: FEBS letters 2001-03, Vol.493 (2), p.122-128
• Main Authors: Sopkova-De Oliveira Santos, Jana, Vincent, Michel, Tabaries, Sébastien, Chevalier, Anne, Kerbœuf, Daniel, Russo-Marie, Françoise, Lewit-Bentley, Anita, Gallay, Jacques
• Format: Article
• Language: English
• Subjects: Annexin 5; Annexin A5 - chemistry; Annexin A5 - genetics; Anx5, annexin A5; Calcium - pharmacology; Calcium- and pH-induced conformational change; Computer Simulation; Crystallography, X-Ray; D226, aspartic acid 226; D226K, mutant of human annexin V where aspartic 226 is replaced by a lysine; DNA Primers - genetics; Electrostatic interaction; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; MEM, maximum entropy method; Models, Molecular; Point Mutation; Protein Conformation - drug effects; Protein Structure, Tertiary; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Static Electricity; T224, threonine 224; T224V, mutant of human annexin V where threonine 224 is replaced by a valine; Thermodynamics; Time-resolved fluorescence; Tryptophan; W187, tryptophan 187; X-ray diffraction
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(01)02285-2

The domain III of annexin 5 undergoes a Ca 2+- and a pH-dependent conformational transition of large amplitude. Modeling of the transition pathway by computer simulations suggested that the interactions between D226 and T229 in the IIID–IIIE loop on the one hand and the H-bond interactions between W187 and T224 on the other hand, are important in this process [Sopkova et al. (2000) Biochemistry 39, 14065–14074]. In agreement with the modeling, we demonstrate in this work that the D226K mutation behaves as a molecular switch of the pH- and Ca 2+-mediated conformational transition. In contrast, the hydrogen bonds between W187 and T224 seem marginal.