ROLE OF THE N-TERMINUS IN THE STRUCTURE AND STABILITY OF CHICKEN ANNEXIN-V

The role of the short N-terminal region of chicken annexin V in the ma intenance of the protein structure and its influence in the conformati on of the calcium binding regions was analyzed. The N-terminal domain is not essential for protein folding, wild-type and dnt-annexin V show ing almost identical secondary structures. However, the partial trunca tion of the N-terminus significantly decreases the melting temperature of the protein and induces the partial exposure of Trp(187) which is normally located in a hydrophobic pocket of the calcium binding region of domain 3 of annexin V in the Ca2+-free form. (C) 1997 Federation o f European Biochemical Societies.