Al(3+) interaction sites of calmodulin and the Al(3+) effect on target binding of calmodulin.
The interaction between calmodulin (CaM) and Al(3+) was studied by spectroscopic methods. Heteronuclear two-dimensional NMR data indicated that peaks related to the both lobes and middle of the central helix of CaM are largely affected by Al(3+). But chemical shift perturbation suggested that overall conformation of Ca(2+)-loaded CaM is not changed by Al(3+) binding. It is thought that Al(3+) interaction to the middle of the central helix is a key for the property of CaM's target recognition. If the structure and/or flexibility of the central helix are/is changed by Al(3+), target affinity to CaM must be influenced by Al(3+). Thus, we performed surface plasmon resonance experiments to observe the effect of Al(3+) on the target recognition by CaM. The data clearly indicated that target affinity to CaM is reduced by addition of Al(3+). All the results presented here support a hypothesis that Al(3+) may affect on the Ca(2+) signaling pathway in cells.
Kurita
Hiroyuki
H
Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Tatsunokuchi, Ishikawa 923-1292, Japan.
Nakatomi
Akiko
A
Shimahara
Hideto
H
Yazawa
Michio
M
Ohki
Shin-Ya
SY
D000535:Aluminum / Q000032:analysis / Q000737:chemistry*; D001665:Binding Sites; D002147:Calmodulin / Q000032:analysis / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding
D002147:Calmodulin; D000535:Aluminum