Mastoparan binding induces Ca(2+)-transfer between two globular domains of calmodulin: a 1H NMR study.
The interaction between calmodulin and mastoparan at various concentrations of calcium ions was studied by 1H NMR. It was found that at lower mastoparan concentrations 1 mol of mastoparan binds to both the C-terminal-half and N-terminal-half regions of calcium-saturated calmodulin. The mastoparan affinity is much greater for the C-terminal-half region than for the N-terminal-half region. At higher mastoparan concentrations, a further 1 mol of mastoparan binds to the N-terminal-region of calcium saturated calmodulin. The results can be interpreted in terms of the assumption that the N-terminal-half region of calmodulin with mastoparan has a higher calcium ion affinity than the C-terminal-half region without mastoparan. It is suggested that calcium ions transfer from the C-terminal-half region of calmodulin without mastoparan to the N-terminal-half region of calmodulin with mastoparan. This calcium ion transfer is discussed from the viewpoint of enzyme activation by calmodulin.
Ohki
S Y
SY
Department of Polymer Science, Faculty of Science, Hokkaido University.
Yazawa
M
M
Yagi
K
K
Hikichi
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry; D001692:Biological Transport; D002118:Calcium / Q000737:chemistry*; D002147:Calmodulin / Q000737:chemistry*; D036341:Intercellular Signaling Peptides and Proteins; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008969:Molecular Sequence Data; D008974:Mollusca; D010455:Peptides; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D014862:Wasp Venoms / Q000737:chemistry*
D001059:Apoproteins; D002147:Calmodulin; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014862:Wasp Venoms; C037500:mastoparan; D002118:Calcium