Premium
Determining calcium‐binding stoichiometry and cooperativity of parvalbumin and calmodulin by mass spectrometry
Author(s) -
Hu Peifeng,
Loo Joseph A.
Publication year - 1995
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1190300803
Subject(s) - chemistry , calmodulin , cooperativity , parvalbumin , electrospray ionization , calcium , mass spectrometry , cooperative binding , calcium binding protein , stoichiometry , molecule , binding site , metal , metal ions in aqueous solution , biophysics , crystallography , chromatography , biochemistry , organic chemistry , neuroscience , biology
The calcium‐binding properties of parvalbumin and calmodulin were investigated by electrospray ionization mass spectrometry (ESI‐MS). The two calcium sites of parvalbumin were found to be strongly cooperative in binding Ca 2+ ion. Up to four calcium ions were found to bind to calmodulin at high calcium concentration levels. Strong cooperativity was detected between the third and fourth Ca 2+ binding sites of calmodulin (ordered by loading sequence). Strong interactions were also indicated between the two halves of the calmodulin molecule. Demetallation of the gas‐phase ions can occur during the desolvation process, especially for ESI of aqueous solutions. However, the ESI‐MS methodology has the potential to provide insight into the intricate processes involved in metal site communications for other metalloproteins.