title: Binding States of Protein-Metal Complexes in Cells.
abstract: The identification of endogenous proteins as well as their binding to metal ions in living cells is determined by combining pulsed electrophoretic separations with nanoelectrospray ionization followed by mass spectrometric detection. This approach avoids problems resulting from the complicated cellular environment. In this manner, we demonstrate the rapid identification (300 ms or less) of intact proteins from living E. coli cells including the complexation of calmodulin with calcium ion. The latter showed different binding states from those observed in in vitro studies. These observations also reveal in vitro measurements do not necessarily represent the actual situation in living cells. We conclude that the attempted in situ measurement of intracellular proteins with minimal sampling processes should be preferred.
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Gongyu
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Siming
authors.initials: S
authors.lastname: Yuan
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei, Anhui 230029, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Yangzhong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Huang
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000737:chemistry*; D002147:Calmodulin / Q000032:analysis / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry* / Q000166:cytology*; D029968:Escherichia coli Proteins / Q000032:analysis* / Q000737:chemistry*; D007477:Ions / Q000737:chemistry
chemical_list: D002147:Calmodulin; D029968:Escherichia coli Proteins; D007477:Ions; D002118:Calcium