Identification and characterization of zinc binding sites in protein kinase C.
Metal ion coordination in the regulatory domain of protein kinase C (PKC) is suggested by the conservation of six cysteines and two histidines in two homologous regions found therein. By monitoring x-ray fluorescence from a purified sample of rat PKC beta I overexpressed in insect cells, direct evidence has been obtained that PKC beta I tightly binds four zinc ions (Zn2+) per molecule. Extended x-ray absorption fine structure (EXAFS) data are best fit by an average Zn2+ coordination of one nitrogen and three sulfur atoms. Of the plausible Zn2+ coordination models, only those featuring nonbridged Zn2+ sites accommodate the EXAFS data and all of the conserved potential ligands.
Hubbard
S R
SR
Howard Hughes Medical Institute, New York, NY.
Bishop
W R
WR
Kirschmeier
P
P
George
S J
SJ
Cramer
S P
SP
Hendrickson
W A
WA
D015502:Absorptiometry, Photon / Q000379:methods; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011493:Protein Kinase C / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015032:Zinc / Q000378:metabolism*
D046911:Macromolecular Substances; D011994:Recombinant Proteins; D011493:Protein Kinase C; D015032:Zinc