J. Biol. Chem., Vol. 266, Issue 14, 9023-9031, May, 1991
Purification of a protein histidine kinase from the yeast Saccharomyces cerevisiae. The first member of this class of protein kinases
JM Huang, YF Wei, YH Kim, L Osterberg and HR Matthews
Department of Biological Chemistry, University of California, Davis 95616.
An enzyme of molecular weight 32,000 comprising a single subunit has been
isolated from whole cell extracts of the yeast Saccharomyces cerevisiae. In
vitro, the enzyme transfers the gamma phosphate of ATP to a protein
substrate, histone H4, to produce an alkali-stable phosphorylation.
Modification of the substrate histidine with diethylpyrocarbonate prevented
phosphorylation. Phosphoamino acid analysis of the phosphorylated substrate
showed the presence of 1- phosphohistidine. Hence, the isolated enzyme is a
protein histidine kinase. A novel assay for acid-labile alkali-stable
protein phosphorylation was used in the purification of the kinase activity
to a final specific activity of 2,700 nmol/15 min/mg. The purified enzyme
phosphorylates specifically histidine 75 in histone H4 and does not
phosphorylate histidine 18 nor histidine residues in any other core
histone. Steady state kinetic data are consistent with an ordered
sequential reaction with Km values for Mg-ATP and histone H4 of 60 and 17
microM, respectively. The protein histidine kinase requires a divalent
cation such as Mg2+, Co2+, or Mn2+ but will not use Ca2+, Zn2+, Cu2+, Fe2+,
spermine, or spermidine. This is the first purification of an enzyme that
catalyzes N-linked phosphorylation in proteins.