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Updated: Aug 11, 2026

Quantification of Bacterial Histidine Kinase Autophosphorylation Using a Nitrocellulose Binding Assay
Published on: January 11, 2017
Phosphohistidyl active sites in polyphosphate kinase of Escherichia coli
K D Kumble1, K Ahn, A Kornberg
1Department of Biochemistry, Beckman Center, Stanford University School of Medicine, CA 94305-5307, USA.
Abstract:
In the synthesis of inorganic polyphosphate (polyP) from ATP by polyphosphate kinase (PPK; EC 2.7.4.1) of Escherichia coli, an N-P-linked phosphoenzyme was previously identified as the intermediate. The phosphate is presumed to be linked to N3 of the histidine residue because of its chemical stabilities and its resemblance to other enzymes known to contain N3-phosphohistidine. Tryptic digests of [32P]PPK contain a predominant 32P-labeled peptide that includes His-441. Of the 16 histidine residues in PPK of E. coli, 4 are conserved among several bacterial species. Mutagenesis of these 4 histidines shows that two (His-430 and His-598) are unaffected in function when mutated to glutamine, whereas two others (His-441 and His-460) mutated to glutamine or alanine fail to be phosphorylated, show no enzymatic activities, and fail to support polyP accumulation in cells bearing these mutant enzymes.
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