Purification of a Bovine Liver Protein Rapidly Phosphorylated by Adenosine Triphosphate

Histidine phosphorylation in histones and in other mammalian proteins

The investigation of protein histidine phosphorylation has required the development of a number of methods that differ from traditional methods of phosphoprotein analysis that were developed to study phosphorylation of serine, threonine, and tyrosine, which are, unlike phosphohistidine, acid-stable. The investigation of histidine phosphorylation is further complicated by the fact that in mammalian proteins, phosphorylation appears to occur at either 1-N or 3-N positions of the imidazole ring, depending on the source of the kinase. In this review, we describe methods developed for phosphoamino acid analysis to detect phosphohistidine, including the determination of the isoform present, using chromatographic and mass spectrometric analysis of phosphoprotein hydrolysates and 1H- and 31P NMR analysis of intact phosphoproteins and phosphopeptides. We also describe methods for the assay of protein histidine kinase activity, including a quantitative assay of alkali-stable, acid-labile protein phosphorylation, and an in-gel kinase assay applied to histidine kinases. Most of the detailed descriptions of methods are as they are applied in our laboratory to the investigation of histone H4 phosphorylation and histone H4 histidine kinases, but which can be applied to the phosphorylation of any proteins and to any such histidine kinases.

cvhA gene of Streptomyces hygroscopicus 10-22 encodes a negative regulator for mycelia development

A five-gene cluster cvhABCDE was identified from Streptomyces hygroscopicus 10-22. As the first gene of this cluster, cvhA encoded a putative sensor histidine kinase with a predicted sensor domain consisting of two trans-membrane segments at the N-terminus and a conserved HATPase_c domain at the C-terminus. The C-terminus polypeptide of CvhA expressed in Escherichia coli was purified and shown to be autophosphorylated with [gamma-32P]ATP in vitro. The phosphoryl group was acid-labile and basic-stable, which supported histidine as the phosphorylation residue. No obvious difference of mycelia development was observed between the null mutant of cvhA generated by targeted gene replacement and the wild-type parental strain 10-22 grown on solid soya flour medium with 2%-8% glucose or sucrose, but the cvhA mutant could form much more abundant aerial mycelia and spores than the wild-type strain on solid soya flour medium supplemented with 6%-8% mannitol, 6%-8% sorbitol, 4%-6% mannose, or 4%-6% fructose. This phenotype was complemented by the cloned wild-type cvhA gene, and no difference was observed for growth curves of the cvhA mutant and the wild strain in liquid minimal medium with the tested sugars at a concentration of 4%, 6% and 8%. We thus propose that CvhA is likely a sensor histidine kinase and negatively regulates the morphological differentiation in a sugar-dependent manner in S. hygroscopicus 10-22.

The histidine protein kinase superfamily

Signal transduction in microorganisms and plants is often mediated by His-Asp phosphorelay systems. Two conserved families of proteins are centrally involved: histidine protein kinases and phospho-aspartyl response regulators. The kinases generally function in association with sensory elements that regulate their activities in response to environmental signals. A sequence analysis with 348 histidine kinase domains reveals that this family consists of distinct subgroups. A comparative sequence analysis with 298 available receiver domain sequences of cognate response regulators demonstrates a significant correlation between kinase and regulator subfamilies. These findings suggest that different subclasses of His-Asp phosphorelay systems have evolved independently of one another.

Prevalence of nucleoside diphosphate kinase autophosphorylation in human colon carcinoma versus normal colon homogenates

The G-regulatory proteins of adenylate cyclase, tubulin, and the ras oncogene protein product require the production of GTP from ATP in order to exert their effects within the cell. This implies that the activity of nucleoside diphosphate kinase (NDPK) plays a major role in the regulation of cellular events requiring GTP and that the level of activity of this enzyme is critical. This report presents a simple method for trapping a specific isozyme of NDPK in its high-energy phosphorylated form (NDPK approximately P) using EDTA and demonstrates that this NDPK approximately P is tenfold higher in malignant colon tumor tissue than in normal colon tissue. This autophosphorylation of the 21,000 and 24,000 Mr subunits of NDPK occurs rapidly at 0 degrees C, will use either [gamma-32P]ATP, [gamma-32P]GTP, or the corresponding 8-azidopurine photoprobes, is intramolecular, displays saturation effects, and is prevented from forming if GTP gamma S is added. Dephosphorylation in the homogenate occurs rapidly upon addition of Mg2+ or any nucleoside-5'-diphosphate. The subunits autophosphorylated in the homogenates are mostly in the soluble phase, and they comigrate with the subunits of pure NDPK from human erythrocytes. Cross-addition of normal and malignant homogenates does not decrease the level of autophosphorylation of NDPK, which indicates that the level of NDPK approximately P may be a quantitative measure of the level of this specific NDPK isozyme form. Assays for NDPK activity show correspondingly elevated levels in the malignant homogenates. Using western blot and photoaffinity labeling techniques, we distinguished the NDPK approximately P subunits from two closely migrating GTP-binding proteins. These were identified as the ras gene protein product and a 20,000 Mr protein, which comigrates identically with ADP-ribosylating factor (ARF). The ARF also comigrates in a tight band that is phosphorylated by [gamma 32P]ATP or [gamma-32P]GTP when Mg2+ is present.

Effect of chemical modification of a histidine and a lysine residue of pea seed nucleoside diphosphate kinase

Chemical modification of a histidine and lysine residue inactivates pea seed nucleoside diphosphate kinase (NDP kinase). Thus there seems to be a reactive lysine residue, at the active site of pea seed NDP kinase, in addition to the histidine residue phosphorylated by the substrate ATP as a consequence of the enzyme reaction. The presence of a reactive lysine at the active site of the enzyme could explain why a small amount of N-epsilon-phospholysine, as well as 1-phosphohistidine and 3-phosphohistidine, is formed on alkaline hydrolysis of the enzyme.

Nucleophile in the active site of Escherichia coli galactose-1-phosphate uridylyltransferase: degradation of the uridylyl-enzyme intermediate to N3-phosphohistidine

The [32P]uridylyl-enzyme intermediate form of Escherichia coli galactose-1-P uridylyltransferase can be converted to a [32P]phosphoryl-enzyme by first cleaving the ribosyl ring with NaIO4 and then heating at pH 10.5 and 50 degrees C for 1 h. After alkaline hydrolysis of the [32P]phosphoryl-enzyme the major radioactive product is N3-[32P]phosphohistidine. A lesser amount of 32Pi is also produced as a side product of the hydrolysis of N3-[32P]phosphohistidine. No N1-phosphohistidine, N-phospholysine, or phosphoarginine can be detected in these hydrolysates. It is concluded that the nucleophile in galactose-1-P uridylyltransferase to which the uridylyl group is bonded in the uridylyl-enzyme intermediate is imidazole N3 of a histidine residue. This degradation procedure should have general applicability in the degradation and characterization of nucleotidyl-proteins.

Studies on a rat-liver cell-sap protein yielding 3-[32P]-phosphohistidine after incubation with [32P]ATP and alkaline hydrolysis. Identification of the protein as ATP citrate lyase

1. The rat-liver cell-sap material from which 3-[32P]phosphohistidine was previously isolated after incubation with [gamma-32P]ATP and alkaline hydrolysis, was shown to increase about 6-fold on a high-carbohydrate diet. This increase in 32P labelling corresponded to the increase in ATP citrate lyase activity of livers of rats fed on a high-carbohydrate diet, as reported by others. 2. ATP citrate lyase [ATP:citrate oxaloacetate-lyase (CoA-acetylating and ATP-dephopshorylating), EC 4.1.3.8] was purified from rat liver essentially according to the method of Plowman and Cleland (J. Biol. Chem., 242 (1967) 4239). The purified enzyme was incubated for a short time at 0 degree with [gamma-32P]ATP in the presence of 20 mM magnesium acetate. The phosphorylated protein was hydrolysed in alkali and the main part of the radioactivity was identified as 3-[32P]phosphohistidine. The identity of the phosphorylated amino acid was established by Dowex-1 chromatography, paper electrophoresis, paper chromatography and by analysis of the stability to acid. 3. It is concluded from these and previous results from this laboratory that ATP citrate lyase and nucleoside diphosphate kinase (ATP:nucleoside diphosphate phosphotransferase, EC 2.7.4.6) account for most of the normal rat-liver cell-sap protein which is rapidly phosphorylated by ATP.