High impact information on HMGN1

• Its amino acid sequence is similar (36% amino acid identity) to that of HMG1, while its size and selective extraction with ethidium bromide are similar to properties of the HMG 14 and 17 class of proteins [1].
• On the basis of reverse-phase high performance liquid chromatography and amino acid analysis, HMG 14, serine 99 represents the low affinity phosphorylation site [2].
• TSH treatment enhanced phosphorylation at serine residues in four prominent tryptic phosphopeptides which were identical with those derived from HMG 14 phosphorylated in vitro with cAMP- and cGMP-dependent protein kinases [3].
• HMG 14 and HMG 17 also contained minor sites which could be phosphorylated by cGMP-dependent protein kinase [4].
• These correspond to 6%, 0%, 12%, 20%, and 16% sequence difference between HMG-1 and the other five HMG proteins, although the immunological distance between HMG-1 and HMG-14 may be too large to allow a good correlation between the sequence and the immunological reaction [5].

Biological context of HMGN1

• In this report, we employed mass spectrometry and examined both the extent and the sites of phosphorylation in HMGN1 protein catalyzed by recombinant human protein kinase CK2 [6].
• Acid hydrolysis of the phosphorylated HMG 14 and subsequent analysis by chromatography and high-voltage electrophoresis indicated that the phosphorylated amino acid residue in HMG 14 is phosphoserine [7].

Anatomical context of HMGN1

• The non-histone proteins HMG-1, HMG-2, HMG-3, HMB-8, HMG-14, and HMG-17 (Goodwin, G. H., SANDERS, C., and Johns, E. W. (1973) Eur. J. Biochem. 38, 14) were purified from calf thymus [5].
• The sites of phosphorylation were analyzed by partial acid hydrolysis and by two-dimensional mapping of tryptic digests of 32P-labeled HMG 14 which was purified from control and TSH-treated thyroid tissue [3].

Associations of HMGN1 with chemical compounds

• We found that five serine residues, i.e., Ser6, Ser7, Ser85, Ser88, and Ser98, in HMGN1 can be phosphorylated by the kinase in vitro [6].
• Several tryptic peptides isolated from HMG 14 and 17 which retained the periodate reactivity had in common lysine residues, suggesting a potential modification of the straightepsilon-amino groups of lysines such as nonenzymatic glycation [8].
• The effect of phosphorylation on the affinity of HMG 14 from calf thymus for single-stranded DNA (ssDNA) was studied, using a cyclic GMP-dependent protein kinase from bovine lung and a nuclear protein kinase II from rat liver [9].
• At low ionic strength protein HMG-14 binds to DNA by weak attachment of the N-terminal half of the molecule and is released by 0.3 M NaCl, the ionic strength at which the protein is extracted from chromatin [10].
• Mono S chromatography also enhances the purity of calf thymus HMG 14 prepared by perchloric acid extraction, acetone and ethanol precipitations, and CM-Sephadex chromatography [11].

Enzymatic interactions of HMGN1

• HMG 14 phosphorylated by both A-kinase and NII-kinase eluted from double-stranded DNA-columns almost identically (190 mM NaCl) with the unphosphorylated protein [12].

Other interactions of HMGN1

• Equal numbers of HMG-14 molecules can substitute for HMG-17 and generate the same nucleosome components [13].
• In one step, this technique separates the phosphorylated derivative from A-kinase, ATP, unphosphorylated HMG 14, and a minor phosphorylated by-product which evidence suggests may be the previously reported Ser 6, 24-diphospho-HMG 14 [11].
• Adding higher concentrations of HMG 14 did not affect the ligation pattern of cohesive-ended DNA, while higher concentrations of protamine inhibit the formation of multimers [14].
• Structural studies on two high-mobility-group proteins from calf thymus, HMG-14 and HMG-20 (ubiquitin), and their interaction with DNA [10].

Analytical, diagnostic and therapeutic context of HMGN1

• We have used affinity chromatography to study the effects of phosphorylation of calf thymus high-mobility-group proteins HMG 14 and HMG 17 on their binding properties towards calf thymus single- and double-stranded DNA and histone H1 [12].

References