Intramolecular localization and effect on conformational stability in vitro of irreversible interphase phosphorylation of Physarum histone H1

Journal Article · Tue Oct 21 04:00:00 EDT 1986 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00369a023· OSTI ID:6527671

Jerzmanowski, A; Krezel, A M

To elucidate the intramolecular localization of irreversible interphase phosphorylation of Physarum histone H1 and its effect on H1,s conformational properties, the circular dichroism spectra, the pH- and salt-dependent folding, and the products of trypsin digestion for the interphase phosphorylated (with five to nine phosphates per molecule) and enzymatically dephosphorylated H1 were compared. Both phosphorylated and dephosphorylated H1 show similar amounts of helicity at high ionic strength and upon limited digestion with trysin form identical trypsin-resistant peptides of the size slightly larger than the analogous peptide from calf thymus H1. The circular dichroism analysis of the pH-dependent folding of Physarum H1 in water shows a strong effect of phosphorylation on the folding process in both the acidic and alkaline pH region. The analysis of the products of trypsin digestion of (/sup 32/P) PO/sub 4/-labeled Physarum H1 before and after enzymatic dephosphorylation is consistent with the interpretation that the interphase phosphorylation occurs predominantly within the 50-70 amino acid sequence directly adjacent to the trypsin-resistant peptide on its C-terminal side and that this sequence is itself involved in some kind of loose folding at high ionic strength. The studies of the formation of the trypsin-resistant peptide (the globular domain) as a function of salt concentration show that it is induced at 300 mM lower NaCl concentration for phosphorylated than for dephosphorylated H1. These results indicate that the stable, interphase phosphorylation of Physarum H1 enhances the salt-induced formation of the folded globular region in vitro. This conclusion together with the finding that only nonphosphorylated H1 occurs in the DNase I solubilized fraction of Physarum chromatin may be relevant for a mechanism of chromatin activation in Physarum.

• Research Organization: Warsaw Univ., Poland
• OSTI ID: 6527671
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 25:21; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CELL DIVISION
CHEMICAL ACTIVATION
CHEMICAL REACTIONS
CHROMATIN
CONFORMATIONAL CHANGES
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DICHROISM
DNA-ASE
ENZYMATIC HYDROLYSIS
ENZYMES
ESTERASES
FUNGI
HISTONES
HYDROLASES
HYDROLYSIS
IN VITRO
ISOTOPES
LIGHT NUCLEI
LYSIS
MAGNETIC CIRCULAR DICHROISM
MITOSIS
NUCLEI
NUCLEOPROTEINS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PH VALUE
PHOSPHATES
PHOSPHODIESTERASES
PHOSPHORUS 32
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PHYSARUM
PLANTS
PROTEINS
RADIOISOTOPES
SOLVOLYSIS