Circular dichroism, thermal denaturation, and deoxyribonuclease I digestion studies of nucleosomes highly enriched in high mobility group proteins HMG 1 and HMG 2

Journal Article · Thu Jan 01 04:00:00 EST 1981 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00507a060· OSTI ID:6933516

Jackson, J B; Rill, R L

Salt-soluble (S) nucleosomes that contain near equimolar high mobility group nonhistone chromosomal proteins HMG 1 and HMG 2 and lack histone H1 were isolated from mouse myeloma nuclei. Comparisons of the sedimentation, near-uv circular dichroism, thermal denaturation, and pattern of DNase I digestion of S nucleosomes with these properties of nucleosome cores or ''typical'' nucleosomes containing H1 did not detect significant differences, these results indicate that HMG 1 and 2 do not affect the conformation and stability of nucleosomes or nucleosomal DNA and are consistent with the proposal that major functions of HMG 1 and 2 are to replace H1 and maintain the (micro) solubility and accessibility of local chromatin regions. In contrast to these similarities, the initial rate of DNase I digestion of S nucleosomes was approx. 3 times that of chromatin depleted in s nucleosomes. This is consistent with a relation of S nucleosomes to transcription and suggests that subtle factors (not necessarily HMG 1 and 2) determine DNase I susceptibility.

• Research Organization: Florida State Univ., Tallahassee
• OSTI ID: 6933516
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 20:4; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
CHROMATIN
DICHROISM
DIGESTION
DNA
HISTONES
MAMMALS
MICE
NUCLEIC ACIDS
NUCLEOSOMES
ORGANIC COMPOUNDS
PROTEIN DENATURATION
PROTEINS
RODENTS
SEDIMENTATION
TEMPERATURE EFFECTS
TUMOR CELLS
VERTEBRATES