ESR studies of conformation and chromatin binding of double labeled lysine-rich histones using isotopically substituted spinlabels

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5233561

Byvoet, P; Barber, M J; Trudeau, W L

The conformation and nucleosomal binding of LH have been studied by ESR, using a tyrosine-specific imidazole spinlabel (IMDSL) which binds to 1 tyrosine-specific imidazole spinlabel (IMDSL) which binds to 1 tyrosine (72) in H-1 and 3 (28, 53, 58) in H-5, all located in the spherical, non-polar portions of these molecules. Sensitivity, resolution and utility of the IMDSL probe was significantly improved by the use of IMDSL substituted with /sup 2/H and either /sup 14/N or /sup 15/N in the nitroxide moiety. H-1 or H-5 labeled with /sup 2/H or /sup 2/H/sup 15/N-IMDSL showed a 5-10 x increased signal amplitude and decreased linewidth, as compared with LH labeled with non-isotopic IMDSL. Spectra of LH mixtures, carrying differential labels showed well resolved peaks, corresponding to both /sup 2/H-IMDSL (3 lines) and /sup 2/H/sup 15/N-IMDSL (2 lines), indicating weak immobilization. The spectra were not significantly affected by changes in ionic strength. Upon proteolytic digestion of thus spinlabeled LH, immobilization was reduced 50%. The use of different isotopically substituted IMDSL will permit, e.g. the simultaneous use of differentially labeled H-1 and H-5 in nucleosomal binding studies. The authors will report the effect of a number of conditions, such as varying salt concentrations, on the conformation of thus labeled LH, as well as LH depleted chromatin, reconstituted with spinlabeled LH.

• Research Organization: Univ. of South Florida, Tampa
• OSTI ID: 5233561
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
HISTONES
BIOCHEMICAL REACTION KINETICS
DOUBLE LABELLING
DEUTERIUM
ELECTRON SPIN RESONANCE
IMIDAZOLES
NITROGEN 15
AZOLES
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LABELLING
LIGHT NUCLEI
MAGNETIC RESONANCE
NITROGEN ISOTOPES
NUCLEI
NUCLEOPROTEINS
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
REACTION KINETICS
RESONANCE
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques