Biochemical and functional characterization of histone H1-like proteins in procyclic Trypanosoma brucei brucei.
Four variants and/or posttranslational modifications of histone H1-like proteins of Trypanosoma brucei brucei procyclic culture forms were extracted with 0.25 N HCl from isolated nuclei and analyzed by two-dimensional gel electrophoresis. The amino acid composition of these proteins, their ability to space nucleosomes regularly and to induce salt-dependent condensation of the chromatin indicated their histone H1 nature. On the other hand, the histone H1-like proteins clearly differed from their higher-eukaryote counterparts by their weak interaction with DNA under low-salt conditions. As a consequence, intact nucleosome filaments were prepared according to a new preparation protocol especially adapted to the unstable chromatin of T. b. brucei. Our results indicate that the biochemical properties of the histone H1-like proteins contribute to the structural and functional differences between the chromatin of procyclic T. b. brucei and that of higher eukaryotes.
Burri
M
M
Swiss Tropical Institute, Basel.
Schlimme
W
W
Betschart
B
B
Kämpfer
U
U
Schaller
J
J
Hecker
H
H
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002843:Chromatin / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D016054:DNA, Protozoan / Q000378:metabolism; D006657:Histones / Q000302:isolation & purification* / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism / Q000648:ultrastructure; D011485:Protein Binding; D014346:Trypanosoma brucei brucei / Q000737:chemistry* / Q000648:ultrastructure
D000596:Amino Acids; D002843:Chromatin; D016054:DNA, Protozoan; D006657:Histones; D009707:Nucleosomes