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Extremely divergent histone H 4 sequence from trypanosoma cruzi : Evolutionary implications
Author(s) -
Toro G. Cecilia,
Wernstedt Christer,
Medina Carlos,
Jaramillo Nicolás,
Hellman Ulf,
Galanti Norbel
Publication year - 1992
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240490309
Subject(s) - histone , biology , histone h4 , tetrahymena , histone h1 , histone code , histone h3 , histone methyltransferase , genetics , histone h2a , histone octamer , peptide sequence , nucleosome , dna , gene
Trypanosoma cruzi presents six histones electrophoretically resolved in three gel systems. Indirect evidence shows that one of these histones, name, corresponds to H 4 in other species. We present evidence that histones is H 4 by sequencing its amino terminal end. The amino terminal of T. cruzi histone H 4 , unlike that of other H 4 s examined thus far is not blocked. Moreover, this protein presents two variants. This partial amino acid sequence of T. cruzi histone H 4 differs greatly from homologous sequences of human, yeast, or Tetrahymena . Since the conservatism of the core histones (H 2 A, H 2 B, H 3 , and H 4 ) is clearly illustrated by comparative sequence analyses, the data shown here demonstrates that T. cruzi histone H 4 is the most divergent reported. Quantitative analysis of the data suggests that the rate of substitutions in the histone H 4 amino terminal sequence varies among different lineages. We postulate a slow‐down in the evolutionary rate of histone H 4 amino terminal domain in the metazoa branch related perhaps to the appearance of a novel function for this domain.