TETRAHYMENA HISTONE-H4 - COMPLETE AMINO-ACID-SEQUENCES OF 2 VARIANTS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 96  (5) , 1449-1456
Abstract
The H4 histone of the protozoan Tetrahymena pyriformis, as obtained previously, was completely sequenced; the total sequence reported preliminarily is one of the 2 variant sequences determined here. The intact H4 was directly sequenced by automated Edman degradation from the N-terminal through residue 92. Sequence determination was further performed with tryptic peptides and peptic peptides, both covering the whole sequences. Thus, the complete sequences of 2 variants were determined; both consist of a total of 102 amino acid residues, have identical compositions, have the same MW of 11,228 in the unmodified form, and are partially acetylated at 4 lysine residues from the N-terminal. The sequences differ in 2 positions from each other (-Lys-Arg-Arg-Lys- at residues 19 and 20, 7:3 mol/mol), and in 22 or 20 positions from the human spleen H4 sequence. The implications of these results for the structure-function relationship of this histone species and also for the phylogeny of protozoa are discussed.