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Model nucleoproteins: Binding of actinomycin D to complexes of DNA with lysine‐containing polypeptides
Author(s) -
Votavoá H.,
Bláha K.,
Šponar J.
Publication year - 1978
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1978.360170710
Subject(s) - chemistry , lysine , dna , titration , nucleoprotein , binding site , histone , helix (gastropod) , amino acid , tris , biochemistry , stereochemistry , organic chemistry , biology , ecology , snail
Complexes of DNA with histone H1 and random and sequential polypeptides containing 30–100% of lysine were studied using actinomycin D as a probe. The binding of actinomycin D was measured by spectrophotometric titration in 0.15 M NaCl and in 0.01 M Tris buffer. The excluded‐site model was used for the evaluation of binding data. Polypeptides reduce the number of binding sites on DNA available for actinomycin D binding. The extent of this change depends mainly on the content and distribution of basic lysine residues. Of the hydrophobic residues constituting the peptides, only leucine strongly depresses the actinomycin D binding. The helix‐forming and helix‐breaking amino acid residues are without effect.