Open AccessThe Conformation of Histone H5
Author(s) -
AVILES Francisco J.,
CHAPMAN George E.,
KNEALE Geoff G.,
CRANEROBINSON Colyn,
BRADBURY E. Morton
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12457.x
Subject(s) - peptide , circular dichroism , crystallography , chemistry , molecule , histone h1 , ionic strength , globular cluster , histone , globular protein , biophysics , nuclear magnetic resonance , biochemistry , physics , biology , aqueous solution , organic chemistry , quantum mechanics , galaxy , gene
Treatment of chicken erythrocyte histone H5 with trypsin in a high‐ionic‐strength medium results in very rapid initial digestion and the formation of a ‘limiting’ resistant product peptide. Under these solution conditions the H5 molecule is maximally folded by spectroscopic criteria and it is concluded that the resistant peptide, GH5, represents a globular folded region of the molecule whilst the rapidly digested parts are disordered. The peptide GH5 is shown to comprise the sequence 22–100. In support of this conclusion it is shown that whilst intact histone H5 is hydrodynamically far from being a compact globular shape, peptide GH5 is approximately spherical by hydrodynamic and scattering criteria. Further more, peptide GH5 retains all the α‐helical structure of intact H5 (circular dichroism) and appears to also maintain all the tertiary structure (nuclear magnetic resonance). It follows that in solution at high ionic strength, histone H5 consists of three domains: an N‐terminal disordered region 1–21, a compact globular central domain 22–100 and a long disordered C‐terminal chain 101–185. Structural parallels are drawn with the three‐domain structure of the histone H1 molecule.