Table 1.

A brief characteristics of histone H5 and chromatin protein MENT

Histone H5 (189 amino acids; 20.5 kDa)	MENT (410 amino acids; 42 kDa)
Nuclear localization and functionality
Histone H5 is deposited in terminally differentiated erythrocytes (~1.4 molecule/nucleosome) forming large-scale condensed and repressed heterochromatic regions (Thomas et al. 1992; Bednar et al. 1998; Koutzamani et al. 2002)	MENT is deposited in non-red blood cells (granulocytes ~2 molecules/200 bp of DNA) forming condensed and repressed chromatin (Grigoryev and Woodcock 1998)
Domain organization and molecular structure
N-terminal domain (1–21 aa), C-terminal domain (101–189 aa), and globular domain (22–100 aa) containing winged-helix fold consisting of three helix bundles (H1 29–38aa, H2 48–58aa, H3 65–78aa) and two strands of β-ribbon (81–85aa and 93–96aa) (Briand et al. 1980; Ramakrishnan et al. 1993)	M-loop domain (61–91 aa), NLS domain (80–84 aa), and RCL domain (352–379 aa). The molecule adopts α/β fold comprised of nine α-helices (hA–hI) and three β-sheets (A–C) (Grigoryev et al. 1999; McGowan et al. 2006)
DNA binding sites
Two DNA binding sites on the globular domain: a primary binding site (Lys69, Arg73, and Lys85), and a secondary binding site (Lys40, Arg42, Lys52, Arg94) (Goytisolo et al. 1996; Duggan and Thomas 2000)	Two DNA binding sites on the M-loop domain: One site around AT-hook motif and the second site around D- and E-helices (McGowan et al. 2006)
Mechanism of action
One-step formation of compacted chromatin fibers by cooperative binding of globular domains to DNA with a subsequent dimerization inducing stem-like structures needed for chromatin folding (Bednar et al. 1998; Thomas et al. 1992)	Two-step formation of compacted chromatin fibers by initial binding to DNA and folding the nucleosome array by M-loop domains and further bridging the separate arrays by RCL domains to create self-associated chromatin fibers (Grigoryev 2001; Springhetti et al. 2003)