Prediction of an HMG-box fold in the C-terminal domain of histone H1: insights into its role in DNA condensation.
In eukaryotes, histone H1 promotes the organization of polynucleosome filaments into chromatin fibers, thus contributing to the formation of an important structural framework responsible for various DNA transaction processes. The H1 protein consists of a short N-terminal "nose," a central globular domain, and a highly basic C-terminal domain. Structure prediction of the C-terminal domain using fold recognition methods reveals the presence of an HMG-box-like fold. We recently showed by extensive site-directed and deletion mutagenesis studies that a 34 amino acid segment encompassing the three S/TPKK motifs, within the C-terminal domain, is responsible for DNA condensing properties of H1. The position of these motifs in the predicted structure corresponds exactly to the DNA-binding segments of HMG-box-containing proteins such as Lef-1 and SRY. Previous analyses have suggested that histone H1 is likely to bend DNA bound to the C-terminal domain, directing the path of linker DNA in chromatin. Prediction of the structure of this domain provides a framework for understanding the higher order of chromatin organization.
Bharath
M M Srinivas
MM
Department of Biochemistry, Indian Institute of Science, Bangalore, India.
Chandra
Nagasuma R
NR
Rao
M R S
MR
D000595:Amino Acid Sequence; D000818:Animals; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D006609:High Mobility Group Proteins / Q000737:chemistry; D006657:Histones / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013329:Structure-Activity Relationship
D002843:Chromatin; D006609:High Mobility Group Proteins; D006657:Histones; D004247:DNA