Biomaterial Database

Alpha-helix in the carboxy-terminal domains of histones H1 and H5. 1988

D J Clark, and C S Hill, and S R Martin, and J O Thomas

Department of Biochemistry, University of Cambridge, London, UK.

Although the carboxy-terminal domains of histones H1 and H5 exist as random-coil in aqueous solution, secondary structure prediction suggests that this region has a high potential for alpha-helix formation. We have measured CD spectra in various conditions known to stabilize alpha-helices, to determine whether this potential can be realized in an appropriate environment. Trifluoroethanol increases the helix contents of H1, H5 and their carboxy-terminal fragments, presumably through promotion of axial hydrogen bonding. Sodium perchlorate is also effective and better than sodium chloride, suggesting stabilization by binding of bulky perchlorate ions rather than simple charge screening. Extrapolating from these measurements in solution, and taking into account the occurrence of proline residues throughout the carboxy-terminal domain, we propose that binding to DNA stabilizes helical segments in the carboxy-terminal domains of histones H1 and H5, and that it is this structured form of the domain that is functionally important in chromatin.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006657	Histones	Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.	Histone,Histone H1,Histone H1(s),Histone H2a,Histone H2b,Histone H3,Histone H3.3,Histone H4,Histone H5,Histone H7
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012617	Sea Urchins	Somewhat flattened, globular echinoderms, having thin, brittle shells of calcareous plates. They are useful models for studying FERTILIZATION and EMBRYO DEVELOPMENT.	Echinoidea,Sand-Dollar,Clypeasteroida,Sand Dollars,Clypeasteroidas,Dollar, Sand,Dollars, Sand,Echinoideas,Sand Dollar,Sand-Dollars,Sea Urchin,Urchin, Sea,Urchins, Sea
D013094	Spermatozoa	Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.	Sperm,Spermatozoon,X-Bearing Sperm,X-Chromosome-Bearing Sperm,Y-Bearing Sperm,Y-Chromosome-Bearing Sperm,Sperm, X-Bearing,Sperm, X-Chromosome-Bearing,Sperm, Y-Bearing,Sperm, Y-Chromosome-Bearing,Sperms, X-Bearing,Sperms, X-Chromosome-Bearing,Sperms, Y-Bearing,Sperms, Y-Chromosome-Bearing,X Bearing Sperm,X Chromosome Bearing Sperm,X-Bearing Sperms,X-Chromosome-Bearing Sperms,Y Bearing Sperm,Y Chromosome Bearing Sperm,Y-Bearing Sperms,Y-Chromosome-Bearing Sperms
D014644	Genetic Variation	Genotypic differences observed among individuals in a population.	Genetic Diversity,Variation, Genetic,Diversity, Genetic,Diversities, Genetic,Genetic Diversities,Genetic Variations,Variations, Genetic