| First Author | Roque A | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 37 | Pages | 32141-7 |
| PubMed ID | 16006555 | Mgi Jnum | J:240283 |
| Mgi Id | MGI:5882893 | Doi | 10.1074/jbc.M505636200 |
| Citation | Roque A, et al. (2005) DNA-induced secondary structure of the carboxyl-terminal domain of histone H1. J Biol Chem 280(37):32141-7 |
| abstractText | We have studied the secondary structure of the carboxyl-terminal domains of linker histone H1 subtypes H1(0) (C-H1(0)) and H1t (C-H1t), free in solution and bound to DNA, by IR spectroscopy. The carboxyl-terminal domain has little structure in aqueous solution but becomes extensively folded upon interaction with DNA. The secondary structure elements present in the bound carboxyl-terminal domain include the alpha-helix, beta-structure, turns, and open loops. The structure of the bound domain shows a significant dependence on salt concentration. In low salt (10 mm NaCl), there is a residual amount of random coil, 7% in C-H1(0) and 12% in C-H1t. In physiological salt concentrations (140 mm NaCl), the carboxyl termini become fully structured. Under these conditions, C-H1(0) contained 24% alpha-helix, 25% beta-structure, 17% open loops, and 33% turns. The latter component could include a substantial proportion of the 3(10) helix. Despite their low sequence identity (approximately 30%), the representation of the different structural motifs in C-H1t was similar to that in C-H1(0). Examination of the changes in the amide I components in the 20-80 degrees C temperature interval showed that the secondary structure of the DNA-bound C-H1t is for the most part extremely stable. The H1 carboxyl-terminal domain appears to belong to the so-called disordered proteins, undergoing coupled binding and folding. |
