ISSN:
1573-4943
Keywords:
histone structure
;
sodium dodecyl sulfate
;
prediction of secondary structure
;
difference spectroscopy
;
spectrofluorometry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The effects of sodium dodecyl sulfate (SDS) on the structure of histones H1 as model proteins have been studied by a combination of difference spectroscopy, circular dichroism (CD), and spectrofluorometry. The detergent increases the α-helix content at the expense of random-coiled regions. As measured by CD, this transition involves 44–50 residues in calf H1. Assuming that positive charges in the amino acid side chains are no longer an impediment to the formation of α-helix in the presence of SDS, the use of the method of prediction of secondary structure elaborated by Chou and Fasman gives an estimate of six regions with high helix-forming potential. One of these peptides lies in the NH2-terminal region (residues 22–29), whereas the five remaining peptides are in the COOH-terminal region of the histone (residues 109–114, 120–125, 142–151, 185–189, and 202–211). These six peptides amount to 45 residues, in good agreement with experimental results. We have also studied the action of the detergent on the environment of tyrosyl residues of calf H1 (one tyrosine) andCeratitis capitata H1 (two tyrosines). Difference spectroscopy and CD show that the environment of tyrosine-72 of calf H1 in the histone-SDS complex differs from both the native state and the acid-denatured state. The two tyrosyl residues ofCeratitis H1, whose environments in the native protein are markedly different, are included in similar environments in the histone-SDS complex.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01025064
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