Document Detail

A comparison of DNA compaction by arginine and lysine peptides: a physical basis for arginine rich protamines.
MedLine Citation:
PMID:  23540557     Owner:  NLM     Status:  MEDLINE    
Protamines are small, highly positively charged peptides used to package DNA at very high densities in sperm nuclei. Tight DNA packing is considered essential for the minimization of DNA damage by mutagens and reactive oxidizing species. A striking and general feature of protamines is the almost exclusive use of arginine over lysine for the positive charge to neutralize DNA. We have investigated whether this preference for arginine might arise from a difference in DNA condensation by arginine and lysine peptides. The forces underlying DNA compaction by arginine, lysine, and ornithine peptides are measured using the osmotic stress technique coupled with X-ray scattering. The equilibrium spacings between DNA helices condensed by lysine and ornithine peptides are significantly larger than the interhelical distances with comparable arginine peptides. The DNA surface-to-surface separation, for example, is some 50% larger with polylysine than with polyarginine. DNA packing by lysine rich peptides in sperm nuclei would allow much greater accessibility to small molecules that could damage DNA. The larger spacing with lysine peptides is caused by both a weaker attraction and a stronger short-range repulsion relative to that of the arginine peptides. A previously proposed model for binding of polyarginine and protamine to DNA provides a convenient framework for understanding the differences between the ability of lysine and arginine peptides to assemble DNA.
Jason DeRouchey; Brandon Hoover; Donald C Rau
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Intramural     Date:  2013-04-18
Journal Detail:
Title:  Biochemistry     Volume:  52     ISSN:  1520-4995     ISO Abbreviation:  Biochemistry     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-04-30     Completed Date:  2013-07-01     Revised Date:  2014-05-07    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3000-9     Citation Subset:  IM    
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MeSH Terms
Arginine / chemistry*
DNA / chemistry*
Lysine / chemistry*
Nucleic Acid Conformation
Peptides / chemistry*
Protamines / chemistry*
Scattering, Radiation
Grant Support
Reg. No./Substance:
0/Peptides; 0/Protamines; 9007-49-2/DNA; 94ZLA3W45F/Arginine; K3Z4F929H6/Lysine

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