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XB-ART-56533
Chembiochem January 1, 2019; 20 (1): 78-82.

Histone Tail Sequences Balance Their Role in Genetic Regulation and the Need To Protect DNA against Destruction in Nucleosome Core Particles Containing Abasic Sites.

Yang K , Greenberg MM .


Abstract
Abasic sites (AP) are produced 10 000 times per day in a single cell. Strand cleavage at AP is accelerated ≈100-fold within a nucleosome core particle (NCP) compared to free DNA. The lysine-rich N-terminal tails of histone proteins catalyze single-strand breaks through a mechanism used by base-excision-repair enzymes, despite the general dearth of glutamic acid, aspartic acid, and histidine-the amino acids that are typically responsible for deprotonation of Schiff base intermediates. Incorporating glutamic acid, aspartic acid, or histidine proximal to lysine residues in histone N-terminal tails increases AP reactivity as much as sixfold. The rate acceleration is due to more facile DNA cleavage of Schiff-base intermediates. These observations raise the possibility that histone proteins could have evolved to minimize the presence of histidine, glutamic acid, and aspartic acid in their lysine-rich N-terminal tails to guard against enhancing the toxic effects of DNA damage.

PubMed ID: 30307690
PMC ID: PMC6317330
Article link: Chembiochem
Grant support: [+]


References [+] :
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