Example sentences for: abasic

How can you use “abasic” in a sentence? Here are some example sentences to help you improve your vocabulary:

  • The importance of such bonds for activity was shown in other work, where huAPE1's binding to the DNA backbone is only inhibited by ethylation of the phosphates two and three positions 3' to an abasic site [ 18 ] . Mutation of R177A, at the end of Molego 6, that binds to this region and to the bases opposite the AP-site had enhanced activity [ 11 ] , while mutations at W280 (Molego 11) and F266 (Molego 10) [ 33 ] reduce activity and, in the latter case, substrate selectivity.

  • This redundancy of binding to the 3' side is unique to APE, as is its strong binding to the DNA opposite the abasic site.

  • Of the four protein areas that bind to the DNA 3' of the abasic site, mutating F266 (molego 10) or W280 (middle of molego 11) decreases APE activity [ 33 ] . The F266 mutation is particularly interesting, as the mutants at this position had reduced substrate specificity and enhanced 3'-exonuclease activity.

  • This generates the necessary 3' hydroxyl group for DNA polymerases (pol β, δ or ε, in eukaryotes) to insert the correct nucleotide in later steps in the base excision repair pathway (BER-pathway) [ 7 8 ] . Recent crystal structures of huAPE1 complexed with DNA containing an abasic site [ 9 10 11 ] , combined with sequence analysis and site-directed mutagenesis, have defined the residues that participate in metal ion based cleavage of the phosphate backbone of the DNA [ 12 13 14 15 16 17 ] .

  • For example, Herschlag and co-workers have previously shown that a nucleobase could complement an abasic site within the hammerhead ribozyme, restoring cleavage activity [ 1 ] . Similarly, Porta and Lizardi engineered a hammerhead ribozyme that assumed an inactive secondary structure; upon the addition of an oligonucleotide that disrupted the engineered secondary structure, the ribozyme was activated [ 2 ] . More recently, it has previously been shown that many selected nucleic acid binding species (aptamers) undergo conformational changes upon ligand binding [ 3 4 5 6 ] In addition, when aptamers are conjoined to ribozymes, the ligand-induced conformational changes in the aptamers frequently modulate the structures and hence the activities of the ribozymes [ 7 8 9 ] For example, binding of theophylline to the anti-theophylline aptamer [ 10 ] modulates the conformation of residue [ 11 12 ] and the overall stability of the aptamer [ 10 13 ] . Appending the anti-theophylline aptamer to the hammerhead ribozyme allowed cleavage activity to be modulated by 110-fold by theophylline [ 13 ] . Similarly, appending the anti-theophylline aptamer to a small ribozyme ligase (L1) generated an aptazyme that was activated 1,600-fold by saturating theophylline concentrations [ 14 ] .

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