TY - JOUR
T1 - Allosteric regulation of DNA cleavage and sequence-specificity through run-on oligomerization
AU - Lyumkis, Dmitry
AU - Talley, Heather
AU - Stewart, Andrew
AU - Shah, Santosh
AU - Park, Chad K.
AU - Tama, Florence
AU - Potter, Clinton S.
AU - Carragher, Bridget
AU - Horton, Nancy C.
PY - 2013/10/8
Y1 - 2013/10/8
N2 - SgrAI is a sequence specific DNA endonuclease that functions through an unusual enzymatic mechanism that is allosterically activated 200- to 500-fold by effector DNA, with a concomitant expansion of its DNA sequence specificity. Using single-particle transmission electron microscopy to reconstruct distinct populations of SgrAI oligomers, we show that in the presence of allosteric, activating DNA, the enzyme forms regular, repeating helical structures characterized by the addition of DNA-binding dimeric SgrAI subunits in a run-on manner. We also present the structure of oligomeric SgrAI at 8.6 Å resolution, demonstrating the conformational state of SgrAI in its activated form. Activated and oligomeric SgrAI displays key protein-protein interactions near the helix axis between its N termini, as well as allosteric protein-DNA interactions that are required for enzymatic activation. The hybrid approach reveals an unusual mechanism of enzyme activation that explains SgrAI's oligomerization and allosteric behavior.
AB - SgrAI is a sequence specific DNA endonuclease that functions through an unusual enzymatic mechanism that is allosterically activated 200- to 500-fold by effector DNA, with a concomitant expansion of its DNA sequence specificity. Using single-particle transmission electron microscopy to reconstruct distinct populations of SgrAI oligomers, we show that in the presence of allosteric, activating DNA, the enzyme forms regular, repeating helical structures characterized by the addition of DNA-binding dimeric SgrAI subunits in a run-on manner. We also present the structure of oligomeric SgrAI at 8.6 Å resolution, demonstrating the conformational state of SgrAI in its activated form. Activated and oligomeric SgrAI displays key protein-protein interactions near the helix axis between its N termini, as well as allosteric protein-DNA interactions that are required for enzymatic activation. The hybrid approach reveals an unusual mechanism of enzyme activation that explains SgrAI's oligomerization and allosteric behavior.
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U2 - 10.1016/j.str.2013.08.012
DO - 10.1016/j.str.2013.08.012
M3 - Article
C2 - 24055317
AN - SCOPUS:84885411813
VL - 21
SP - 1848
EP - 1858
JO - Structure with Folding & design
JF - Structure with Folding & design
SN - 0969-2126
IS - 10
ER -