Sandbox 154: Difference between revisions

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The state of the bound phosphorylated nucleotide affects what conformation the F-actin monomer undertakes. The presence of a gamma-phosphate in the active site causes the rotation of a Ser14 residue. This change leads to a methylated histidine (HIC73) becoming shifted, which alters the F-actin active site and causes a conformational change in the D-loop. The HIC73 is located in the sensor loop, or the "switch" for linking changes in bound nucleotide to conformational changes<ref name="Graceffa"/>. In ATP-actin and ADP-P<sub>i</sub>-actin, the D-loop is unstructured. In the ADP-bound form of F-actin, an alpha helix is commonly apparent in the D-loop of the monomer<ref name="Pfaendtner"/><ref name="Graceffa"/>.   
The state of the bound phosphorylated nucleotide affects what conformation the F-actin monomer undertakes. The presence of a gamma-phosphate in the active site causes the rotation of a Ser14 residue. This change leads to a methylated histidine (HIC73) becoming shifted, which alters the F-actin active site and causes a conformational change in the D-loop. The HIC73 is located in the sensor loop, or the "switch" for linking changes in bound nucleotide to conformational changes<ref name="Graceffa"/>. In ATP-actin and ADP-P<sub>i</sub>-actin, the D-loop is unstructured. In the ADP-bound form of F-actin, an alpha helix is commonly apparent in the D-loop of the monomer<ref name="Pfaendtner"/><ref name="Graceffa"/>.   


Although the alpha-helix is not observed in this Oda model of F-actin and is not seen in some other F-actin studies<ref name=”oda”/><ref name=”dalhaimer”>PMID: 18155236</ref>, it is acknowledged by Oda et. al that the experimental results could have lead to an extended alpha-helix in the model<ref name="oda"/>.  
Although the alpha-helix is not observed in this Oda model of F-actin and is not seen in some other F-actin studies<ref name=”Oda”/><ref name=”Dalhaimer”>PMID:18155236</ref>, it is acknowledged by Oda et. al that the experimental results could have lead to an extended alpha-helix in the model<ref name="oda"/>.  


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