Goodsell Sandbox
From Proteopedia
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{{STRUCTURE_1rta | PDB=1rta | SCENE=Goodsell_Sandbox/Ribonuclease_catalytic_site/1 }} | {{STRUCTURE_1rta | PDB=1rta | SCENE=Goodsell_Sandbox/Ribonuclease_catalytic_site/1 }} | ||
| - | + | Ribonuclease A Active Site | |
| - | + | Ribonuclease A cleaves RNA strands by catalyzing a transphosphorylation reaction where the 2'-OH of the ribose sugar attacks the neighboring phosphate, releasing the ribose on the the other side of the phosphate. This structure shows ribonuclease A bound to short DNA strand composed of four thymidines. Ribonuclease binds tightly to DNA, but since DNA is missing the 2'-OH, ribonuclease does not cleave it. <scene name='Goodsell_Sandbox/Ribonuclease_catalytic_site/1'>Three amino acids</scene> are shown that are important for catalysis. The 3' carbon is shown in red--it is the site where the 2'-OH is connected in RNA. The two histidines perform the proton transfers that are needed in the reaction, and the lysine stabilizes the intermediate that is formed as the 2'-OH attacks the phosphate. Ribonuclease cleaves cytidine and uridine best--the reason for this may be seen in a spacefilling representation. Notice that the small pyrimidine base is surrounded by protein atoms. A larger purine base would not fit well in this space. | |
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<scene name='Goodsell_Sandbox/Ribonuclease_catalytic_site/1'>TextToBeDisplayed</scene> | <scene name='Goodsell_Sandbox/Ribonuclease_catalytic_site/1'>TextToBeDisplayed</scene> | ||
Revision as of 17:18, 19 August 2008
Ribonuclease A Active Site Ribonuclease A cleaves RNA strands by catalyzing a transphosphorylation reaction where the 2'-OH of the ribose sugar attacks the neighboring phosphate, releasing the ribose on the the other side of the phosphate. This structure shows ribonuclease A bound to short DNA strand composed of four thymidines. Ribonuclease binds tightly to DNA, but since DNA is missing the 2'-OH, ribonuclease does not cleave it. are shown that are important for catalysis. The 3' carbon is shown in red--it is the site where the 2'-OH is connected in RNA. The two histidines perform the proton transfers that are needed in the reaction, and the lysine stabilizes the intermediate that is formed as the 2'-OH attacks the phosphate. Ribonuclease cleaves cytidine and uridine best--the reason for this may be seen in a spacefilling representation. Notice that the small pyrimidine base is surrounded by protein atoms. A larger purine base would not fit well in this space.
