Ribonuclease
From Proteopedia
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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 (in blue) bound to short DNA strand composed of four thymidines (in pink). 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/2'>Three amino acids</scene> are shown that are important for catalysis. The 3' carbon on the DNA 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 RNA strands best next to cytidine and uridine nucleotides--the reason for this may be seen in a <scene name='Goodsell_Sandbox/Ribonuclease_recognition/2'>spacefilling representation</scene>. Notice that the small pyrimidine base is surrounded by protein atoms. A larger purine base would not fit well in this space.<ref>PMID:1429575</ref> | 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 (in blue) bound to short DNA strand composed of four thymidines (in pink). 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/2'>Three amino acids</scene> are shown that are important for catalysis. The 3' carbon on the DNA 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 RNA strands best next to cytidine and uridine nucleotides--the reason for this may be seen in a <scene name='Goodsell_Sandbox/Ribonuclease_recognition/2'>spacefilling representation</scene>. Notice that the small pyrimidine base is surrounded by protein atoms. A larger purine base would not fit well in this space.<ref>PMID:1429575</ref> | ||
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== 3D Structures of Ribonuclease == | == 3D Structures of Ribonuclease == | ||
Revision as of 11:59, 7 December 2014
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3D Structures of Ribonuclease
Updated on 07-December-2014
References
- ↑ Birdsall DL, McPherson A. Crystal structure disposition of thymidylic acid tetramer in complex with ribonuclease A. J Biol Chem. 1992 Nov 5;267(31):22230-6. PMID:1429575
- Created with the participation of David S. Goodsell, Eric Martz, and Eran Hodis.
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Michal Harel, Alexander Berchansky, Wayne Decatur, David Canner, Joel L. Sussman, Jaime Prilusky
