11bg

A POTENTIAL ALLOSTERIC SUBSITE GENERATED BY DOMAIN SWAPPING IN BOVINE SEMINAL RIBONUCLEASE

spinqualitylabelsall models 11bg, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 11bg is a 2 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4, U2G Activity: Pancreatic ribonuclease, with EC number 3.1.27.5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RNS_BOVIN] This enzyme hydrolyzes both single- and double-stranded RNA. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Bovine seminal ribonuclease (BS-RNase) is a peculiar member of the pancreatic-like ribonuclease superfamily endowed with unique biological functions. It has been shown that native BS-RNase is a mixture of two distinct dimeric forms. The most abundant form is characterised by the swapping of the N-terminal helix. Kinetic studies have shown that this dimer is allosterically regulated, whereas the minor component, in which no swapping occurs, exhibits typical Michaelian kinetics. In order to correlate the catalytic properties with the structural features of BS-RNase, we have determined the crystal structure of the BS-RNase swapping dimer complexed with uridylyl(2'-5')guanosine. The structure of the complex was refined to an R value of 0.189 at 1.9 A resolution. Surprisingly, the enzyme binds four dinucleotide molecules, all in a non-productive way. In the two active sites, the guanine base is located in the subsite that is specific for pyrimidines. This unusual binding has been observed also in complexes of RNase A with guanine-containing nucleotides (retro-binding). One of the two additional dinucleotide molecules bound to the enzyme is located on the surface of the protein in a pocket generated by crystal packing; the second was found in a cavity at the interface between the two subunits of the swapping dimer. There are indications that the interface site plays a role in the allosteric regulation exhibited by BS-RNase. This finding suggests that domain swapping may not merely be a mechanism that proteins adopt for the transition from a monomeric to oligomeric state but can be used to achieve modulations in catalytic function. A potential allosteric subsite generated by domain swapping in bovine seminal ribonuclease.,Vitagliano L, Adinolfi S, Sica F, Merlino A, Zagari A, Mazzarella L J Mol Biol. 1999 Oct 29;293(3):569-77. PMID:10543951 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease 3D structures

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