1js0

From Proteopedia

proteopedia linkproteopedia link

spinqualitylabelsall models 1js0, resolution 2.2Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure of 3D Domain-swapped RNase A Minor Trimer

Overview

When concentrated in mildly acidic solutions, bovine pancreatic, ribonuclease (RNase A) forms long-lived oligomers including two types of, dimer, two types of trimer, and higher oligomers. In previous, crystallographic work, we found that the major dimeric component forms by, a swapping of the C-terminal beta-strands between the monomers, and that, the minor dimeric component forms by swapping the N-terminal alpha-helices, of the monomers. On the basis of these structures, we proposed that a, linear RNase A trimer can form from a central molecule that simultaneously, swaps its N-terminal helix with a second RNase A molecule and its, C-terminal strand with a third molecule. Studies by dissociation are, consistent with this model for the major trimeric component: the major, trimer dissociates into both the major and the minor dimers, as well as, monomers. In contrast, the minor trimer component dissociates into the, monomer and the major dimer. This suggests that the minor trimer is, cyclic, formed from three monomers that swap their C-terminal beta-strands, into identical molecules. These conclusions are supported by cross-linking, of lysyl residues, showing that the major trimer swaps its N-terminal, helix, and the minor trimer does not. We verified by X-ray crystallography, the proposed cyclic structure for the minor trimer, with swapping of the, C-terminal beta-strands. This study thus expands the variety of, domain-swapped oligomers by revealing the first example of a protein that, can form both a linear and a cyclic domain-swapped oligomer. These, structures permit interpretation of the enzymatic activities of the RNase, A oligomers on double-stranded RNA.

About this Structure

1JS0 is a Single protein structure of sequence from Bos taurus with SO4 as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.

Reference

Structures of the two 3D domain-swapped RNase A trimers., Liu Y, Gotte G, Libonati M, Eisenberg D, Protein Sci. 2002 Feb;11(2):371-80. PMID:11790847

Page seeded by OCA on Tue Nov 20 18:32:03 2007