1pw3
From Proteopedia
|
Crystal structure of JtoR68S
Overview
Primary (AL) amyloidosis results from the pathologic deposition of, monoclonal light chains as amyloid fibrils. Studies of recombinant-derived, variable region (VL) fragments of these proteins have shown an inverse, relationship between thermodynamic stability and fibrillogenic potential., Further, ionic interactions within the VL domain were predicted to, influence the kinetics of light chain fibrillogenicity, as evidenced from, our analyses of a relatively stable Vlambda6 protein (Jto) with a long, range electrostatic interaction between Asp and Arg side chains at, position 29 and 68, respectively, and an unstable, highly fibrillogenic, Vlambda6 protein (Wil) that had neutral amino acids at these locations. To, test this hypothesis, we have generated two Jto-related mutants designed, to disrupt the interaction between Asp 29 and Arg 68 (JtoD29A and, JtoR68S). Although the thermodynamic stabilities of unfolding for these, two molecules were identical, they exhibited very different kinetics of, fibril formation: the rate of JtoD29A fibrillogenesis was slow and, comparable to the parent molecule, whereas that of JtoR68S was, significantly faster. High-resolution X-ray diffraction analyses of, crystals prepared from the two mutants having the same space group and, unit cell dimensions revealed no significant main-chain conformational, changes. However, several notable side-chain alterations were observed in, JtoR68S, as compared with JtoD29A, that resulted in the solvent exposure, of a greater hydrophobic surface and modifications in the electrostatic, potential surface. We posit that these differences contributed to the, enhanced fibrillogenic potential of the Arg 68 mutant, since both Jto, mutants lacked the intrachain ionic interaction and were equivalently, unstable. The information gleaned from our studies has provided insight, into structural parameters that in addition to overall thermodynamic, stability, contribute to the fibril forming propensity of immunoglobulin, light chains.
About this Structure
1PW3 is a Protein complex structure of sequences from Homo sapiens with CD as ligand. Full crystallographic information is available from OCA.
Reference
Structural basis of light chain amyloidogenicity: comparison of the thermodynamic properties, fibrillogenic potential and tertiary structural features of four Vlambda6 proteins., Wall JS, Gupta V, Wilkerson M, Schell M, Loris R, Adams P, Solomon A, Stevens F, Dealwis C, J Mol Recognit. 2004 Jul-Aug;17(4):323-31. PMID:15227639
Page seeded by OCA on Sun Nov 25 03:06:31 2007
