4OQ4

Crystal Structure of E18A Human DJ-1

Summary for 4OQ4

• Entry DOI: 10.2210/pdb4oq4/pdb
• Related: 1SOA 3CY6 3CYF 3CZA
• Descriptor: Protein DJ-1, SODIUM ION (3 entities in total)
• Functional Keywords: cysteine-sulfinic acid, chaperone
• Biological source: Homo sapiens (human)
• Cellular location: Cell membrane; Lipid-anchor: Q99497
• Total number of polymer chains: 1
• Total formula weight: 20196.28

Authors

Prahlad, J.,Hauser, D.N.,Milkovic, N.M.,Cookson, M.R.,Wilson, M.A. (deposition date: 2014-02-07, release date: 2014-02-19, Last modification date: 2024-11-20)

Primary citation

Prahlad, J.,Hauser, D.N.,Milkovic, N.M.,Cookson, M.R.,Wilson, M.A.
Use of cysteine-reactive cross-linkers to probe conformational flexibility of human DJ-1 demonstrates that Glu18 mutations are dimers.
J Neurochem, 130:839-853, 2014

PubMed Abstract: The oxidation of a key cysteine residue (Cys106) in the parkinsonism-associated protein DJ-1 regulates its ability to protect against oxidative stress and mitochondrial damage. Cys106 interacts with a neighboring protonated Glu18 residue, stabilizing the Cys106-SO2 (-) (sulfinic acid) form of DJ-1. To study this important post-translational modification, we previously designed several Glu18 mutations (E18N, E18D, E18Q) that alter the oxidative propensity of Cys106. However, recent results suggest these Glu18 mutations cause loss of DJ-1 dimerization, which would severely compromise the protein's function. The purpose of this study was to conclusively determine the oligomerization state of these mutants using X-ray crystallography, NMR spectroscopy, thermal stability analysis, circular dichroism spectroscopy, sedimentation equilibrium ultracentrifugation, and cross-linking. We found that all of the Glu18 DJ-1 mutants were dimeric. Thiol cross-linking indicates that these mutant dimers are more flexible than the wild-type protein and can form multiple cross-linked dimeric species due to the transient exposure of cysteine residues that are inaccessible in the wild-type protein. The enhanced flexibility of Glu18 DJ-1 mutants provides a parsimonious explanation for their lower observed cross-linking efficiency in cells. In addition, thiol cross-linkers may have an underappreciated value as qualitative probes of protein conformational flexibility. DJ-1 is a homodimeric protein that protects cells against oxidative stress. Designed mutations that influence the regulatory oxidation of a key cysteine residue have recently been proposed to disrupt DJ-1 dimerization. We use cysteine cross-linking and various biophysical techniques to show that these DJ-1 mutants form dimers with increased conformational flexibility.

PubMed: 24832775
DOI: 10.1111/jnc.12763

Experimental method

X-RAY DIFFRACTION (1.49 Å)