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Characterizing Y532H disease‐causing mutation and N‐terminal domains of the human Wilson protein
Author(s) -
MUIA JOSHUA,
Huffman David,
Banci Lucia,
Bertini Ivano,
Wang Shenlin
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.521.5
Subject(s) - mutant , mutation , chemistry , wild type , protein structure , crystallography , protein folding , menkes disease , heteronuclear single quantum coherence spectroscopy , circular dichroism , copper , biophysics , biology , genetics , gene , biochemistry , stereochemistry , nuclear magnetic resonance spectroscopy , copper metabolism , organic chemistry
The human Wilson protein (ATP7B) is a copper transporting ATPase that is involved in copper homeostasis. Mutations in the gene coding for this protein leads to Wilson Disease (WD), a hepatological disorder characterized by impaired excretion of copper in bile. We characterized Y532H disease‐causing mutant, and its interaction with a copper chaperone, HAH1 (also known as Atox1). We examined structural effects of Y532H mutation in domains 5 and 6 wild type construct of ATP7B. It was found that the mutation alters the solubility of the expressed protein, decrease overall protein stability as observed by circular dichroism (CD) spectroscopy and does not interfere with copper binding. The 15 N HSQC experiments by NMR reveal an essentially folded protein, a phenomenon also supported by CD experiments. The amide chemical shifts are highly similar between the wild type and mutant WLN5‐6 for the domain 6 (G80‐Q149), as shown by chemical shift variation (CSV) data, and the most affected amino residues are those spatially close to mutation which includes Q4‐F7, K47‐H(Y)48 (mutation) and V52‐I53. In conclusion, the Y532H mutation is perceived to perturb the hydrogen bond network in domain 5, which is critical for a compact structure, thus inducing motions on the side chains and break the linkage between two domains, causing inter‐domain motion and structural heterogeneity, which is absent in the wild type. (This work was supported by Wilson's disease Association grant)