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Biophysical Characterization of Metal‐Deficient SOD5
Author(s) -
WaningerSaroni Jessica,
Gleason Julie,
Taylor Alexander,
Holloway Stephen,
Culotta Valeria,
Hart John,
Galaleldeen Ahmad
Publication year - 2015
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.29.1_supplement.895.8
Subject(s) - zinc , superoxide dismutase , chemistry , copper , metal , protein subunit , denaturation (fissile materials) , extracellular , crystallography , dismutase , metalloprotein , biophysics , enzyme , biochemistry , biology , nuclear chemistry , organic chemistry , gene
Superoxide dismutase 1 (SOD1) is a homodimeric copper‐zinc containing enzyme that protects cells against oxidative damage through the rapid neutralization of reactive oxygen species (ROS). Its catalytic activity is dependent on the presence of a copper cofactor while zinc is important for its structural stability. Each subunit exhibits two extended loops, the zinc loop and the electrostatic loop, which both become disordered in the absence of zinc. SOD5 is a recently discovered extracellular copper‐only SOD found in the opportunistic pathogenic fungus Candida albicans that enables it to evade the host's immune response. SOD5 lacks the electrostatic loop but retains an ordered zinc loop even in the absence of zinc. In this study we determined the crystal structure of metal‐deficient SOD5. The protein was overexpressed in E. coli and found to be insoluble, necessitating denaturation, refolding, and further purification. SOD5 was stripped of metals, analyzed using sedimentation velocity experiments, concentrated, and crystallized. The crystal structure was determined by molecular replacement using SOD5‐Cu as a search model. Here we report that metal occupancy does not affect the oligomerization state of SOD5 and does not alter the tertiary structure of the molecule.