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Structural Characterization of SOD5 Mutants from Candida albicans
Author(s) -
Villarreal Johanna,
Peterson Ryan L.,
Taylor Alexander B.,
Holloway Stephen P.,
Galaleldeen Ahmad,
Culotta Valeria Cizewski,
Hart P. John
Publication year - 2016
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.30.1_supplement.836.6
Subject(s) - candida albicans , superoxide dismutase , reactive oxygen species , mutant , hydrogen peroxide , superoxide , active site , microbiology and biotechnology , chemistry , enzyme , pathogen , escherichia coli , biochemistry , biology , gene
Candida albicans is the most prevalent human fungal pathogen and there is currently no vaccine to fight these infections. Colonization by this microbe can lead to acute infections of the mucosal surfaces in the oral and genital cavities, which for immunocompromised individuals can lead to life‐threatening systemic infections. Superoxide Dismutase (SOD) is an enzyme that catalyzes the dismutation of the superoxide radical into hydrogen peroxide and molecular oxygen. SOD5, a cell surface protein, is used by Candida albicans to defend itself against reactive oxygen species (ROS) released during the host immune response. SOD5 is related to Cu/Zn SODs but the structure shows a copper‐only active site and the protein is lacking the electrostatic loop common to Cu/Zn SODs. To better understand the biophysical characteristics of SOD5, mutants of SOD5 with single amino acid substitutions at positions 110 and 113 were generated to disrupt the hydrogen bonding network that stabilizes the active site. These mutants were over‐expressed in E. coli and, because of their insolubility, were denatured, refolded, purified, and set up for crystallization trials. Data were collected for crystals of the mutants and the structures were determined using the molecular replacement method. The structures reveal that the mutations did not alter binding of copper at the copper site.