Crystal structure of Gig2 protein from Candida albicans provides a structural insight into DUF1479 family oxygenases

Abstract

Candida albicans, GlcNAc inducible gene 2 (Gig2) is important for its virulence, oxidative stress adaptation and is supposed to be a part of the undefined GlcNAc metabolic network. On the basis of sequence homology, Gig2 is classified as a putative oxidoreductase of DUF1479 family (Domain of Unknown Function) with no reported structure and function. In this work, we have elucidated the crystal structure of Gig2 protein using X-ray crystallography at 1.7 Å resolution. Crystals were improved using successive macro-seeding technique. Structure was solved by molecular replacement using a template (PDBID: 2CSG) with a mere 27% identity with Gig2, followed by manual and automated model building. Gig2 exists as a monomer with a single large DUF1479 domain and is composed of a cupin like double stranded β-helix (DBSH) core fold with Iron (Fe) in the active site. This is the first report of DUF1479 family proteins which identifies and highlights its unique structural features. Crystal structure elucidation, structural comparisons, and docking studies proposes Gig2 as a non-heme Fe (II) containing 2-oxoglutarate dependent oxygenase.