The purpose of this project is the molecular, biochemical and biophysical characterization of the recently discovered chimeric protein, Androglobin (Hoogewijs, D. et al. (2011) Mol. Biol. Evol.). This chimeric protein consists of an N-terminal calpain-like domain, an internal, circular permutated globin domain, an IQ calmodulin-binding motif and an unknown carboxyterminal domain. Interestingly, the globin domain, which normally consists of eight consecutive α-helices (named A-H), is circularly permuted and split into two parts within androglobin. Androglobin is predominantly expressed in testis tissue of human and mice, more specifically in the post-meiotic phases of spermatogenesis. Therefor a role in spermatogenesis is suggested. In this project a structural and functional analysis of the protein will be performed. The ligand binding and protease activity of the full protein and of the separate domains will be performed. The structural characteristics of the protein will be studied using spectroscopy and X-ray diffraction analysis. Furthermore, the role of androglobine in spermatogenesis will be studied by determining the gene expression of sperm samples and testis biopsies. Because of this interdisciplinary approach, we hope to contribute to the unraveling of the function of this interesting protein.