A) Aligned amino acid sequences for Fcp1 FCPH domains from S. pombe, S. cerevisiae, C. albicans, D. melanogaster, C. elegans, H. sapiens, M. musculus, X. laevis, A. thaliana, and E. cuniculi and H.sapiens Scp1. SpFcp1 and Scp1 secondary structure elements are color-coded as in Fig. 1 above the sequence or shown in grey below the sequence, respectively (helices as bars; strands as arrows). Short alignment gaps indicated by (−). The disordered 72-amino acid loop (SpFcp1 aa 326-397) denoted as a break (//) in the alignment. Results of previous and current mutational analysis of SpFcp1 are indicated by circles above selected amino acids colored according to the relative activities of the respective mutants as specified by the color bar above panel B. B) Stereo diagram of the Fcp1 active site depicting amino acids subjected to mutational analysis. Side chains as sticks color-coded according to the phosphatase activity of the respective alanine mutant. Magnesium and water are depicted as blue and red spheres, respectively. Atomic contacts indicated by dashed lines. The polypeptide backbone is represented by a thin ribbon.