Alignment of the conserved active-site region of various GWDs. The region surrounding the active-site histidine (marked with asterisk) and the regulatory CFATC sequence of potato GWD are shown. The putative regulatory disulfides are shown in boldface. GenBank protein accession nos. are as follows: potato GWD, AAK11735; Arabidopsis GWD1, AAG47821; citrus GWD, AAM18228; Arabidopsis GWD2, AAO42141; Ostreococus GWD, AAS88899; Arabidopsis GWD3, AAU93516; Chlamydomonas GWDb, BF866967/AW661031.