Figure 6.

ACL5 encodes a spermine synthase involved in polyamine biosynthesis. A, Genomic structure of the ACL5 gene. Exons are indicated by black boxes. Asterisk indicates the missing nucleotide in tkv allele. B, Alignment of the deduced amino acid sequences of ACL5, AtSPDS1, AtSPDS2, AtSPMS, and Thermotoga maritima spermidine synthase (for which a crystal structure was solved [Korolev et al., 2002]). Amino acids affected by the tkv mutation are underlined, and the Glu residue mutated in acl5-1 allele is marked with an asterisk.