title: Putative spermine synthases from Thalassiosira pseudonana and Arabidopsis thaliana synthesize thermospermine rather than spermine.
abstract: Polyamines are involved in many fundamental cellular processes. Common polyamines are putrescine, spermidine and spermine. Spermine is synthesized by transfer of an aminopropyl residue derived from decarboxylated S-adenosylmethionine to spermidine. Thermospermine is an isomer of spermine and assumed to be synthesized by an analogous mechanism. However, none of the recently described spermine synthases was investigated for their possible activity as thermospermine synthases. In this work, putative spermine synthases from the diatom Thalassiosira pseudonana and from Arabidopsis thaliana could be identified as thermospermine synthases. These findings may explain the previous result that two putative spermine synthase genes in Arabidopsis produce completely different phenotypes in knock-out experiments. Likely, part of putative spermine synthases identifiable by sequence comparisons represents in fact thermospermine synthases.
authors.affiliation: Lehrstuhl Biochemie I, Universität Regensburg, Regensburg, Germany.
authors.forename: Jürgen M
authors.initials: JM
authors.lastname: Knott
authors.forename: Piero
authors.initials: P
authors.lastname: Römer
authors.forename: Manfred
authors.initials: M
authors.lastname: Sumper
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D017377:Diatoms / Q000201:enzymology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013096:Spermine / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D013097:Spermine Synthase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D013096:Spermine; C021097:thermospermine; D013097:Spermine Synthase