Knott Jürgen M, Römer Piero, Sumper Manfred
Lehrstuhl Biochemie I, Universität Regensburg, Regensburg, Germany.
FEBS Lett. 2007 Jun 26;581(16):3081-6. doi: 10.1016/j.febslet.2007.05.074. Epub 2007 Jun 6.
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.
多胺参与许多基本的细胞过程。常见的多胺有腐胺、亚精胺和精胺。精胺是由脱羧S-腺苷甲硫氨酸衍生的氨丙基残基转移至亚精胺而合成的。热精胺是精胺的一种异构体，推测其通过类似机制合成。然而，最近描述的精胺合成酶中，没有一种被研究其作为热精胺合成酶的潜在活性。在这项研究中，来自硅藻假微型海链藻和拟南芥的假定精胺合成酶可被鉴定为热精胺合成酶。这些发现可能解释了之前的结果，即在拟南芥中两个假定的精胺合成酶基因在敲除实验中产生了完全不同的表型。很可能，通过序列比较可鉴定的部分假定精胺合成酶实际上代表热精胺合成酶。
