Department of Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, 72076 Tübingen, Germany.
Int J Mol Sci. 2022 Mar 29;23(7):3752. doi: 10.3390/ijms23073752.
is a soil bacterium living in a habitat with very changeable nutrient availability. This organism possesses a complex nitrogen metabolism and is able to utilize the polyamines putrescine, cadaverine, spermidine, and spermine and the monoamine ethanolamine. We demonstrated that GlnA2 (SCO2241) facilitates to survive under high toxic polyamine concentrations. GlnA2 is a gamma-glutamylpolyamine synthetase, an enzyme catalyzing the first step in polyamine catabolism. The role of GlnA2 was confirmed in phenotypical studies with a deletion mutant as well as in transcriptional and biochemical analyses. Among all GS-like enzymes in , GlnA2 possesses the highest specificity towards short-chain polyamines (putrescine and cadaverine), while its functional homolog GlnA3 (SCO6962) prefers long-chain polyamines (spermidine and spermine) and GlnA4 (SCO1613) accepts only monoamines. The genome-wide RNAseq analysis in the presence of the polyamines putrescine, cadaverine, spermidine, or spermine revealed indication of the occurrence of different routes for polyamine catabolism in involving GlnA2 and GlnA3. Furthermore, GlnA2 and GlnA3 are differently regulated. From our results, we can propose a complemented model of polyamine catabolism in , which involves the gamma-glutamylation pathway as well as other alternative utilization pathways.
是一种生活在营养供应非常不稳定的土壤细菌。该生物体具有复杂的氮代谢途径，能够利用腐胺、尸胺、亚精胺和精胺以及单胺乙醇胺。我们证明 GlnA2（SCO2241）有助于在高毒性多胺浓度下生存。GlnA2 是一种γ-谷氨酰多胺合成酶，是一种催化多胺分解代谢第一步的酶。通过缺失突变体的表型研究以及转录和生化分析证实了 GlnA2 的作用。在 中所有 GS 样酶中，GlnA2 对短链多胺（腐胺和尸胺）具有最高的特异性，而其功能同源物 GlnA3（SCO6962）则偏爱长链多胺（亚精胺和精胺），而 GlnA4（SCO1613）只接受单胺。在存在腐胺、尸胺、亚精胺或精胺的情况下进行全基因组 RNAseq 分析表明， 中多胺分解代谢可能存在涉及 GlnA2 和 GlnA3 的不同途径。此外，GlnA2 和 GlnA3 的调控方式也不同。根据我们的结果，我们可以提出一种补充的 多胺分解代谢模型，其中涉及γ-谷氨酰化途径以及其他替代利用途径。
