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Homospermidine biosynthesis in the cyanobacterium Anabaena requires a deoxyhypusine synthase homologue and is essential for normal diazotrophic growth
- Source :
- Digital.CSIC. Repositorio Institucional del CSIC, instname
- Publication Year :
- 2018
-
Abstract
- Polyamines are primordial, small organic polycations present in almost all cells, but their roles in bacteria are poorly understood. sym‐Homospermidine is the dominant polyamine in the filamentous, N2‐fixing, heterocyst‐forming cyanobacterium Anabaena sp. PCC 7120. Synthesis of homospermidine was dependent on speA (encoding arginine decarboxylase), speB (agmatinase) and speY (deoxyhypusine synthase homologue), which in bacteria is an unprecedented pathway. Inactivation of any of these genes impaired diazotrophic growth. Heterocyst differentiation in the speA mutant was blocked at an early step, after induction of the regulatory gene hetR but before production of heterocyst‐specific glycolipids (HGL). In contrast, the speY mutant produced HGL and showed slow diazotrophic growth. Analysis of fusions to green fluorescent protein revealed that SpeA (like SpeB previously described) accumulates at higher levels in vegetative cells than in heterocysts, and that SpeY accumulates in vegetative cells but also at significant levels in heterocysts. The homospermidine biosynthetic pathway is therefore active primarily in vegetative cells but the last step can be completed in heterocysts. Our findings indicate an important role for polyamines in the diazotrophic biology of Anabaena. Furthermore, inactivation of a gene cluster (potADB) encoding a polyamine ABC transporter disrupted diazotrophic growth, corroborating the importance of polyamine homeostasis in Anabaena.<br />Work was supported by grants number BFU2014‐56757‐P and BFU2017‐88202‐P from Agencia Estatal de Investigación, Spain, co‐financed by the European Regional Development Grant (EF) and by a seed grant from UT Southwestern Medical Center (AJM).
- Subjects :
- 0301 basic medicine
Carboxy-Lyases
Spermidine
Mutant
Cyanobacteria
Microbiology
Ureohydrolases
03 medical and health sciences
chemistry.chemical_compound
Nitrogen fixation
Nitrogen Fixation
Homospermidine biosynthesis
Deoxyhypusine synthase
Molecular Biology
Heterocyst
Oxidoreductases Acting on CH-NH Group Donors
biology
Anabaena
Heterocyst differentiation
biology.organism_classification
Agmatinase
Polyamines
030104 developmental biology
Biochemistry
chemistry
biology.protein
Polyamine homeostasis
ATP-Binding Cassette Transporters
Polyamine
Subjects
Details
- ISSN :
- 13652958
- Volume :
- 109
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- Molecular microbiology
- Accession number :
- edsair.doi.dedup.....d2120b74acce3e24e2eb5948d7f624c8