The GS‐GOGAT pathway is not operative in the heterocysts. Cloning and expression of glsF gene from the cyanobacterium Anabaena sp. PCC 7120

FEBS Letters

Florencio, Francisco J.¹  Martı́n-Figueroa, Eugenio¹  Navarro, Francisco¹ 

[1]Instituto de Bioquı́mica Vegetal y Fotosı́ntesis, Universidad de Sevilla-CSIC, Centro de Investigaciones Cientı́ficas Isla de la Cartuja, Avda Américo Vespucio, s/n, 41092 Sevilla, Spain

关键词: GS-GOGAT;    Nitrogen assimilation;    Heterocyst;    Cyanobacterium;   

DOI  :  10.1016/S0014-5793(00)01722-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The gene encoding the ferredoxin-dependent glutamate synthase (Fd-GOGAT), glsF, from the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120, has been cloned and sequenced. Unlike other cyanobacteria, Anabaena 7120 contains only Fd-GOGAT, lacking NADH-GOGAT. The amount of glsF transcript and Fd-GOGAT activity were similar under all the nitrogen growth conditions tested. Enzyme activity, Western and Northern blot analyses indicated that Fd-GOGAT is absent in the heterocysts, while glutamine synthetase (GS) and NADP-isocitrate dehydrogenase (IDH) were present in these specialised cells. Our results clearly indicate that the GS-GOGAT pathway is not operative in the heterocysts, and hence glutamate must be imported from the adjacent vegetative cells, to sustain GS activity. Heterocysts probably export glutamine or another nitrogen rich compound like arginine to the vegetative cells.

【 授权许可】

Unknown