Independence of carbon and nitrogen control in the posttranslational regulation of nitrate transport in the cyanobacterium Synechococcus sp. strain PCC 7942

FEBS Letters

Kobayashi, Masaki²  Omata, Tatsuo²  Rodrı́guez, Rocı́o¹  Lara, Catalina¹ 

[1]Dept. de Bioquı́mica Vegetal y Biologı́a Molecular, Facultad de Biologı́a, Universidad de Sevilla, Apdo. 1095, E-41080 Sevilla, Spain

[2]Dept. of Applied Biological Sciences, School of Agricultural Sciences, Nagoya University, Nagoya 464-01, Japan

关键词: Nitrate transport;    Posttranslational control;    Cyanobacterium;    DLG;    d;    l-glyceraldehyde;    GA;    glycolaldehyde;    MSX;    l-methionine d;    l-sulfoximine;    NiR;    nitrite reductase;    NR;    nitrate reductase;    NT;    nitrate transport;   

DOI  :  10.1016/S0014-5793(98)00865-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Nitrate transport by Synechococcus sp. strain PCC 7942 cells was inhibited by ammonium and by inhibitors of CO₂ fixation. Ammonium assimilation inhibitors, such as l-methionine d,l-sulfoximine, were known to prevent the negative effects of ammonium and of inhibitors of CO₂ fixation on nitrate uptake, leading to propose that CO₂ fixation was required to counteract the feed-back inhibition of nitrate assimilation. In NR-less mutants, l-methionine d,l-sulfoximine prevented the negative effects of ammonium on nitrate transport, but not always prevented those of inhibiting CO₂ fixation. The carboxy-terminal domain of the NrtC subunit of the nitrate transporter has recently been identified as a regulatory domain involved in N-control. The mutant strain NC2, constructed by deleting the 3′ portion of nrtC, showed high nitrate transport activity insensitive to ammonium but sensitive to inhibitors of CO₂ fixation. These findings indicate that the C-control and the N-control of nitrate transport are independent at both the physiological and the molecular level.

【 授权许可】

Unknown