Potential for interactions between the carboxy‐ and amino‐termini of Rubisco activase subunits

FEBS Letters

Salvucci, Michael E.¹ 

[1] US Department of Agriculture, Agricultural Research Service, Western Cotton Research Laboratory, 4135 E. Broadway Road, Phoenix, AZ 85040-8803, USA

关键词: AAA+ protein;    ATPase;    Carbon metabolism;    Cross-linking;    Photosynthesis;    BMOE;    bis-maleimidoethane;    DTT;    dithiothreitol;    I-NBD;    N;    N′-dimethyl-N-(iodoacetyl)-N′-(7-nitrobenz-2-oxa-1;    3-diazol-4-yl)ethylenediamine;    NBD;    nitrobenz-2-oxa-1;    3-diazole;    RuBP;    ribulose 1;    5-bisphosphate;    Rubisco;    ribulose-1;    5-bisphosphate carboxylase/oxygenase;   

DOI  :  10.1016/S0014-5793(04)00111-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The subunit interactions of Rubisco activase were investigated using mutants containing an introduced Cys near the N- and/or C-terminus. Chemical cross-linking of the C-terminal and double insertion mutant produced subunit dimers and dimers plus high ordered oligomers, respectively. Fluorescence measurements with N,N′-dimethyl-N-(iodoacetyl)-N′-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)ethylenediamine showed that the environment around the introduced Cys near the C-terminus becomes more hydrophilic upon nucleotide binding. The Cys insertion mutants catalyzed Rubisco activation and ATP hydrolysis even when the subunits of the C-terminal or double insertion mutants were completely cross-linked. The results indicate that the termini of adjacent activase subunits are in close proximity and can be modified and even joined without affecting enzyme function.

【 授权许可】

Unknown