Reference - Detail
|Author||Lohmeier-Vogel EM, Kerk D, Nimick M, Wrobel S, Vickerman L, Muench DG, Moorhead GB.|
|Title||Arabidopsis At5g39790 encodes a chloroplast-localized, carbohydrate-binding, coiled-coil domain-containing putative scaffold protein.|
|Journal||BMC Plant Biol.|
BACKGROUND:Starch accumulation and degradation in chloroplasts is accomplished by a suite of over 30 enzymes. Recent work has emphasized the importance of multi-protein complexes amongst the metabolic enzymes, and the action of associated non-enzymatic regulatory proteins. Arabidopsis At5g39790 encodes a protein of unknown function whose sequence was previously demonstrated to contain a putative carbohydrate-binding domain.
RESULTS:We here show that At5g39790 is chloroplast-localized, and binds starch, with a preference for amylose. The protein persists in starch binding under conditions of pH, redox and Mg(+2) concentrations characteristic of both the day and night chloroplast cycles. Bioinformatic analysis demonstrates a diurnal pattern of gene expression, with an accumulation of transcript during the light cycle and decline during the dark cycle. A corresponding diurnal pattern of change in protein levels in leaves is also observed. Sequence analysis shows that At5g39790 has a strongly-predicted coiled-coil domain. Similar analysis of the set of starch metabolic enzymes shows that several have strong to moderate coiled-coil potential. Gene expression analysis shows strongly correlated patterns of co-expression between At5g39790 and several starch metabolic enzymes.
CONCLUSION:We propose that At5g39790 is a regulatory scaffold protein, persistently binding the starch granule, where it is positioned to interact by its coiled-coil domain with several potential starch metabolic enzyme binding-partners.
|MeSH||Amino Acid Sequence Arabidopsis / genetics* Arabidopsis / metabolism Arabidopsis Proteins / genetics Arabidopsis Proteins / isolation & purification Arabidopsis Proteins / metabolism* Chloroplasts / metabolism* Cloning, Molecular Gene Expression Regulation, Plant Molecular Sequence Data Oligonucleotide Array Sequence Analysis Protein Binding Sequence Alignment Starch / metabolism* Substrate Specificity Time Factors|
|WOS Category||PLANT SCIENCES|
|Arabidopsis / Cultured plant cells, genes||pda04554|