RRC ID 4846
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.
Abstract 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.
Volume 8
Pages 120
Published 2008-11-27
DOI 10.1186/1471-2229-8-120
PII 1471-2229-8-120
PMID 19038037
PMC PMC2653042
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
IF 3.67
Times Cited 9
Arabidopsis / Cultured plant cells, genes pda04554