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Catalytically-inactive β-amylase BAM4 required for starch breakdown in Arabidopsis leaves is a starch-binding-protein
Citation
Li, J and Francisco, P and Zhou, W and Edner, C and Steup, M and Ritte, G and Bond, CS and Smith, SM, Catalytically-inactive β-amylase BAM4 required for starch breakdown in Arabidopsis leaves is a starch-binding-protein, Archives of Biochemistry and Biophysics, 489, (1-2) pp. 92-98. ISSN 0003-9861 (2009) [Refereed Article]
Copyright Statement
© 2009 Elsevier Inc. All rights reserved.
DOI: doi:10.1016/j.abb.2009.07.024
Abstract
Of the four chloroplast β-amylase (BAM) proteins identified in Arabidopsis, BAM3 and BAM4 were previously shown to play the major roles in leaf starch breakdown, although BAM4 apparently lacks key active site residues and β-amylase activity. Here we tested multiple BAM4 proteins with different N-terminal sequences with a range of glucan substrates and assay methods, but detected no α-1,4-glucan hydrolase activity. BAM4 did not affect BAM1, BAM2 or BAM3 activity even when added in 10-fold excess, nor the BAM3-catalysed release of maltose from isolated starch granules in the presence of glucan water dikinase. However, BAM4 binds to amylopectin and to amylose–Sepharose whereas BAM2 has very low β-amylase activity and poor glucan binding. The low activity of BAM2 may be explained by poor glucan binding but absence of BAM4 activity is not. These results suggest that BAM4 facilitates starch breakdown by a mechanism involving direct interaction with starch or other α-1,4-glucan.
Item Details
Item Type: | Refereed Article |
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Keywords: | catalyst, starch, arabidopsis thaliana |
Research Division: | Biological Sciences |
Research Group: | Plant biology |
Research Field: | Plant physiology |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the biological sciences |
UTAS Author: | Smith, SM (Professor Steven Smith) |
ID Code: | 101476 |
Year Published: | 2009 |
Web of Science® Times Cited: | 31 |
Deposited By: | Plant Science |
Deposited On: | 2015-06-24 |
Last Modified: | 2015-09-22 |
Downloads: | 0 |
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