Functional Characterization of Arabidopsis α-Amylase3 (AMY3): Amylose Specificity and Structural Insights into Its Duplex Carbohydrate-Binding Module.

ABSTRACT: Flowering plants contain a plastid-localized ɑ-amylase (AMY3) with several recognized domains: two N-terminal carbohydrate-binding modules, an alpha-alpha hairpin that binds the catalytically inactive activator β-amylase9, and a C-terminal catalytic domain. Despite considerable research on leaf starch metabolism in Arabidopsis, little is known about the function of AMY3. Starch is composed of two glucose polymers: highly branched amylopectin (70-90%) and largely unbranched amylose (10-30%). Because ɑ-amylases are endo-amylases, we predicted that AMY3 might prefer to hydrolyze amylose, in contrast to the exo-amylase β-amylase1 (BAM1), which we predicted would prefer amylopectin. Using iodine spectroscopy, we observed that AMY3 caused the percent amylose of corn starch to decrease, whereas B

SUBMITTER: Rahman R 

PROVIDER: S-EPMC12458248 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature