Identification of three proteins up-regulated by raw starch in Cytophaga sp.
- PDF / 367,555 Bytes
- 5 Pages / 595 x 791 pts Page_size
- 62 Downloads / 168 Views
ORIGINAL PAPER
IdentiWcation of three proteins up-regulated by raw starch in Cytophaga sp. Rong-Jen Shiau · Yu-Der Wen · Chii-Ling Jeang
Received: 12 April 2008 / Revised: 6 July 2008 / Accepted: 17 July 2008 / Published online: 15 August 2008 © Springer-Verlag 2008
Abstract Raw starch-digesting amylases (RSDAs) in many microorganisms convert starch granules into maltodextrins and simple sugars. We cloned and sequenced from Cytophaga sp. an RSDA with an excellent raw starch digestion activity. This RSDA was highly inducible by raw starch, but not by other sugars, suggesting that an unknown signal transduction mechanism is involved in the degradation of raw starch. We used a proteomic approach to investigate the eVect of raw starch on protein expression in Cytophaga sp. Using MALDI–TOF MS protein analysis, we have identiWed three proteins up-regulated by raw starch, i.e., a 60-kDa chaperonin (cpn60), glutaminase, and pyruvate phosphate dikinase (PPDK). Subsequent timecourse studies detected an increased expression of RSDA as well as the highest expression of PPDK occurring 6 h post-incubation with raw corn starch, implying that the latter enzyme may work along with RSDA on the digestion of raw starch. Finding these proteins up-regulated by raw starch may provide an insight into how Cytophaga sp. cells respond to raw starch stimulation.
Communicated by Jorge Membrillo-Hernández. R.-J. Shiau (&) Department of Beauty Science, Chienkuo Technology University, Changhua 500, Taiwan e-mail: [email protected] Y.-D. Wen Department of Biology, National Changhua University of Education, Changhua 500, Taiwan C.-L. Jeang Department of Food Science, National Chung Hsing University, Taichung 400, Taiwan
Keywords Cytophaga sp. · Raw starch · Two dimensional-gel electrophoresis Abbreviations CBB Coomassie Brilliant Blue R250 cpn60 60-kDa chaperonin GWD -Glucan, water dikinase IEF Isoelectric focusing MALDI Matrix-assisted laser desorption ionization PPDK Pyruvate, phosphate dikinase RSDA Raw-starch-digesting amylase 2-DE Two dimensional-gel electrophoresis
Introduction Starch, the major carbohydrate source in the world, is synthesized and stored in granulated form in plants. Starch granules are semi-crystalline particles composed of amyloses, which are linear chains of -1, 4-linkaged glucose units, and high branched amylopectin, which are polysaccharides with an -1, 4-backbone and -1, 6-branched points (Blennow et al. 2002). Many starch digesting enzymes have been identiWed to date. For example, -amylases (1,4--D-glucan glycanohydrolase, EC3.2.1.1) randomly cleave -1,4-glucosidic bonds in starch, forming oligosaccharides; -amylases (EC 3.2.1.2) and glucoamylases (EC 3.2.1.3) hydrolyze starch from its non-reducing end and produce maltose and glucose (Pandey et al. 2000). These enzymes are widely used in the food industry for starch processing (Biwer et al. 2002; van der Maarel et al. 2002). In order to improve the conversion of starch molecules into simple sugars by amylolytic enzymes, starch granules have to be gelatiniz
Data Loading...
