Variation in Storage α-Polyglucans of Red Algae: Amylose and Semi-Amylopectin Types in Porphyridium and Glycogen Type in Cyanidium

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• 作者：Takahiro Shimonaga ; Shoko Fujiwara ; Miki Kaneko ; Asako Izumo ; Satoko Nihei ; Perigio B. Francisco ; Aya Satoh ; Naoko Fujita ; Yasunori Nakamura and Mikio Tsuzuki
• 关键词：Amylose ; glycogen ; granule ; bound starch synthase ; red algae ; semi ; amylopectin
• 刊名：Marine Biotechnology
• 出版年：2007
• 出版时间：March, 2007
• 年：2007
• 卷：9
• 期：2
• 页码：192-202
• 全文大小：611 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Oceanography
  
• 出版者：Springer New York
• ISSN：1436-2236

文摘

Red algae are widely known to produce floridean starch but it remains unclear whether the molecular structure of this algal polyglucan is distinct from that of the starch synthesized by vascular plants and green algae. The present study shows that the unicellular species Porphyridium purpureum R-1 (order Porphyridiales, class Bangiophyceae) produces both amylopectin-type and amylose-type α-polyglucans. In contrast, Cyanidium caldarium (order Porphyridiales, class Bangiophyceae) synthesizes glycogen-type polyglucan, but not amylose. Detailed analysis of α-1,4-chain length distribution of P. purpureum polyglucan suggests that the branched polyglucan has a less ordered structure, referred to as semi-amylopectin, as compared with amylopectin of rice endosperm having a tandem-cluster structure. The P. purpureum linear amylose-type polyglucan, which has a λ_max of 630 nm typical of amylose-iodine complex and is resistant to Pseudomonas isoamylase digestion, accounts for less than 10% of the total polyglucans. We produced and isolated a cDNA encoding a granule-bound starch synthase (GBSS)-type protein of P. purpureum, which is probably the approximately 60-kDa protein bound tightly to the starch granules, resembling the amylose-synthesizing GBSS protein of green plants. The present investigation indicates that the class Bangiophyceae includes species producing both semi-amylopectin and amylose, and species producing glycogen alone.