Motohashi Shoko, Jimbo Mitsuru, Naito Tomohiro, Suzuki Takefumi, Sakai Ryuichi, Kamiya Hisao
Department of Marine Biosciences, School of Marine Biosciences, Kitasato University,1-15-1, Minami-ku, Kitasato, Sagamihara, Kanagawa 252-0373, Japan.
Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan.
Mar Drugs. 2017 Jun 2;15(6):161. doi: 10.3390/md15060161.
Egg lectins occur in a variety of animals ranging from mollusks to vertebrates. A few examples of molluscan egg lectins have been reported, including that of the sea hare ; however, their biological functions in the egg remain unclarified. We report the isolation, determination of primary structure, and possible functions of lectin (AKL) from the egg mass of . We obtained AKL as an inseparable mixture of isoproteins with a relative molecular mass of approximately 32 kDa by affinity purification. The hemagglutinating activity of AKL against rabbit erythrocytes was inhibited most potently by galacturonic acid and moderately by xylose. Nucleotide sequencing of corresponding cDNA obtained by rapid amplification of cDNA ends (RACE) allowed us to deduce complete amino acid sequences. The mature polypeptides consisted of 218- or 219-amino acids with three repeated domains. The amino acid sequence had similarities to hypothetical proteins of spp., or domain DUF3011 of uncharacterized bacterial proteins. AKL is the first member of the DUF3011 family whose function, carbohydrate recognition, was revealed. Treatment of the egg with galacturonic acid, an AKL sugar inhibitor, resulted in deformation of the veliger larvae, suggesting that AKL is involved in organogenesis in the developmental stage of .
卵凝集素存在于从软体动物到脊椎动物的多种动物中。已经报道了一些软体动物卵凝集素的例子，包括海兔的卵凝集素；然而，它们在卵中的生物学功能仍不清楚。我们报告了从[物种名称]卵块中分离凝集素（AKL）、确定其一级结构以及探讨其可能功能的研究。我们通过亲和纯化获得了AKL，它是一种相对分子质量约为32 kDa的同型蛋白不可分离的混合物。AKL对兔红细胞的血凝活性最有效地被半乳糖醛酸抑制，被木糖中度抑制。通过cDNA末端快速扩增（RACE）获得的相应cDNA的核苷酸测序使我们能够推断出完整的氨基酸序列。成熟多肽由218或219个氨基酸组成，具有三个重复结构域。氨基酸序列与[物种名称]的假定蛋白或未表征细菌蛋白的结构域DUF3011相似。AKL是DUF3011家族中第一个其功能（碳水化合物识别）被揭示的成员。用半乳糖醛酸（一种AKL糖抑制剂）处理卵导致担轮幼虫变形，这表明AKL参与了[物种名称]发育阶段的器官发生。
