Scholarlink

<p>Sialic acids are a diverse family of acidic sugars typically found at the terminal positions of glycan chains, mediating key physiological and pathological processes across animals - particularly vertebrates - including cell signaling and host-pathogen interactions. The distribution of sialic acids in lower animals such as mollusks, however, remains largely unresolved. Here, we report the discovery of unconjugated 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), a deaminated analogue of <i>N</i>-acetylneuraminic acid, in the muscle tissue of Pacific oysters (<i>Magallana gigas</i>). Using UPLC-ESI-MS/MS fingerprinting, we identified naturally occurring free KDN at a concentration of 1.2 ± 0.1 nmol/100&#xa0;mg of oyster muscle tissue. To investigate the biosynthetic pathway, four candidate genes were identified in the <i>M. gigas</i> genome, and the corresponding recombinant proteins were expressed and characterized. Enzymatic assays revealed that one putative sialic acid aldolase (MgNPL) specifically catalyzes the cleavage of KDN into mannose and pyruvate. To our knowledge, this represents the first molecular evidence of KDN metabolism in mollusks and highlights both the unexpected conservation of substrate-specific aldolase activity and distinct sialic acid utilization mechanisms compared to vertebrates.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Identification of a distinct sialic acid (KDN) and a KDN-specific aldolase in Pacific oyster

  • 期刊论文

  • 发表日期：

    2025年12月19日

查看全文
  • Zi-Xuan Hu,
  • Jia-Yu Zhang,
  • Jitske van Ede,
  • Yao-Yao Zhang,
  • Yu-Quan Li,
  • Mattia Ghirardello,
  • M. Carmen Galan,
  • Martin Pabst,
  • Li Liu,
  • Josef Voglmeir

摘要

Sialic acids are a diverse family of acidic sugars typically found at the terminal positions of glycan chains, mediating key physiological and pathological processes across animals - particularly vertebrates - including cell signaling and host-pathogen interactions. The distribution of sialic acids in lower animals such as mollusks, however, remains largely unresolved. Here, we report the discovery of unconjugated 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), a deaminated analogue of N-acetylneuraminic acid, in the muscle tissue of Pacific oysters (Magallana gigas). Using UPLC-ESI-MS/MS fingerprinting, we identified naturally occurring free KDN at a concentration of 1.2 ± 0.1 nmol/100 mg of oyster muscle tissue. To investigate the biosynthetic pathway, four candidate genes were identified in the M. gigas genome, and the corresponding recombinant proteins were expressed and characterized. Enzymatic assays revealed that one putative sialic acid aldolase (MgNPL) specifically catalyzes the cleavage of KDN into mannose and pyruvate. To our knowledge, this represents the first molecular evidence of KDN metabolism in mollusks and highlights both the unexpected conservation of substrate-specific aldolase activity and distinct sialic acid utilization mechanisms compared to vertebrates.