The molybdenum cofactor (Moco) is a redox active prosthetic group found in the active site of Moco dependent enzymes (Mo-enzymes). As Moco and its intermediates are highly sensitive towards oxidative damage, these are believed to be permanently protein bound during synthesis and upon maturation. As a major component of the plant Moco transfer and storage system, proteins have been identified that are capable of Moco binding and release but do not possess Moco dependent enzymatic activities. The first protein found to possess these properties was the Moco carrier protein (MCP) from the green alga Chlamydomonas reinhardtii. Here, we describe the identification and biochemical characterization of the Volvox carteri (V. carteri) MCP and, for the first time, employ a comparative analysis to elucidate the principles behind MCP Moco binding. Doing so identified a sequence region of low homology amongst the existent MCPs which we showed to be essential for Moco binding to V. carteri MCP.

中文翻译：

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团藻 Moco 载体蛋白的鉴定和表征。


钼辅因子 (Moco) 是在 Moco 依赖性酶（Mo 酶）活性位点发现的氧化还原活性辅基。由于 Moco 及其中间体对氧化损伤高度敏感，因此相信它们在合成过程中和成熟后会永久结合蛋白质。作为植物 Moco 转移和储存系统的主要组成部分，已鉴定出能够结合和释放 Moco 但不具有 Moco 依赖性酶活性的蛋白质。第一个被发现具有这些特性的蛋白质是来自绿藻莱茵衣藻的 Moco 载体蛋白 (MCP)。在这里，我们描述了Volvox carteri (V. carteri) MCP的鉴定和生化特征，并首次采用比较分析来阐明MCP Moco结合背后的原理。这样做确定了现有 MCP 中同源性较低的序列区域，我们证明该区域对于 Moco 与 V. carteri MCP 的结合至关重要。