Marine cyanobacteria are critical players in global nutrient cycles that crucially depend on trace metals in metalloenzymes, including zinc for CO₂ fixation and phosphorus acquisition. How strains proliferating in the vast oligotrophic ocean gyres thrive at ultra-low zinc concentrations is currently unknown. Using Synechococcus sp. WH8102 as a model we show that its zinc-sensor protein Zur differs from all other known bacterial Zur proteins in overall structure and the location of its sensory zinc site. Uniquely, Synechococcus Zur activates metallothionein gene expression, which supports cellular zinc quotas spanning two orders of magnitude. Thus, a single zinc sensor facilitates growth across pico- to micromolar zinc concentrations with the bonus of banking this precious resource. The resultant ability to grow well at both ultra-low and excess zinc, together with overall lower zinc requirements, likely contribute to the broad ecological distribution of Synechococcus across the global oceans.

海洋蓝藻是全球营养循环中的关键参与者，其很大程度上依赖于金属酶中的微量金属，包括用于固定 CO ₂和获取磷的锌。目前尚不清楚在巨大的寡营养海洋环流中增殖的菌株如何在超低锌浓度下茁壮成长。使用聚球藻属。 WH8102 作为模型，我们表明其锌传感器蛋白 Zur 在整体结构和感觉锌位点的位置上不同于所有其他已知的细菌 Zur 蛋白。独特的是，聚球藻Zur 激活金属硫蛋白基因表达，支持跨越两个数量级的细胞锌配额。因此，单个锌传感器可以促进皮摩尔到微摩尔锌浓度的增长，并有利于储存这种宝贵的资源。由此产生的在超低和过量锌条件下生长良好的能力，以及总体较低的锌需求量，可能有助于聚球藻在全球海洋中的广泛生态分布。