Mining genomes of marine cyanobacteria for elements of zinc homeostasis.
Mining genomes of marine cyanobacteria for elements of zinc homeostasis.
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DOI：
10.3389/fmicb.2012.00142
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发表时间：
2012
影响因子：
5.2
通讯作者：
Blindauer CA
中科院分区：
文献类型：
--
作者：
Barnett JP;Millard A;Ksibe AZ;Scanlan DJ;Schmid R;Blindauer CA
锌是大多数生物体公认的必需元素，对数百种酶和数千种调节蛋白的正常功能不可或缺。在包括蓝藻在内的水生光合自养生物中，尽管有证据表明至少一些碳酸酐酶具有兼性（即能够在体内获取并与不同的金属辅因子如Co²⁺和Cd²⁺一起发挥作用），但锌被认为是碳酸酐酶和碱性磷酸酶所必需的。鉴于海洋浮游植物在全球的重要性，海洋中锌的可利用性可能对碳和磷循环都有影响。海水中锌的浓度变化幅度达几个数量级，在开阔海洋中呈现出类似营养物的分布特征。大多数关于蓝藻对锌处理的研究都集中在淡水菌株和锌毒性方面；关于海洋菌株和锌限制的信息则少得多。在淡水物种集胞藻属PCC 7942和聚球藻属PCC 6803中，已经对几种锌稳态系统进行了表征，但对于海洋物种的锌需求或锌处理知之甚少。比较金属基因组学已经开始不仅探索假定的锌蛋白质组，还探索预计参与锌稳态的特定蛋白质家族，包括过量和限制的传感器（SmtB及其同源物以及Zur）、摄取系统（ZnuABC）、假定的细胞内锌伴侣蛋白（COG0523）和金属硫蛋白（BmtA）以及外排泵（ZiaA及其同源物）。
Zinc is a recognized essential element for the majority of organisms, and is indispensable for the correct function of hundreds of enzymes and thousands of regulatory proteins. In aquatic photoautotrophs including cyanobacteria, zinc is thought to be required for carbonic anhydrase and alkaline phosphatase, although there is evidence that at least some carbonic anhydrases can be cambialistic, i.e., are able to acquire in vivo and function with different metal cofactors such as Co2+ and Cd2+. Given the global importance of marine phytoplankton, zinc availability in the oceans is likely to have an impact on both carbon and phosphorus cycles. Zinc concentrations in seawater vary over several orders of magnitude, and in the open oceans adopt a nutrient-like profile. Most studies on zinc handling by cyanobacteria have focused on freshwater strains and zinc toxicity; much less information is available on marine strains and zinc limitation. Several systems for zinc homeostasis have been characterized in the freshwater species Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803, but little is known about zinc requirements or zinc handling by marine species. Comparative metallo-genomics has begun to explore not only the putative zinc proteome, but also specific protein families predicted to have an involvement in zinc homeostasis, including sensors for excess and limitation (SmtB and its homologs as well as Zur), uptake systems (ZnuABC), putative intracellular zinc chaperones (COG0523) and metallothioneins (BmtA), and efflux pumps (ZiaA and its homologs).
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影响因子：
3
作者：
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通讯作者：
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作者：
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