Parsing the biogeochemistry of marine carbonic anhydrases

尽管在大气和海水中都发现了二氧化碳，但它与水的反应并不迅速。这给海洋生物带来了一个问题，它们需要等待二氧化碳与水反应后才能将其用于光合作用。因此，生物体使用一种酶来极大地加速这一反应。这种被称为碳酸酐酶(CA)的酶非常有用，在整个生命树上都能找到它。然而，碳酸酐酶在二氧化碳循环中的作用一直很难衡量。在这个项目中，来自伍兹霍尔海洋研究所的一组研究人员将使用仪器技术和实验室实验相结合的方法来研究不同类型的CA在海洋生物中的作用。该团队将确定不同类型的CA及其固有的催化速率。然后，研究小组将确定这些酶中存在的金属辅因子，这是酶功能的关键。这项工作将加深我们对海洋浮游植物二氧化碳循环的生化基础的理解，并将为地球上最普遍、速度最快的酶之一提供关键的见解。该团队将与汉普顿大学的因杜·夏尔马教授和她的学生合作，该大学刚刚启动了一个新的海洋科学专业项目。团队成员将访问汉普顿大学，参加一个关于海洋学职业的研讨会。在第二年，夏尔马教授和她的学生将陪同团队前往百慕大-大西洋时间序列进行研究考察，并将帮助设计一项采样活动，重点关注夏尔马教授和研究人员的共同研究兴趣。碳酸酐酶(CA)是一种普遍存在的酶，参与海洋环境中几乎所有的碳转化。每一个CA在其活性部位都使用一个金属辅因子，而CA的表达与表层海洋对锌、钴等痕量金属的吸收和利用有关。我们开始了解到生物体表达许多不同形式的CA，所有这些CA都具有不同的生理作用，表现出独特的催化速率，并且可以在酶活性部位使用不同的金属辅因子。在这项研究中，该团队将利用这种酶的多样性来研究海洋硅藻中的碳酸氢酶动力学。通过将基于同位素的酶活性分析与定量蛋白质组学相结合，他们将记录多种CA亚型的内在动力学。此外，他们将确定与最丰富的CA相关的金属辅因，从而在酶活性和痕量金属利用之间提供直接联系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Although carbon dioxide (CO2) is found both in the atmosphere and in sea water, it does not react quickly with water. This presents a problem for marine organisms that need to wait for CO2 to react with water before using it for photosynthesis. Therefore, organisms use an enzyme to greatly speed up this reaction. The enzyme, known as carbonic anhydrase (CA), is so useful that it is found across the entire tree of life. However, the role of carbonic anhydrase in the CO2 cycle has been hard to measure. In this project, a team of investigators from the Woods Hole Oceanographic Institution will use a combination of instrument techniques and laboratory experiments to investigate the role of different types of CA in marine organisms. The team will identify the different types of CA and their inherent catalytic rates. The team will then identify the metal cofactors present in these enzymes, which are key for enzyme function. This work will deepen our understanding of the biochemical basis for carbon dioxide cycling in marine phytoplankton, and will provide key insights into one of the most ubiquitous and fastest enzymes on the planet. The team will collaborate with Professor Indu Sharma and her students from Hampton University which has just launched a new marine science major program. Team members will visit Hampton University for a workshop on careers in oceanography. In Year 2, Professor Sharma and her students will accompany the team on a research expedition to the Bermuda-Atlantic Time Series and will help design a sampling campaign focused on the shared research interests of Professor Sharma and the investigators. Carbonic anhydrases (CAs) are ubiquitous enzymes involved in almost every carbon transformation in the marine environment. Every CA uses a metal cofactor in its active site, and the expression of CAs is tied to the uptake and utilization of trace metals such as zinc and cobalt in the surface ocean. We are starting to understand that organisms express many different forms of CA, all of which serve distinct physiological roles; exhibit unique catalytic rates; and can use different metal cofactors at the enzyme active site. In this proposal, the team will exploit this enzymatic diversity to investigate carbonic anhydrase kinetics in marine diatoms. By combining an isotope-based enzyme activity assay with quantitative proteomics, they will document the inherent kinetics of multiple CA isoforms. In addition, they will identify the metal cofactors associated with the most abundant CAs, therefore providing a direct linkage between enzyme activity and trace metal utilization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.