Collaborative Research: Cellular, Ecological, and Biogeochemical Impacts of a Novel Blue Copper Ferritin

J. Craig Venter Institute, Inc., La Jolla CA

Investigators

Abstract

Phytoplankton require iron to grow and to produce the organic matter that fuels marine ecosystems, helping to draw down carbon from the atmosphere. But the ability to understand how iron availability in the ocean impacts phytoplankton productivity and carbon drawdown is constrained by a limited understanding of the reservoirs of iron in the marine environment. This research into phytoplankton iron storage mechanisms provides new insights into the production of biogenic molecules by phytoplankton which help maintain iron in the well-lit upper layers of the ocean. The study characterizes the mechanism of a novel protein – a copper-based ferritin – and explores how this environmentally abundant class of proteins may provide an ecological advantage to some marine phytoplankton and help explain the maintenance of dissolved iron in the water column. It advances the understanding of how iron limitation affects marine ecosystems and their capacity to draw down carbon. Furthermore, the project supports the development of a K-8 educational module using hands-on tidepool chemistry and ecology to teach children broader concepts in biogeochemical cycling. This educational effort targets 600 seventh-grade students from a middle school serving underserved populations in Southeastern San Diego. The educational module is to be made broadly available via marine science educational websites. This project is guided by mechanistic, phenotypic, and biogeochemical hypotheses. Recent state-of-the-art advances in metalloproteomics are leveraged to understand the electrochemical loading and unloading of iron in novel blue copper ferritins, both in-vivo and in-vitro, using the model diatom Phaeodactylum tricornutum. Reverse genetics techniques are used to characterize how blue copper ferritins contribute to ecological advantage in iron-limited oceans. Because these blue copper ferritins, new to science, are self-assembling, thermostable, electrochemically-controlled cargo delivery proteins, their description can be of interest to nano- and bio-engineers. 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.