RUI: Determining Non-Symbiotic Hemoglobin Function in Plants

Drake University, Des Moines IA

Investigators

Abstract

With this award, the Chemistry of Life Processes Program in the Chemistry Division will be funding Dr. Sturms from Drake University to investigate the ancestral function of non-oxygen transport hemoglobins in early forms of plant life. While most people are familiar with hemoglobin's role in transporting oxygen in blood, scientists have increasingly recognized that oxygen transport may not be the original function of these important proteins. Understanding the true ancestral purpose of hemoglobins will help us to understand basic rules about how proteins developed their specialized functions over millions of years. This research will focus on hemoglobin proteins found in bryophytes, which are simple plants like mosses and liverworts that still exist today but represent some of the earliest forms of plant life on Earth. By studying hemoglobins from early land plants, this research will uncover how these biological molecules support life processes, with potential applications for understanding metabolic disorders and developing new biotechnologies. The project will provide hands-on research training for 6-8 undergraduate students, preparing them for careers in science and technology. Additionally, 2-3 high school teachers will receive laboratory training and professional development through collaboration with Iowa State University's Research Experience for Teachers Program, enabling them to bring cutting-edge scientific knowledge back to their classrooms and inspire the next generation of scientists. This research project will be carried out to determine whether bryophyte hemoglobins function in oxygen transport or instead serve alternative metabolic roles, particularly in nitrogen metabolism under low-oxygen conditions. The study will examine hemoglobin proteins from three bryophyte species: Physcomitrella patens, Marchantia polymorpha, and Anthoceros punctatus. The research will address three specific objectives through detailed protein characterization studies. First, this study will determine if bryophyte hemoglobins display heme coordination and ligand binding characteristics consistent with oxygen transport by measuring visible absorbance spectra and monitoring ligand binding kinetics. Second, enzyme kinetic measurements will evaluate whether these hemoglobins exhibit reaction rates with nitrogen-containing molecules that would support their involvement in metabolic pathways, including nitrite reduction, hydroxylamine reduction, and nitric oxide dioxygenase activity. Third, structural characterization of bryophyte hemoglobins will be conducted using protein crystallography and infrared spectroscopic techniques to understand how structure relates to function. Results from these studies will advance understanding of the evolutionary origins of hemoglobin function and provide new insights into the "Rules of Life" that govern protein structure-function relationships in biological systems. 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.