Heterotrimeric G proteins are a class of signaling molecules found throughout the animal kingdom with an extremely high degree of complexity and regulation. These molecules have just recently been discovered in plants as well, albeit with an incredible lack of intricacies. Elsewhere, it has been reported that neuroglobin, a newly discovered hexacoordinate hemoglobin, interacts with the Gα subunit in animal systems. Plants as well have many hexacoordinate hemoglobins, termed nonsymbiotic hemoglobins, of unknown function. Because of the similarity between plant and animal Gα subunits, the assumption that these plant nonsymbiotic hemoglobins may play a similar role with plant Gα subunits was investigated. Using purified atGPA1 from Arabidopsis and Gα[subscript il] from rat, the binding to multiple hemoglobins was measured with surface plasmon resonance. Both Gα subunits interact similarly with hemoglobins from both animal and plant kingdoms; however, animal hemoglobins exhibit a strong nucleotide dependence while plant hemoglobins do not. Mutations near the E7L histidine also play a role in binding. These novel findings lay the groundwork for future study on Gα and hemoglobin interactions.