Neuroglobin Gone Wild

Abstract

Neuroglobin (Ngb) has an important role in maintaining homeostasis through processes such as the detoxification of nitrogen, the storage/transport of oxygen, and the protection of neurons at risk of unwanted apoptosis. One of the fascinating differences between neuroglobin and all the other globins is that it has a hexa‐coordinated heme group. In neuroglobin, all six coordination positions are bound, creating a slightly different mechanism for when oxygen has to bind. Protein concentration of Ngb is tissue dependent. In retinal cells, where there is a high demand for oxygen, Ngb concentrations can be up to 100 times greater than in neurons. Levels of expression determine the role Ngb is going to have, such as a regulator of metabolic functions in the hypothalamus or involvement in the signaling pathways in neuronal development. Oxidative stress may lead to disruption of the mitochondria causing the release of cytochrome c, the beginning of apoptosis. In addition to its role in oxygen delivery, Ngb is a neuroprotective protein released by astrocytes, which reside between the neurons, that detect changes in the environment. It is believed that Ngb may slow and possibly stop cell death. Ferrous Ngb performs a redox reaction with ferric cytochrome c while binding with amino acids glu 60,87 on Ngb and the cytochrome c amino acids lys 72,25. Ngb binds to the same site on cytochrome c where the cytochrome would bind with other apoptotic molecules to form an apoptosome that would activate executioner caspases. Research has been done to link intrinsic characteristics with conditions presented by the cell in stress, such as acidosis or hypoxia have led to identifying a probably role of Ngb as a neural protector. Cell death is associated with mitochondrial dysfunction and is common in neurological disorders. Degenerative brain disorders ‐ amyotrophic lateral sclerosis, Alzheimer's, Huntington's, and Parkinson's disease, among others affect more than 45 million people worldwide. An understanding of these actions may provide a basis for new research and drugs to inhibit excessive neuronal cell death. The El Capitan High School CBM MAPS Team used 3‐D modeling and printing technology to examine structure‐function relationships of neuroglobin.