One important part of our diet is iron. Iron is a metal that is very important in helping us get energy from our foods. Without adequate amounts of iron we will become very tired and eventually very sick. That is because iron is involved in the end stages of energy production. For example when our bodies breakdown sugar we end up giving off lactic acid, carbon dioxide, water, and storable energy in the form of ATP (adenine triphosphate). When needed the ATP will breakdown to ADP (adenine diphosphate) releasing this stored energy. To get the most ATP out of each sugar molecule we use iron containing molecules called cytochromes. Without these cytochromes our bodies would soon lack the energy needed to survive.
Iron also transports oxygen to the cells of our bodies via our red blood cells when attached to a protein called hemoglobin. We need to live in an oxygen environment because oxygen is also involved in the end stages of ATP production. Oxygen accepts the leftover electrons from sugar breakdown and with a couple of hydrogen atoms makes water. Water is a byproduct of sugar breakdown and energy generation. Our bodies consider iron such a precious metal that it produces iron binding proteins that hold on to any extra iron that maybe in our bodies.
We are not the only ones that need iron to survive. Most bacteria also need iron to live. They, like us, use iron to help in generating ATP. Bacteria have developed very elaborate means to get iron from the environment so they can survive. In fact the iron binding proteins in our bodies are important in preventing many bacterial illnesses. If all the available iron is bound to these proteins many bacteria simply die of ATP starvation. To get around this particular defense mechanism most bacteria that infect humans produce compounds that grab the iron from our iron binding proteins.
The Lyme disease bacterium has developed another way around this problem. It does not need iron at all. Researchers at the University of Georgia have discovered that the Lyme disease bacterium, Borrelia burgdorferi, only has 5 molecules of iron per cell. If given too much iron it will die. It enjoys iron-free environments. Instead of using iron to generate ATP it uses manganese. Without the need for iron this particular bacterium doesn’t have to fight with our iron binding proteins to survive and can live quite well in our bodies for long periods of time.
This ability to live without iron is very rare. Only one other bacterium, Lactobacillus planatarum, has been identified that doesn’t need iron to live. This knowledge may help Lyme disease researchers better understand how this organism causes disease and may also help in the design of antibacterial compounds that could kill these unique microorganisms. Life can be very interesting. You think you have it all figured out and POW some microbe or another does things just a little bit differently