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Proteins

 

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Overview
Proteins run our show. Muscles, organs, hair, bone, and skin either contain or are made of proteins. They are a major component in all of our cells. Enzymes that run the chemical reactions in our bodies are proteins. Proteins help us move, send messages (hormones and nerve receptors), fight off disease (antibodies), and transport other molecules and atoms around our bodies. A protein is a molecule that consists of a chain of amino acids. There are 20 different amino acids to choose from, and the genetic information in our DNA determines how they're put together. A single protein consists of hundreds of amino acids, all folding into a structure with a specific shape. What job a protein does in the body is determined by its structure (its conformation) and the way it moves (its dynamics). Hemoglobin, for example, is an important red blood cell protein that delivers oxygen to tissues and hauls carbon dioxide to the lungs for removal. In the lungs, oxygen binds to the iron atoms inside a hemoglobin molecule and any attached carbon dioxide is released. In the tissues, the molecules of oxygen are released and more carbon dioxide is picked up. As illustrated in the video segment, it is the motions of parts of the hemoglobin molecule that makes this binding and release action work. Scientists can investigate these motions or dynamics as well as the protein's structure using a technique called NMR (nuclear magnetic resonance) spectroscopy. The nuclei of some atoms are like little magnets; they align within a magnetic field. If disturbed by a very quick blast of radio waves, this alignment is disrupted and these little magnets gradually relax back into alignment with the field. Researchers can interpret this NMR relaxation to get very detailed information about molecular motion and how proteins do their many different tasks in the body.

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