Structure of Nucleic Acid3

Structure of Nucleic Acid3 - the bonds between the...

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Structure of Nucleic Acids DNA is a Right-Handed Helix Each strand of DNA wraps around the other in a right-handed configuration. In other words, the helix spirals upwards to the right. One can test the handedness" of a helix using the right hand rule. If you extend your right hand with thumb pointing up and imagine you are grasping a DNA double helix, as you trace upwards around the helix with your fingers, your hand is moving up. In a left-handed helix, in order to have your hand move upwards with your thumb pointing up, you would need to use your left hand. DNA is always found in the right-handed configuration. The Major and Minor Grooves As a result of the double helical nature of DNA, the molecule has two asymmetric grooves. One groove is smaller than the other. This asymmetry is a result of the geometrical configuration of
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Unformatted text preview: the bonds between the phosphate, sugar, and base groups that forces the base groups to attach at 120 degree angles instead of 180 degrees. The larger groove is called the major groove while the smaller one is called the minor groove. Since the major and minor grooves expose the edges of the bases, the grooves can be used to tell the base sequence of a specific DNA molecule. The possibility for such recognition is critical, since proteins must be able to recognize specific DNA sequences on which to bind in order for the proper functions of the body and cell to be carried out. As you might expect, the major groove is more information rich than the minor groove. This fact makes the minor groove less ideal for protein binding....
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