Basics of Protein Structure: Difference between revisions
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== Levels of Protein Structure == | == Levels of Protein Structure == | ||
There are [[Four levels of protein structure|four different levels of protein structure]]. The <scene name='60/604417/Ins_bead_backbone_labels/1'>primary structure</scene> is the amino acid sequence. The amino acids are connected by an amide bond, made from the amino group (NH2) of one amino acid, and the carboxylic acid (C=O) from another amino acid. The amino acids are linked in a repeating pattern. The backbone of the protein is the repeating N-C-C=O pattern, with the side chains projecting out from the backbone. The end with the free -NH2 group is called the N terminus, while the end with a free carboxylic acid is called the C terminus. The sequence of amino acids is written from the N terminus to the C terminus. | There are [[Four levels of protein structure|four different levels of protein structure]]. The <scene name='60/604417/Ins_bead_backbone_labels/1'>primary structure</scene> is the amino acid sequence. The amino acids are connected by an amide bond, made from the amino group (NH2) of one amino acid, and the carboxylic acid (C=O) from another amino acid. The amino acids are linked in a repeating pattern. The [[Backbone representations|backbone]] of the protein is the repeating N-C-C=O pattern, with the side chains projecting out from the backbone. The end with the free -NH2 group is called the Amino or N terminus, while the end with a free carboxylic acid is called the C terminus. The sequence of amino acids is written and numbered from the N terminus (where protein synthesis begins) to the C terminus (where amino acids are added during protein synthesis). | ||
The second level of structure is called secondary structure, and is the | The second level of structure is called secondary structure, and is the shapes (conformations) formed by short sequences of amino acids. This level of structure is stabilized by <scene name='57/575866/H_bond_a_helix/3'>hydrogen bonds</scene> along the <scene name='57/575866/Backbone/2'>backbone</scene>. (More about [[hydrogen bonds]].) The two most common shapes are [[Helices in Proteins|alpha helices]] and [[Sheets in Proteins|beta strands]]. These are favored simply because [[Tutorial:Ramachandran principle and phi psi angles|two atoms cannot occupy the same space]] (steric collisions). | ||
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* [[Intrinsically Disordered Protein]] | * [[Intrinsically Disordered Protein]] | ||
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