Structure of Peptide Bond

Structure of Peptide Bond - and thus defines the amino- or...

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Structure of Peptide Bond Electrons are shared by the O,C, & N atoms in such a way the bond has a stiffness which resists rotation. As a result, each peptide bond lies in a flat plane ( Fig. 3 ). Rotations must occur at the alpha carbon around the Phi and Psi bonds ( Fig. 4 ). Peptides and Polypeptides A peptide consisits of a small number of amino acids connected by peptide bonds. These form an articulated chain of flat plates ( Fig. 4 ). A longer chain of amino acids joined in this manner is called a polypeptide. We can define the direction of a polypeptide chain according to the orientation of the peptide bonds. The amino acid at one end of the chain must have a free NH2 group
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Unformatted text preview: and thus defines the amino- or N terminal end ( Fig. 4 ). The amino acid at the other end must have a free COOH group and thus defines the carboxy- or C terminal end ( Fig. 4 ). Protein sequences are conventionally written from N-terminus (at the left) to C-terminus (at the right). The peptide bonds form a zig-zag backbone, from which the side-groups (denoted R) protrude ( Fig. 5 ). The R group is different for each amino acid and determines the nature of its contribution to the overall protein structure....
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