September 8 - polypeptide chain o Stabilized by noncovalent...

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September 8, 2010 Lecture 3 Midterm October 21, 2010 Review from Last Class Polypeptide: A linear strand of amino acids joined together by peptide bonds Primary structure: the sequence of amino acids in a polypeptide A protein can have one, or several polypeptides in it Peptide bond: bond formed between amino group of one amino acid and the carboxylic acid group of another Amino end: (N-terminus) H3N+ Carboxyl end: (C-terminus) O- C=O, O has a slightly negative charge N-H, H has a slightly positive charge o Combined these two small charges allows for hydrogen bonding between polypeptides Secondary structure: folding or conformation localized regions of a
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Unformatted text preview: polypeptide chain o Stabilized by noncovalent interactions, specifically hydrogen bonds • Stretches with no noncovalent interactions random coil o Have no secondary structure o Can be rigid or flexible • Alpha Helix o The interaction between the hydrogens with a positive charge and the oxygens with a negative charge stabilizes the stretch of polypeptide into a helix o All R groups are arranged radially pointing outward o Each amino acid is involved in 2 hydrogen bonds o About 3.5 residues exist in each turn of the alpha helix o...
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This note was uploaded on 10/23/2010 for the course BIOL BIOL 200 taught by Professor Bureau during the Fall '09 term at McGill.

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