This makes it expensive to make a protein maybe 300

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Unformatted text preview: s expensive to dehydrate with all the water that’s around) Proteins are also formed by condensation and broken down by hydrolysis. This makes it expensive to make a protein (maybe 300 amino acids). But proteins are much more expensive to make than you’d think, if hydration were the only problem ---- wonder why? Protein = a specific polymer of amino acids COO ­ end And popping out of that “backbone” is also a simple repea5ng structure of H’ s and O’ s (we’ re ignoring the R ­groups)… NH3+ end HO HO HO HO + H NCCNCCNCCNCCNCCNCCNCCNCCO- H HO HO HO HO This backbone structure by itself helps the protein fold into “ secondary structures” ­ forming flat planes, or rigid cylinders. These planes and cylinders are stabilized by hydrogen bonds between the repea5ng N ­H and C=O groups in the backbone. The “backbone” is a very simple repea5ng structure… NCCNCCNCC Protein sequences are always wri[en star5ng with the N terminus. The R groups influence whether the protein will fold into a cylinder or sheet (or “random” loop), but the hydrogen bonds within the backbone itself hold these secondary structures together. What’s a hydrogen bond? • A hydrogen bond is sort of a baby polar bond, and sort of a way for two atoms to share a single H. For example: View Youtube v ideo, if we’re lucky Hydrogen bonds are weak interac5ons ­ not at all like covalent bonds. But they can really add up… The N ­H and carbonyl (C=O) groups in a protein can H bond to each other to produce either flat sheets or rigid rods. Although any one H bond is quite weak, many bonds can collaborate to form a stable structure. HO HO HO Figure 3.6 The Four Levels of Protein Structure HO + H NCCNCCNCCNCCNCCNCCNCCNCC H HO HO HO HO OH OH OH OH -OCCNCCNCCNCCNCCNCCNCCNCCNCCO OH OH OH OH O Alpha helix The serpen5ne winding shown here will...
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This note was uploaded on 05/17/2013 for the course BIS 100 taught by Professor Charles during the Winter '11 term at UC Davis.

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