2006 - Asp residue would be more disruptive. (c) Glu. The...

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Mandatory Homework #5, Key Fall 2006 CHEM 4711 1. A polypeptide synthesized in a living cell has a sequence that has been optimized by natural selection so that it folds properly (with hydrophobic residues on the inside and polar residues on the outside). The random sequence of the synthetic peptide cannot direct a coherent folding process, so hydrophobic side chins on different molecules aggregate, causing the polypeptide to precipitate from solution. 2. (a) Phe. Ala and Phe are both hydrophobic, but Phe is much larger and might not fit as well in Val’s place. (b) Asp. Replacing a positively charged Lys residue with an oppositely charged
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Unformatted text preview: Asp residue would be more disruptive. (c) Glu. The amide-containing Asn would be a better substitute for Gln than the acidic Glu. (d) His. Pro’s constrained geometry is best approximated by Gly, which lacks a side chain rather than a residue with a bulkier side chain such as His. 3. Yes, although such irregularity, while often called “random coil” is not truly random, as the irregular structure would be fixed into a discrete native state. 4. Hydrophobic effects, van der Waals and hydrogen bonds are destroyed during denaturation. Covalent crosslinks (Voet & Voet!) are retained....
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This note was uploaded on 11/12/2010 for the course CHEN 3320 at Colorado.

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