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1. ATP synthesis How much energy is stored in bringing together a phosphate and ADP moiety from infinite separation to bonding distance in solution? Assume the contribution from the chemical reaction is negligible and water has a dielectric of 80. Furthermore, we assume the charges are centered on the phosphor atoms. The phosphor to phosphor distance is 0.26 nm. 2. Proton-motive force How much energy is required to move one proton from one side to the other side of a membrane of about 5 nm thickness, given that there is a potential difference of 50 mV over the membrane? Is this enough to create one ATP molecule? If not, how much protons have to be pumped over the membrane in order to build one ATP molecule? 3. Photosynthesis How many photons need to be absorbed by the bacterial reaction center in Rhodobacter Sphaeroides in order to create an ATP molecule? The reaction center has an absorption maximum at 800 nm. What is the efficiency of the photosynthesis process? 1/4 4. NMR spectroscopy In the figure is shown a one-dimensional H-NMR spectrum of ethanol (CH3-CH2OH). The peak at 0 ppm is the TMS reference peak. Type of Proton Cyclopropane Primary Secondary Tertiary Vinylic Acetylenic Aromatic Benzylic Allylic Fluorides Chlorides Bromides Iodides Alcohols Ethers Esters Esters Acids Carbonyl Compounds Aldehydic Hydroxylic Phenolic Enolic Carboxylic Amino Structure C3H6 R-CH3 R2-CH2 R3-C-H C=C-H triple bond,CC-H Ar-H Ar-C-H C=C-CH3 H-C-F H-C-Cl H-C-Br H-C-I H-C-OH H-C-OR RCOO-C-H H-C-COOR H-C-COOH Chemical Shift, ppm 0.2 0.9 1.3 1.5 4.6-5.9 2-3 6-8.5 2.2-3 1.7 4-4.5 3-4 2.5-4 2-4 3.4-4 3.3-4 3.7-4.1 2-2.2 2-2.6 H-C-C=O 2-2.7 R-(H-)C=O R-C-OH Ar-OH C=C-OH RCOOH RNH2 9-10 1-5.5 4-12 15-17 10.5-12 1-5 2/4 Use the table to assign the peaks to specific protons. Predict the spectra of the following organic molecules: • • • • • • Methane (CH4) (supposing we can solve this..) Ethane (CH3-CH3) Propanol (CH3-CH2-CH2-OH) Isopropanol ((CH3)2-CHOH) Pentane (CH3-(CH2)-CH3) Glycine (NH2-CH2-COOH) 5. Protein NMR A two-dimensional 1H-15N correlation spectrum has been obtained by transferring magnetization from amide proton to amide nitrogen to improve signal-to-noise ratio. Subsequently the frequency of nitrogen (fN) has been collected and thereafter magnetization has been transferred back to amide proton for monitoring its frequency (fH). Frequencies are given relative to a reference compound. This type of measurement is called Heteronuclear Spin Quantum Coherence (HSQC). Below is shown a typical HSQC spectrum. What do we learn about the protein structure from this spectrum? Are there multiple conformations? 3/4 Why is there no proline in the spectrum? Why does the first residue not give a signal? Are there any amino acids that give characteristic resonance? How would the spectrum look like if acquired in the field of twice as strong? What might the horizontal lines in the spectrum mean? Why are there very small peaks just above these cross peaks at upper right part of the spectrum? 6. Projects for next week Prepare an oral presentation of about 5-10 minutes on one of the following topics: • • • • • Levinthal paradox Enzymatic mechanism of chemotrypsin, lysozym, or papain Computer aided drug design Composition of hair Hydrophobic effect 4/4