BIS 102 MT2 Spring 07

BIS 102 MT2 Spring 07 - lof2 BIS 102 Name ézj Spring 2007...

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Unformatted text preview: lof2 BIS 102 Name ézj Spring, 2007 MWF Last First K. Hilt Second Midterm Score (100): Amino Acid R-group pKa’s: D (3.9), E (4.2); H (6.0); K (10.5), R (12.5); C (8.3); Y (10.1) Determine if the following statements are “true” or “false”. Each statement is worth 5 points — 1 point for putting in the correct “T” or “F”; the other 4 points for defending your answer. If a statement is “false” for more than one reason, then explain all of the false aspects of the statement. 1. F Dr. Anfinsen’s experiment with refolding denatured RNaseA, gave the best results when 02(g) was bubbled in first, followed by removal of urea using ion exchange chromatography. remove We uxto. Jab/5+. uwvj +2. 2. F Deoxy Hb has about 13 salt bridges. If a mutant Hb consisted of three oc-subunits and three B— subunits, and delivered oxygen in a way similar to normal Hb, we would expect that the mutant Hb would have about 15 salt bridges in its structure. (Show a calculation if you disagree with the statement). \3 *I‘ x q, *1 M is a. \p *7- ————’-‘-’" =- x 1: 14.5 '= 20 ) I e 2 ‘ x a \L W m up...“ \ L‘ in b 02 “aw Laura—M— 06. safli 1’“ 3. 1: Reverse turns are stabilized by a single H-bond between the R-groups of the first and fourth amino acid residues that comprise the turn. i: 0):? ‘5:- flstM WW1 1‘, 3+ qfix fi my: 1 I 4 K ~ W ‘ 4. F The pKa of a glutamic acid residue in a protein increases substantially when an arginine side chain in the same protein comes into close proximity. :1 E MhW+LH++° W E M @W‘M“ 511mg,“ 10ml. wxw g+ +1 5. l: The peptide sequence HHHHHHHHHH would not form an a-helix at pH 11, but might form an oc-helix at pH 1. N. (H [1, Ha. HAL: aka-Ly. If. H 1144. hp” 0AM , 312+ mi Quinn M outsdblgfl Hummer, 02+ (H1, fl~c 5119—2 chm/1. ~m+l,+z M WI” rw’f’ {arm m ¢~W~ 6. F Protein Z is a dimer. There is no type of protein 2° structure that could exist between the surfaces of the two subunits. {3 _ f I $0.121 51.44:!“ 901414! . “l 7. F Extraction of the DNP-a.a. in the Sanger method with diethylether will work if the extraction is d ' 6NNOH° tad f6NH l. *2” « - 5..:;‘*..:..... 2. “3...... m6 m 411W»... Wt, K had“, ‘ m A}.- +oym§wu€ DAM—4.4. NM rfi Hal. 61W “0&4- WI‘H 24W ik‘i‘b Tat em M47”. 8. 15‘ The peptide sequence SEGEFAMSI will always be cut by chymotrypsin into two separate +1 pieces. . 5 ‘ " . \ SW A Adm. 56W an Hm “2&1 viz. KL 1:" bui- vxu‘t {4- M :5 0L JJSulgl‘éQngM "H‘L +UJD QCS. 9. E The interior packing ratio of a typical globular protein is similar to that of an oil droplet, with about 50% of the interior volume being open space. + L m rd‘io if; a» 4‘04wa 1‘5 0‘75- I . W of; cm oil Mid [5 0.70, +2.. 20f2 Biological Sciences 102 Name % 10. 1" One function of the protein portion of Mb is to prexgrlt oxidation of the heme iron. {-1, 5Wiw’eflj (W W' a;' I‘m 5miugok. 11. F A peptide has an N-terminal lysine and an internal lysine. Dr. Sanger could have differentiated between these two lysines in the following ways: $6 derivatized lysines would have been e in the ether layer of a 6 N HCl/ether extraction; bptlj would hav en equally yellow; and detecting each on a TLC plate would be @531 using ninhydrin. 1‘ mi in M (W am law ntr fissure, N'“"*‘- K “We? let Mar M W 39¢ H ~ WW + bis .— D N? — K 12. F In the protein sequenator, the machine that uses the Edman chemistry, cleavage of the N- terminal derivatized amino acid residue is catalyzed initially using am lSH-Iéliat room temperature. Eventually, the PTH-a.a. is separated and identified using a 3W oqan cglg-nm. *\ y W Malachit- ’, "k2. +yi-‘E’\wu~raa.a::2. “:3. 13. F Of the various negative heterotropic allosteric effectors of Hb, H)r is the most important. + 7. t [5 £84 M :W; “W at. Bfé an» 02 5%”? WV” ‘ “Ac-5" 75 V442, similar +0 Hi9 ‘1 +L 14. E Hemoglobin has three different histidine residues that participate, directly or indirectly, in the transfer of 02 from the lungs to the tissues. We would rank these histidines, in order of importance, from hi to low, as: distal > roximal > C-terminal H of the -subunits. g gh Ké .H \. V‘Ufimfiufl, = mBP’\- ;%N*ud. cwkwfl 4’.» Cowmvmzcofi‘wu, +\ Ha. ‘M:Wbtdo.fim.w&wd~mw, +13. c—wan'l 2 am wstm W Ptokw‘, ‘— H3... I’M 15. E A single bond rotation takes about 10'13 sec at room temperature. Dr. Levinthal showed mewi-md' that a peptide containing 100 amino acid residues would fold in about (100)(10'13 sec) = 10'11 sec. in viva. +2— _ 3 +7-— [L/0)’wm+¢wmah\0“;l[lo‘ : [077 m ' ! 16. F A mutation in the N—terminal amino acid residue of the oc-subunits of H ould seriously affect both the acid and C02 portions of the Bohr effect. I + 7- . A_ Wagm fl“, ‘TIML N'Mm‘naac IS resQwsibla Pm H“ “We wz W m m “data/Ma. +7. 17. 'T' Carbon monoxide would be labeled a “positive heterotropic allosteric effector” of Hb. ‘i L T I\ d. 0 brad“. +1 - W W + a 2- 18. E Binding of CI' in Hb occurs between the two'K-subunits, involving a histidife side chain on each subunit. at. “330%. ’r 2 + 7— 19. T Mutation of the proximal histidines in Hb to valines would cause a serious change in the 02 binding curve of Hb. mschm;wlajz\o€eW¥WMaaWbMfim H I I + . . Fe“. \leim affix W cm” (Lo 1444 , (4:444! M WWW, 20. F The overall strategy for sequencing a protein today is the same as that originally used by Dr. Sanger. \ ' ‘ 14w l \ “fl/m us a. simlam'i'? we. 5+.“ low-V4. W m MW,*J-vt€-a we. 47} +9 Quit W Vale/w» «wit é”: Me. 4,900 4.4. MM IN; Sura‘a‘lo‘t {w HM— ,woJ-oon 52M ...
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This note was uploaded on 04/03/2012 for the course BIS 102 taught by Professor Hilt during the Spring '08 term at UC Davis.

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BIS 102 MT2 Spring 07 - lof2 BIS 102 Name ézj Spring 2007...

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