10 - LECTURE 10 ANNOUNCEMENTS 1 QUIZ 2A 23.3 2B 24.5 2C 23.9 2 NO LETTER GRADES AT THIS TIME A VERY ROUGH IDEA OF WHERE YOU STAND DIVIDE RAW SCORE

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Unformatted text preview: LECTURE 10 ANNOUNCEMENTS 1. QUIZ 2A 23.3 2B 24.5 2C 23.9 2. NO LETTER GRADES AT THIS TIME. A VERY ROUGH IDEA OF WHERE YOU STAND: DIVIDE RAW SCORE BY MEAN NORMALIZED SCORE ("NS"); MID-RANGE FOR GRADE OF A, NS = 1.2; MID-RANGE FOR B+, NS = 1.0; MID-RANGE FOR GRADE OF C, NS = 0.8. THIS IS A ROUGH GUIDE . 3. THREE WEDNESDAYS WHEN THERE WILL NOT BE A QUIZ: 10/13 (DAY OF RETURN FROM FALL BREAK) 10/20 (DAY BEFORE THE MIDTERM EXAM) 11/24 (DAY WHEN THANKSGIVING RECESS BEGINS) 4. MEET TODAY WITH ANY INTERESTED TRANSFER STUDENTS TO DISCUSS "HOW TO SUCCEED AT THIS PLACE!", 2:55-4 PM IN B108 COMSTOCK. WEDNESDAY'S LECTURE: THERMODYNAMIC TREATMENT OF PROTEIN FOLDING PROTEINS CAN RENATURE ∴ ALL INFO FOR FOLD STRUCTURE IS IN AA SEQUENCE TODAY: WHY DO SOME PROTEINS NEED HELP TO FOLD? MOTION INSIDE PROTEINS! "PATHWAY" OF PROTEIN FOLDING? BUT THAT PROTEINS FOLD FAST, IN SECONDS-TO-MINUTES, IS NOT UNDERSTOOD REAL WORLD: 2 ENZYMES SPEED UP FOLDING DISULFIDE ISOMERASE PROLYL ISOMERASE G o SPEEDS UP PEPTIDE cis - trans INTERCHANGE. FOUND IN EVERY CELL! ~ RATE OF cis - trans = e-80/2.5 e- ∆ G o /RT = ~ 10-14 i.e. SLOW! cis CATALYZED RATE OF cis - trans ~ e- ∆ G o /RT = e-60/2.5 CATALYZED 20kJ/mole trans cis α α α SPEEDS UP DISULFIDE INTERCHANGE. FOUND IN EVERY CELL! X Y X Y α α trans cis PROLYL ISOMERASE LOWERS ∆ G o OF ISOMERIZATION BY ~ 20kJ/MOL, SPEEDING UP ISOMERIZATION BY ~ 3000x 80kJ/mol PROBABILITY TO HAVE EXTRA ENERGY BEYOND GROUND STATE REAL WORLD: PROTEIN RESCUE FROM MISFOLDING: MOLECULAR CHAPERONES 1. PREVENT PROTEIN AGGREGATION 2. PREVENT/CORRECT MISFOLDING START WITH ∆ G = ∆ H -T ∆ S AT HIGHER TEMP, HYDROPHOBIC EFFECT CAN BE INAPPROPRIATELY LARGE HEAT SHOCK PROTEINS : hsp, INDUCED WHEN BACTERIA ARE WARMED (e.g to 42 o )....
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This note was uploaded on 12/10/2011 for the course BCHEM 3350 taught by Professor Feig during the Fall '09 term at Cornell University (Engineering School).

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10 - LECTURE 10 ANNOUNCEMENTS 1 QUIZ 2A 23.3 2B 24.5 2C 23.9 2 NO LETTER GRADES AT THIS TIME A VERY ROUGH IDEA OF WHERE YOU STAND DIVIDE RAW SCORE

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