Extra creditExploring biological functionalityThe biological nitrogen cycleSlide 4Slide 5Slide 6Industrial Haber process (N2 -> NH3)Dinitrogenase model compoundOxygen binding in bodyYou will make model compound, Co(salen)Oxygen binding depends on Co environmentExperimental apparatus for measuring O2 bindingExtra credit•Extra credit 1 – ionic radii trends•Extra credit 2 – solving MIMT single crystal structures•Work on these must be completed individually. •Due date: May 14thExploring biological functionality•Enzymes–Complex systems that often contain metals at active site–Metals are particularly import for redox enzymes•Bio-inorganic chemistry–Synthesis of model compoundsThe biological nitrogen cycleNitrogenaseNitrogenase consists of 2 proteins: dinitrogenase reductase and dinitrogenaseOverall reactiondinitrogenase reductasedinitrogenase16 ATP required for each reduction of N2 -> 2 NH3Some bacteria fix nitrogen only when involved in a symbiotic relationship with plantsLeghemoglobin protects nitrogenase by binding oxygenA true cross-species collaboration:Plant makes the globin protein and bacterium makes the heme cofactorIndustrial Haber process (N2 -> NH3)T = 400-500 °Cp = 300-1000 atmDinitrogenase model compoundOxygen binding in bodyYou will make model compound, Co(salen)•Co(salen) can bind oxygen, just like the biological heme moleculeNNNNHOOOHOFerrous HemeFe2+NONOCoCo(salen)NONOCoCo(salen)NHONOHOOHNH2H2Nensal+ 2salenH2Co(II)Oxygen binding depends on Co environment•Co(salen) exists with Co in a 4, 5, or 6 coordinate site•Solvated Co(salen) only binds O2 when it is 5 or 6 coordinateNONOCoActive structureNONOCoNONOCoNONOCoInactive structureNONOCo2:1 structureNONOCoOOSolSolNONOCo1:1 structureOOSol•In crystals:•Solvated:Experimental apparatus for measuring O2 bindingstoppervac. flaskwatergraduatedpipettetubingCo(salen)DMSO in
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