Post Doc @ Hoffman Lab
Post Doc @ Hoffman Lab
Post-doctoral positions in the group of
Professor Brian M. Hoffman of Northwestern University.
We determine the catalytic mechanisms of metalloenzymes through the development and implementation of electron-nuclear double resonance (ENDOR) spectroscopy, a combination of NMR and EPR. This technique is uniquely able to determine active site composition and electronic and geometric structures, not merely for an enzyme resting state but, most importantly, for key trapped catalytic and photogenerated intermediates. Characterization of key intermediates reveals mechanism!
Among the array of projects reflected in recent publications are ongoing studies of multiple central issues at the intersections of Inorganic Chemistry/Biochemistry/Biology. (i) Biological ‘nitrogen fixation’ – the reduction of N2 to two NH3 molecules by the enzyme nitrogenase – the source of ~50% of the N atoms in humans today; (ii) catalysis of H-atom transfer by enzymes of the vast radical SAM (S-adenosyl methionine) superfamily, comprising over 500,000 members, which initiate radical reactions by homolytic cleavage of SAM to form the highly reactive 5’-deoxyadenosyl radical (5’-dAdo•); (iii) Cu methane monooxygenase, which oxidizes methane to methanol and is central to mitigating emissions of methane, the potent greenhouse gas; (iv) in vivo speciation of Mn2+ as determined by EPR/ENDOR, for this cannot be achieved by cellular fractionation, thereby identifying Mn2+ complexes with roles as primary defender against radiation, in controlling vertebrate fertilization, and as indicators of the likelihood of the persistence of viable lifeforms on Mars(!).
Parallel studies of synthetic, biomimetic complexes provide constraints that help identify intermediates trapped during catalysis, and that are moreover of intrinsic importance as Jahn-Teller active systems that exhibit novel dynamic properties.
Selected recent publication illustrating these projects and exemplifying our approach can be found at the Northwestern Chemistry Department core-faculty website,
https://chemistry.northwestern.edu/people/core-faculty/profiles/brian-hoffman.html
Preferred background: Magnetic Resonance (EPR/ENDOR), and/or Biochemistry, and/or Computational Chemistry.
Contacts welcomed (bmh@northwestern.edu) with Skype/Zoom conversations to follow
