Micro Mornings

B180 BBB


Doors open at 9:00am for socializing and breakfast

Wednesday, June 14, 2017

"Convergent evolution of respiratory complex I homologs with additional proton pumping capacity"

Gray Chadwick  

Orphan Lab

Respiratory complex I is a large multi-subunit membrane-bound protein complex that catalyzes the transfer of two electrons from NADH to ubiquinone with the concomitant pumping of protons across the cytoplasmic membrane. A modified complex I gene cassette in genome sequences from diverse archaeal and bacterial phyla encode a fourth proton pumping subunit. The incorporation of this extra subunit into a functional protein complex is supported by large amino acid insertions in the amphipathic helix that runs the full length of the protein complex. Phylogenetic relationships reveal that these modified complexes have arisen multiple separate times by convergent evolution.

“Following the electrons: Multiwavelength crystallographic oxidation state assignment of the nitrogenase iron protein"

Belinda Wenke

Rees Lab

Nitrogenase enzymes reduce atmospheric nitrogen to ammonia for incorporation into cellular material. Nitrogen reduction by nitrogenase is accomplished by sequential electron transfer between two component proteins and is controlled by ATP hydrolysis. The inter-protein electron transfer process during nitrogen reduction is of crucial mechanistic importance, and characterizing the reduction states of metals in the cofactor during catalysis is of significant interest. Here, we derive X-ray absorption information from high-resolution X-ray crystallographic data to determine oxidation states of an [4Fe:4S]. The experiments provide a path for describing the oxidation states of the nitrogenase complex, towards obtaining a mechanism for nitrogen reduction.

Upcoming MicroMornings

Wednesday, July 12, 2017

Fischer and Peters Labs

Wednesday, August 9, 2017

Shapiro and Sternberg Labs