Journal: bioRxiv
Article Title: Cryo-EM structure and kinetics reveal electron transfer by 2D diffusion of cytochrome c in the yeast III-IV respiratory supercomplex
doi: 10.1101/2020.11.27.401935
Figure Lengend Snippet: ( A ) The CIII 2 CIV 1/2 supercomplex (SC) QH 2 :O 2 oxidoreductase activity at different concentrations of S. cerevisiae or equine cyt. c . ( B ) The supercomplex QH 2 :O 2 oxidoreductase activity at 20 nM cyt. c with intact (SC) and dissociated supercomplexes after incubation in DDM (SC+DDM). The cyt. c oxidation-O 2 reduction activity was measured for CIV within a supercomplex (CIV in SC), for isolated CIV in GDN (from CIV peak in Fig. S1A ), or after incubation in DDM (CIV in DDM). ( C ) The QH 2 :O 2 oxidoreductase activity of the supercomplex at 50 μM cyt. c with intact (SC) and after dissociation of the supercomplex in DDM (SC+DDM). The maximum activities of CIII and CIV are also shown. Error bars are ±SD for three technical replicates from two independent preparations (except the 200-nM point in panel A, which is an average of a total of five replicates). For some points the error bars are smaller than the symbols. The solid lines were generated using Michaelis–Menten equations with K m values 6 nM and 1.7 μM (yeast cyt. c ) or 0.2 μM and 15 μM (horse cyt. c ).
Article Snippet: A baseline absorbance was first recorded with 50 μM oxidized cyt. c from S. cerevisiae (Sigma), CIII 2 CIV 1/2 supercomplex (equivalent of 20 nM CIIICIV), 2 mM KCN (to block cyt. c oxidation by CIV) in 150 mM KCl, 20 mM KPi buffer, pH 7.4, 0.01 % GDN.
Techniques: Activity Assay, Incubation, Isolation, Generated
