Properties of Human Tumor Suppressor 101F6 Protein as a Cytochrome b561 and Its Preliminary Crystallization Trials

Recuenco, Mariam C.; Watanabe, Soichi; Takeuchi, Fusako; Park, Sam-Yong; Tsubaki, Motonari

doi:10.5772/29306

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References 41 publications

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“…However, for other members of the cytochrome b 561 protein family, the presence of the ferric resuctase activity was not proved yet on the molecular level. 101F6 protein differs significantly from Cecytb-2 protein (or other classic members of cytochrome b 561 family) in amino acid sequences (belonging to a very distant subfamily) and in their biophysical properties (EPR spectra, redox potentials, reactivity with ascorbate) [24][25][26]. Therefore, the molecular mechanism of the ferric reductase activity of 101F6 may be very different from those of usual cytochromes b 561 .…”

Section: Introductionmentioning

confidence: 95%

Functional Assembly of Caenorhabditis elegans Cytochrome b-2 (Cecytb-2) into Phospholipid Bilayer Nanodisc with Enhanced Iron Reductase Activity

et al. 2021

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Among seven homologs of cytochrome b561 in a model organism C. elegans, Cecytb-2 was confirmed to be expressed in digestive organs and was considered as a homolog of human Dcytb functioning as a ferric reductase. Cecytb-2 protein was expressed in Pichia pastoris cells, purified, and reconstituted into a phospholipid bilayer nanodisc. The reconstituted Cecytb-2 in nanodisc environments was extremely stable and more reducible with ascorbate than in a detergent-micelle state. We confirmed the ferric reductase activity of Cecytb-2 by analyzing the oxidation of ferrous heme upon addition of ferric substrate under anaerobic conditions, where clear and saturable dependencies on the substrate concentrations following the Michaelis–Menten equation were observed. Further, we confirmed that the ferric substrate was converted to a ferrous state by using a nitroso-PSAP assay. Importantly, we observed that the ferric reductase activity of Cecytb-2 became enhanced in the phospholipid bilayer nanodisc.

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Section: Introductionmentioning

confidence: 95%