@article{BoehmerHartmannLeimkuehler2014, author = {Boehmer, Nadine and Hartmann, Tobias and Leimk{\"u}hler, Silke}, title = {The chaperone FdsC for Rhodobacter capsulatus formate dehydrogenase binds the bis-molybdopterin guanine dinucleotide cofactor}, series = {FEBS letters : the journal for rapid publication of short reports in molecular biosciences}, volume = {588}, journal = {FEBS letters : the journal for rapid publication of short reports in molecular biosciences}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0014-5793}, doi = {10.1016/j.febslet.2013.12.033}, pages = {531 -- 537}, year = {2014}, abstract = {Molybdoenzymes are complex enzymes in which the molybdenum cofactor (Moco) is deeply buried in the enzyme. Most molybdoenzymes contain a specific chaperone for the insertion of Moco. For the formate dehydrogenase FdsGBA from Rhodobacter capsulatus the two chaperones FdsC and FdsD were identified to be essential for enzyme activity, but are not a subunit of the mature enzyme. Here, we purified and characterized the FdsC protein after heterologous expression in Escherichia coli. We were able to copurify FdsC with the bound Moco derivate bis-molybdopterin guanine dinucleotide. This cofactor successfully was used as a source to reconstitute the activity of molybdoenzymes. Structured summary of protein interactions: FdsC and FdsC bind by molecular sieving (View interaction) FdsD binds to RcMobA by surface plasmon resonance (View interaction) FdsC binds to RcMobA by surface plasmon resonance (View interaction) FdsC binds to FdsA by surface plasmon resonance (View interaction)}, language = {en} } @misc{HartmannSchwanholdLeimkuehler2015, author = {Hartmann, Tobias and Schwanhold, Nadine and Leimk{\"u}hler, Silke}, title = {Assembly and catalysis of molybdenum or tungsten-containing formate dehydrogenases from bacteria}, series = {Biochimica et biophysica acta : Proteins and proteomics}, volume = {1854}, journal = {Biochimica et biophysica acta : Proteins and proteomics}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1570-9639}, doi = {10.1016/j.bbapap.2014.12.006}, pages = {1090 -- 1100}, year = {2015}, abstract = {The global carbon cycle depends on the biological transformations of C-1 compounds, which include the reductive incorporation of CO2 into organic molecules (e.g. in photosynthesis and other autotrophic pathways), in addition to the production of CO2 from formate, a reaction that is catalyzed by formate dehydrogenases (FDHs). FDHs catalyze, in general, the oxidation of formate to CO2 and H+. However, selected enzymes were identified to act as CO2 reductases, which are able to reduce CO2 to formate under physiological conditions. This reaction is of interest for the generation of formate as a convenient storage form of H-2 for future applications. Cofactor-containing FDHs are found in anaerobic bacteria and archaea, in addition to facultative anaerobic or aerobic bacteria. These enzymes are highly diverse and employ different cofactors such as the molybdenum cofactor (Moco), FeS clusters and flavins, or cytochromes. Some enzymes include tungsten (W) in place of molybdenum (Mo) at the active site. For catalytic activity, a selenocysteine (SeCys) or cysteine (Cys) ligand at the Mo atom in the active site is essential for the reaction. This review will focus on the characterization of Mo- and W-containing FDHs from bacteria, their active site structure, subunit compositions and its proposed catalytic mechanism. We will give an overview on the different mechanisms of substrate conversion available so far, in addition to providing an outlook on bio-applications of FDHs. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{ReegJungCastroetal.2016, author = {Reeg, Sandra and Jung, Tobias and Castro, Jos{\´e} Pedro and Davies, Kelvin J. A. and Henze, Andrea and Grune, Tilman}, title = {The molecular chaperone Hsp70 promotes the proteolytic removal of oxidatively damaged proteins by the proteasome}, series = {Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research}, volume = {99}, journal = {Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research}, publisher = {Elsevier}, address = {New York}, issn = {0891-5849}, doi = {10.1016/j.freeradbiomed.2016.08.002}, pages = {153 -- 166}, year = {2016}, abstract = {One hallmark of aging is the accumulation of protein aggregates, promoted by the unfolding of oxidized proteins. Unraveling the mechanism by which oxidized proteins are degraded may provide a basis to delay the early onset of features, such as protein aggregate formation, that contribute to the aging phenotype. In order to prevent aggregation of oxidized proteins, cells recur to the 20S proteasome, an efficient turnover proteolysis complex. It has previously been shown that upon oxidative stress the 26S proteasome, another form, dissociates into the 20S form. A critical player implicated in its dissociation is the Heat Shock Protein 70 (Hsp70), which promotes an increase in free 20S proteasome and, therefore, an increased capability to degrade oxidized proteins. The aim of this study was to test whether or not Hsp70 is involved in cooperating with the 20S proteasome for a selective degradation of oxidatively damaged proteins. Our results demonstrate that Hsp70 expression is induced in HT22 cells as a result of mild oxidative stress conditions. Furthermore, Hsp70 prevents the accumulation of oxidized proteins and directly promotes their degradation by the 20S proteasome. In contrast the expression of the Heat shock cognate protein 70 (Hsc70) was not changed in recovery after oxidative stress and Hsc70 has no influence on the removal of oxidatively damaged proteins. We were able to demonstrate in HT22 cells, in brain homogenates from 129/SV mice and in vitro, that there is an increased interaction of Hsp70 with oxidized proteins, but also with the 20S proteasome, indicating a role of Hsp70 in mediating the interaction of oxidized proteins with the 20S proteasome. Thus, our data clearly implicate an involvement of Hsp70 oxidatively damaged protein degradation by the 20S proteasome. c) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).}, language = {en} }