Beyond Sustainability Communication: Sustainability-integrated Corporate Communications

Research on sustainable communication is mostly limited to sustainability communication without presenting a model of sustainable communication itself. As this article argues, two things can happen if communication itself does not follow the principles of sustainability: Sustainability communication will be less credible, and society will overlook the cornerstone of how to address and overcome discrepancies between corporate behaviour and corporate communicative behaviour. The fact that earth’s natural resources are limited, is not yet incorporated in corporate communication as practised by organisations. At the borders of sustainability and communication this paper therefore argues for the development and implementation of sustainability-integrated corporate communications

A Morphing [4Fe-3S-nO]-Cluster within a Carbon Monoxide Dehydrogenase Scaffold

Ni,Fe-containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of CO2 to CO. Several anaerobic microorganisms encode multiple CODHs in their genome, of which some, despite being annotated as CODHs, lack a cysteine of the canonical binding motif for the active site Ni,Fe-cluster. Here, we report on the structure and reactivity of such a deviant enzyme, termed CooS-VCh. Its structure reveals the typical CODH scaffold, but contains an iron-sulfur-oxo hybrid-cluster. Although closely related to true CODHs, CooS-VCh catalyzes neither CO oxidation, nor CO2 reduction. The active site of CooS-VCh undergoes a redox-dependent restructuring between a reduced [4Fe-3S]-cluster and an oxidized [4Fe-2S-S*-2O-2(H2O)]-cluster. Hydroxylamine, a slow-turnover substrate of CooS-VCh, oxidizes the hybrid-cluster in two structurally distinct steps. Overall, minor changes in CODHs are sufficient to accommodate a Fe/S/O-cluster in place of the Ni,Fe-heterocubane-cluster of CODHs

Expression and characterization of Pantoea CO dehydrogenase to utilize CO-containing industrial waste gas for expanding the versatility of CO dehydrogenase

Although aerobic CO dehydrogenases (CODHs) might be applicable in various fields, their practical applications have been hampered by low activity and no heterologous expression. We, for the first time, could functionally express recombinant PsCODH in E. coli and obtained a highly concentrated recombinant enzyme using an easy and convenient method. Its electron acceptor spectra, optimum conditions (pH 6.5 and 30 degrees C), and kinetic parameters (k(cat) of 12.97 s(-1), Km of 0.065 mM, and specific activity of 0.86 Umg(-1)) were examined. Blast furnace gas (BFG) containing 20% CO, which is a waste gas from the steel-making process, was tested as a substrate for PsCODH. Even with BFG, the recombinant PsCODH retained 88.2% and 108.4% activity compared with those of pure CO and 20% CO, respectively. The results provide not only a promising strategy to utilize CO-containing industrial waste gases as cheap, abundant, and renewable resources but also significant information for further studies about cascade reactions producing value-added chemicals via CO2 as an intermediate produced by a CODHbased CO-utilization system, which would ultimately expand the versatility of CODH.ope

Biochemische und strukturelle Untersuchungen der Kohlenmonoxid-Dehydrogenasen CODH-II und CODH-V aus Carboxydothermus hydrogenoformans

Eine Vielzahl strikt anaerober Organismen verwendet den reduktiven Acetyl-CoA-Weg zum autotrophen Wachstum mit Kohlenmonoxid als einziger Kohlenstoffquelle. Die Kohlenmonoxid-Dehydrogenase (CODH) ist das Schlüsselenzym dieses Stoffwechselweges und katalysiert die Oxidation von CO mit Raten von bis zu 31,000 s–1 und die Reduktion von CO2 mit bis zu 12 s–1 an einem [Ni4Fe4S-OHx]-Cluster (C-Cluster). Das Genom des thermophilen und hydrogenogenen Bakteriums Carboxydothermus hydrogenoformans enthält insgesamt fünf Gene, die für CODHs kodieren. Anhand der Genumgebung wurden dabei unterschiedliche Rollen für die einzelnen CODHs vorgeschlagen. Für ein besseres Verständnis der molekularen Prozesse in der Katalyse, wurden CODH-IICh und -VCh heterolog in Escherichia coli produziert und biochemisch und strukturell charakterisiert.A variety of strict anaerobic organisms employ the reductive acetyl-CoA path for autotrophic growth, using carbon monoxide as sole carbon source. Carbon monoxide dehydrogenase (CODH) is the key enzyme of the path and catalyzes CO oxidation with rates of 31,000 s–1 and CO2 reduction with rates of 12 s–1 at a [Ni4Fe4S-OHx] cluster (cluster C). The genome of the thermophilic and hydrogenogenic bacterium Carboxydothermus hydrogenoformans contains five copies of genes coding for the catalytic subunit of a CODH. According to the gene environment, different physiological roles for the individual CODHs were proposed. To compare their respective structure and catalytic function, CODH-IICh and -VCh were heterologously produced in Escherichia coli and biochemically and structurally investigated

A Morphing [4Fe 3S nO] Cluster within a Carbon Monoxide Dehydrogenase Scaffold

Ni,Fe containing carbon monoxide dehydrogenases CODHs catalyze the reversible reduction of CO2 to CO. Several anaerobic microorganisms encode multiple CODHs in their genome, of which some, despite being annotated as CODHs, lack a cysteine of the canonical binding motif for the active site Ni,Fe cluster. Here, we report on the structure and reactivity of such a deviant enzyme, termed CooS VCh. Its structure reveals the typical CODH scaffold, but contains an iron sulfur oxo hybrid cluster. Although closely related to true CODHs, CooS VCh catalyzes neither CO oxidation, nor CO2 reduction. The active site of CooS VCh undergoes a redox dependent restructuring between a reduced [4Fe 3S] cluster and an oxidized [4Fe 2S S 2O 2 H2O ] cluster. Hydroxylamine, a slow turnover substrate of CooS VCh, oxidizes the hybrid cluster in two structurally distinct steps. Overall, minor changes in CODHs are sufficient to accommodate a Fe S O cluster in place of the Ni,Fe heterocubane cluster of CODH

Structural basis for organohalide respiration

Organohalide-respiring microorganisms can use a variety of persistent pollutants including trichloroethene (TCE) as terminal electron acceptors. The final two-electron transfer step in organohalide respiration is catalyzed by reductive dehalogenases. Here we report the x-ray crystal structure of PceA, an archetypal dehalogenase from Sulfurospirillum multivorans, as well as structures of PceA in complex with TCE and product analogs. The active site harbors a deeply buried norpseudo-B12 cofactor within a nitroreductase fold, also found in a mammalian B12 chaperone. The structures of PceA reveal how a cobalamin supports a reductive haloelimination exploiting a conserved B12-binding scaffold capped by a highly variable substrate-capturing region