James A Cracknell

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Knallgas bacteria such as certain Ralstonia spp. are able to obtain metabolic energy by oxidizing trace levels of H2 using O2 as the terminal electron acceptor. The [NiFe] hydrogenases produced by these organisms are unusual in their ability to oxidize H2 in the presence of O2, which is a potent inactivator of most hydrogenases through attack at the active(More)
Hydrogenases provide an inspiration for future energy technologies. The active sites of these microbial enzymes contain Fe or Ni and Fe coordinated by CO and CN ligands: yet they have activities for hydrogen cycling that compare with Pt catalysts. Is there a future for enzymes in technological H2 cycling? There are obviously going to be disadvantages,(More)
The electrophoretic translocation of polynucleotides through nanopores may permit direct single-molecule nucleic acid sequencing. Here we describe the translocation of ssRNA heteropolymers (91-6083 bases) through the α-hemolysin nanopore. Translocation of these long ssRNAs is characterized by surprisingly long, almost complete ionic current blockades with(More)
Use of hydrogen in fuel cells requires catalysts that are tolerant to oxygen and are able to function in the presence of poisons such as carbon monoxide. Hydrogen-cycling catalysts are widespread in the bacterial world in the form of hydrogenases, enzymes with unusual active sites composed of iron, or nickel and iron, that are buried within the protein. We(More)
In biology, rapid oxidation and evolution of H(2) is catalyzed by metalloenzymes known as hydrogenases. These enzymes have unusual active sites, consisting of iron complexed by carbonyl, cyanide, and thiolate ligands, often together with nickel, and are typically inhibited or irreversibly damaged by O(2). The Knallgas bacterium Ralstonia eutropha H16 (Re)(More)
The blue multi-copper oxidase bilirubin oxidase (BOx) from the ascomycete plant pathogen Myrothecium verrucaria (Mv) efficiently catalyses the oxidation of bilirubin to biliverdin, with the concomitant reduction of O(2) to water, a reaction of considerable interest for low-temperature bio-fuel cell applications. We have solved the complete X-ray determined(More)
This tutorial review describes studies of hydrogen production and oxidation by biological catalysts--metalloenzymes known as hydrogenases--attached to electrodes. It explains how the electrocatalytic properties of hydrogenases are studied using specialised electrochemical techniques and how the data are interpreted to allow assessments of catalytic rates(More)
Studies have been carried out to establish the ability of O2-tolerant membrane-bound [NiFe] hydrogenases (MBH) from Ralstonia sp. to catalyze H2 production in addition to H2 oxidation. These hydrogenases are not noted for H2-evolution activity, and this is partly due to strong product inhibition. However, when adsorbed on a rotating disk graphite electrode(More)