TCB Publications - Abstract
Paul W. King, Drazenka Svedruzic, Jordi Cohen, Klaus Schulten, Michael Seibert, and Maria L. Ghirardi. Structural and functional investigations of biological catalysts for optimization of solar-driven, H2 production systems. In Lionel Vayssieres, editor, Solar Hydrogen and Nanotechnology, volume 6340 of Proceedings of the Society of Photo-Optical Instrumentation Engineers, pp. 259-267, 2006.
production encompass a
variety of biological and chemical approaches. For solar-driven H production we are
investigating an approach that integrates biological catalysts, the [FeFe] hydrogenases,
with a photoelectrochemical cell as a novel bio-hybrid system. Structurally the [FeFe]
hydrogenases consist of an iron-sulfur catalytic site that in some instances is
electronically wired to accessory iron-sulfur clusters proposed to function in electron
transfer. The inherent structural complexity of most examples of these enzymes is
compensated by characteristics desired for bio-hybrid systems (i.e., low activation energy,
high catalytic activity and solubility) with the benefit of utilizing abundant, less costly non-
precious metals. Redesign and modification of [FeFe] hydrogenases is being undertaken to
reduce complexity and to optimize structural properties for various integration strategies.
The least complex examples of [FeFe] hydrogenase are found in the species of
photosynthetic green algae and are being studied as design models for investigating the
effects of structural minimization on substrate transfer, catalytic activity and oxygen
sensitivity. Redesigning hydrogenases for effective use in bio-hybrid systems requires a
detailed understanding of the relationship between structure and catalysis. To achieve
better mechanistic understanding of [FeFe] hydrogenases both structural and dynamic
models are being used to identify potential substrate transfer mechanisms which are
tested in an experimental system. Here we report on recent progress of our investigations
in the areas of [FeFe] hydrogenase expression, minimization and biochemical
characterization.
