Similarities in the Architecture of the Active Sites of Ni‐Hydrogenases and Fe‐Hydrogenases Detected by Means of Infrared Spectroscopy

Abstract

Three groups that absorb in the 2100–1800‐cm−1 infrared spectral region have recently been detected in Ni‐hydrogenase from Chromatium vinosum [Bagley, K. A., Duin, E. C., Roseboom, W., Albracht, S. P. J. & Woodruff, W. H. (1995) Biochemistry 34, 5527–5535]. To assess the significance and generality of this observation, we have carried out an infrared‐spectroscopic study of eight hydrogenases of three different types (nickel, iron and metal‐free) and of 11 other iron‐sulfur and/or nickel proteins. Infrared bands in the 2100–1800‐cm−1 spectral region were found in spectra of all Ni‐hydrogenases and Fe‐hydrogenases and were absent from spectra of any of the other proteins, including a metal‐free hydrogenase. The positions of these bands are dependent on the redox state of the hydrogenase. The three groups in Ni‐hydrogenases that are detected by infrared spectroscopy are assigned to the three unidentified small non‐protein ligands that coordinate iron in the dinuclear Ni/Fe active site as observed in the X‐ray structure of the enzyme from Desulfovibrio gigas [Volbeda, A., Charon, M.‐H., Piras, C., Hatchikian, E. C., Frey, M. & Fontecilla‐Camps, J. C. (1995) Nature 373, 580–587]. It is concluded that these groups occur exclusively in metal‐containing H2‐activating enzymes. It is proposed that the active sites of Ni‐hydrogenases and of Fe‐hydrogenases have a similar architecture, that is required for the activation of molecular hydrogen.

New Insights into [FeFe] Hydrogenase Activation and Maturase Function

“…FTIR spectroscopy has historically been a useful technique to analyze metalloenzymes with iron clusters containing CO and CN – adducts since these species absorb in an infrared region that is not obscured by other protein-related substituents [9], [15], [21]. IR spectroscopy of 150 µM Strep -tag II–HydG in the as-isolated state (i.e.…”

Structural and Functional Analogues of the Active Sites of the [Fe]-, [NiFe]-, and [FeFe]-Hydrogenases

“…Spectroelectrochemical studies on the enzyme system and low-temperature FTIR/photolysis studies utilizing enzyme preparations from both DdH and CpI have provided an understanding of the interconversion of bridging and terminal CO states of the enzyme (Table 6). [138][139][140][141][142] These studies have been reviewed comprehensively in the "Hydrogen" issue. 42 In the H ox form of the enzyme, one CO occupies a bridging position.…”

Understanding 2D-IR Spectra of Hydrogenases: A Descriptive and Predictive Computational Study

“…As a consequence, spectroscopic techniques play a key role in hydrogenase research. Due to the presence of CO and CN − ligands, infrared (IR) spectroscopy has been extensively utilized to study hydrogenases since the first experimental observation of these unexpected diatomic ligands with this very technique [2,3,5,6,8,9]. In this respect, IR spectroscopy represents a particularly powerful method for studying hydrogenases for two major reasons.…”