Hydrogenases in Desulfovibrio vulgaris Hildenborough: structural and physiologic characterisation of the membrane-bound [NiFeSe] hydrogenase

Abstract

The genome of Desulfovibrio vulgaris Hildenborough (DvH) encodes for six hydrogenases (Hases), making it an interesting organism to study the role of these proteins in sulphate respiration. In this work we address the role of the [NiFeSe] Hase, found to be the major Hase associated with the cytoplasmic membrane. The purified enzyme displays interesting catalytic properties, such as a very high H(2) production activity, which is dependent on the presence of phospholipids or detergent, and resistance to oxygen inactivation since it is isolated aerobically in a Ni(II) oxidation state. Evidence was obtained that the [NiFeSe] Hase is post-translationally modified to include a hydrophobic group bound to the N-terminal, which is responsible for its membrane association. Cleavage of this group originates a soluble, less active form of the enzyme. Sequence analysis shows that [NiFeSe] Hases from Desulfovibrionacae form a separate family from the [NiFe] enzymes of these organisms, and are more closely related to [NiFe] Hases from more distant bacterial species that have a medial [4Fe4S](2+/1+) cluster, but not a selenocysteine. The interaction of the [NiFeSe] Hase with periplasmic cytochromes was investigated and is similar to the [NiFe](1) Hase, with the Type I cytochrome c (3) as the preferred electron acceptor. A model of the DvH [NiFeSe] Hase was generated based on the structure of the Desulfomicrobium baculatum enzyme. The structures of the two [NiFeSe] Hases are compared with the structures of [NiFe] Hases, to evaluate the consensual structural differences between the two families. Several conserved residues close to the redox centres were identified, which may be relevant to the higher activity displayed by [NiFeSe] Hases.

H2‐Fueled ATP Synthesis on an Electrode: Mimicking Cellular Respiration

“…The NiFeSe Hase from Desulfovibrio vulgaris Hildenborough was isolated and purified as reported previously 24, 25. F 1 F 0 ‐ATPase from E .…”

Transcriptional response of Desulfovibrio vulgaris Hildenborough to oxidative stress mimicking environmental conditions

“…In the present work the genes for the periplasmic hydrogenases (Valente et al 2006). Since the [NiFeSe] hydrogenase is much less sensitive to oxygen than the other periplasmic hydrogenases (Valente et al 2005), it makes sense that it should be up-regulated in these conditions.…”

Nickel–Iron–Selenium Hydrogenases – An Overview

“…baculatum [20] , and Desulfovibrio vulgaris Hildenborough [21] , which are group 1 uptake Hases, and from the methanogens Methanococcus vannielii [22] and Methanococcus voltae [23] , which are group 3 cytoplasmic Hases. We performed a survey of [NiFeSe] Hase sequences currently present in databases (September 2010).…”

“…The presence of Sec was manually checked in doubtful cases, and it was found that some Hases annotated as being [NiFeSe] [25] . The enzyme from D. vulgaris Hildenborough has been shown to be a lipoprotein, and thus to associate to the membrane through a lipidic group at the N-terminus of the large subunit [21,26] . It has a truncated lipoprotein signal peptide, restricted to the lipobox, and was the first lipoprotein shown to be translocated through the Tat, rather than the Sec, pathway [26] .…”

“…It has a truncated lipoprotein signal peptide, restricted to the lipobox, and was the first lipoprotein shown to be translocated through the Tat, rather than the Sec, pathway [26] . Hase from the same organism [21] , suggesting it did not originate from gene duplication but was acquired through lateral gene transfer followed by a Cys-to-Sec replacement. Sequence (Figure 1).…”