Oxygen detoxification in the strict anaerobic archaeon Archaeoglobus fulgidus: superoxide scavenging by neelaredoxin.
Isabel A. Abreu,Lígia M. Saraiva,João Carita,Harald Huber,Karl O. Stetter,Diane E. Cabelli,Miguel Teixeira +6 more
TLDR
It is shown that neelaredoxin (Nlr) is the main O2·− scavenger in A. fulgidus and shown that Nlr is able to both reduce and dismutate O 2·−, thus having a bifunctional reactivity towards O2 ·−.Abstract:
Archaeoglobus fulgidus is a hyperthermophilic sulphate-reducing archaeon. It has an optimum growth temperature of 83°C and is described as a strict anaerobe. Its genome lacks any homologue of canonical superoxide (O2·−) dismutases. In this work, we show that neelaredoxin (Nlr) is the main O2·− scavenger in A. fulgidus, by studying both the wild-type and recombinant proteins. Nlr is a 125-amino-acid blue-coloured protein containing a single iron atom/molecule, which in the oxidized state is high spin ferric. This iron centre has a reduction potential of +230 mV at pH 7.0. Nitroblue tetrazolium-stained gel assays of cell-soluble extracts show that Nlr is the main protein from A. fulgidus which is reactive towards O2·−. Furthermore, it is shown that Nlr is able to both reduce and dismutate O2·−, thus having a bifunctional reactivity towards O2·−. Kinetic and spectroscopic studies indicate that Nlr's superoxide reductase activity may allow the cell to eliminate O2·− quickly in a NAD(P)H-dependent pathway. On the other hand, Nlr's superoxide dismutation activity will allow the cell to detoxify O2·− independently of the cell redox status. Its superoxide dismutase activity was estimated to be 59 U mg−1 by the xanthine/xanthine oxidase assay at 25°C. Pulse radiolysis studies with the isolated and reduced Nlr proved unambiguously that it has superoxide dismutase activity; at pH 7.1 and 83°C, the rate constant is 5 × 106 M−1 s−1. Besides the superoxide dismutase activity, soluble cell extracts of A. fulgidus also exhibit catalase and NAD(P)H/oxygen oxidoreductase activities. By putting these findings together with the entire genomic data available, a possible oxygen detoxification mechanism in A. fulgidus is discussed.read more
Citations
More filters
Journal ArticleDOI
Superoxide dismutases and superoxide reductases
Yuewei Sheng,Isabel A. Abreu,Diane E. Cabelli,Michael J. Maroney,Anne-Frances Miller,Miguel Teixeira,Joan Selverstone Valentine,Joan Selverstone Valentine +7 more
TL;DR: The SORs and three very different types of SOD enzymes are redox-active metalloenzymes that have evolved entirely independently from one another for the purpose of lowering superoxide concentrations, suggesting that, from the start of the rise of O2 on Earth, the chemistry of superoxide has been an important factor during evolution.
Journal ArticleDOI
Metalloproteins containing cytochrome, iron-sulfur, or copper redox centers.
Jing Liu,Saumen Chakraborty,Parisa Hosseinzadeh,Yang Yu,Shiliang Tian,Igor D. Petrik,Ambika Bhagi,Yi Lu +7 more
TL;DR: Through this review, structural features responsible for their redox properties are examined, including knowledge gained from recent progress in fine-tuning the redox centers.
Journal ArticleDOI
Synthetic analogues of cysteinate-ligated non-heme iron and non-corrinoid cobalt enzymes
TL;DR: Making Low-Spin Co(III) More Reactive 840 3.2.1.
Book ChapterDOI
How oxygen damages microbes: oxygen tolerance and obligate anaerobiosis
TL;DR: Adaptive strategies by which obligate anaerobes seek to minimize the damage done by superoxide and hydrogen peroxide are uncovered, indicating that important aspects of oxidative stress still lack a biochemical explanation.
Book ChapterDOI
A Post-Genomic View of the Ecophysiology, Catabolism and Biotechnological Relevance of Sulphate-Reducing Prokaryotes
Ralf Rabus,Sofia S. Venceslau,Lars Wöhlbrand,Gerrit Voordouw,Judy D. Wall,Inês A. C. Pereira +5 more
TL;DR: The wealth of publications in this period is a testimony to the large environmental, biogeochemical and technological relevance of these organisms and how much the field has progressed in these years, although many important questions and applications remain to be explored.
References
More filters
Journal ArticleDOI
Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products.
Journal Article
Cleavage of structural proteins during the assemble of the head of bacterio-phage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products as mentioned in this paper.
Journal ArticleDOI
Clustal w: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice
TL;DR: The sensitivity of the commonly used progressive multiple sequence alignment method has been greatly improved and modifications are incorporated into a new program, CLUSTAL W, which is freely available.
PatentDOI
Measurement of protein using bicinchoninic acid
TL;DR: This new method maintains the high sensitivity and low protein-to-protein variation associated with the Lowry technique and demonstrates a greater tolerance of the bicinchoninate reagent toward such commonly encountered interferences as nonionic detergents and simple buffer salts.
Journal ArticleDOI
Superoxide Dismutase AN ENZYMIC FUNCTION FOR ERYTHROCUPREIN (HEMOCUPREIN)
Joe M. McCord,Irwin Fridovich +1 more
TL;DR: The demonstration that O2·- can reduce ferricytochrome c and tetranitromethane, and that superoxide dismutase, by competing for the superoxide radicals, can markedly inhibit these reactions, is demonstrated.