Sulfate-reducing bacteria iron-sulfur proteins

SIMPLE AND COMPLEX IRON-SULFUR PROTEINS IN SULFATE REDUCING BACTERIA... 

This chapter will focus on simple and complex iron-sulfur-con-taining proteins isolated from sulfate reducing bacteria (SRB), in order to review the following topics types and distribution of proteins metal clusters involved and their association with other centers and... 

Simple and Complex Iron-Sulfur Proteins in Sulfate Reducing Bacteria... 

Simple and Complex Iron-Sulfur Proteins in Sulfate Reducing Bacteria Isabel Moura, Alice S. Pereira, Pedro Tavares, and Jose J. G, Moura... 

An interesting new tetranuclear iron hybrid cluster protein (HCP) has been observed and characterized from two sulfate reducing bacteria. Combined X-ray diffraction and EPR data showed that it contains both oxygen and sulfur bridges between the iron ions. The nature of the cluster was found to be independent of the presence or absence of oxygen in the sample preparation.247... 

Proteins with dinuclear iron centres comprise some prominent and well studied representatives like ribonucleotide reductase (RNR), purple acid phosphatase (PAP), methane monooxygenase hydroxylase (MMOH), ruberythrin and hemerythrin. The last of these is an oxygen carrier in some sea worms it has been well characterized within this group and has thus laid the foundation to this class of iron coordination motif. Ruberythrin is found in anaerobic sulfate-reducing bacteria. Its name implies that, in addition to a hemerythrin-related diiron site another iron is coordinated in a mononuclear fashion relating to rubredoxin, which is an iron-sulfur centre. The latter will not be treated here. The hydroxylase component of methane monooxygenase is one of the three components in soluble methane monooxygenase (MMO) and contains the active diiron site it is found in methanotropic bacteria. Purple add phosphatase (PAP) occurs mainly in plants and animals, and catalyses the hydrolysis of monophosphate esters. Finally, ribonucleotide reductase reduces ribonucleotides to deoxyribonucleotides and thus has a key position in DNA synthesis. 

In bacteria PAPS is a substrate for sulfate reduction. In plants, adenosine-5 -phosphosulfate is the substrate. Thioredoxin, a small thiol-containing protein, reduces the sulfate in PAPS to sulfite (SOS "). Sulfite is reduced by sulfite reductase in a six electron transfer through the intermediates NADPH, FAD, FMN, an iron-sulfur center, and the porphyrin siroheme. The end product is H2S. 

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