A5021496400- Microbial metabolism and enzyme function
- Metal-Catalyzed Oxygenation Mechanisms
- Microbial bioremediation and biosurfactants
- Porphyrin Metabolism and Disorders
- Anaerobic Digestion and Biogas Production
- Methane Hydrates and Related Phenomena
- Trace Elements in Health
- Hemoglobin structure and function
- Microbial Community Ecology and Physiology
- Chromium effects and bioremediation
- Radioactive element chemistry and processing
- Photosynthetic Processes and Mechanisms
- Heme Oxygenase-1 and Carbon Monoxide
- Metal Extraction and Bioleaching
- Iron Metabolism and Disorders
- Heavy Metal Exposure and Toxicity
- Biofuel production and bioconversion
- Metalloenzymes and iron-sulfur proteins
- Microbial Fuel Cells and Bioremediation
- Enzyme Structure and Function
- Odor and Emission Control Technologies
- Corrosion Behavior and Inhibition
- Mercury impact and mitigation studies
- Minerals Flotation and Separation Techniques
- Amino Acid Enzymes and Metabolism
Iowa State University
2015-2024
Ames National Laboratory
2007-2011
University of Iowa
2010
University of Minnesota
1985-2008
University of Wisconsin–Eau Claire
2006-2008
Carnegie Mellon University
2007
University of Michigan
2006-2007
Medical College of Wisconsin
2006-2007
Montana State University
2006
University of Kansas
2004
Siderophores are extracellular iron-binding compounds that mediate iron transport into many cells. We present evidence of analogous molecules for copper from methane-oxidizing bacteria, represented here by a small fluorescent chromopeptide (C45N12O14H62Cu, 1216 daltons) produced Methylosinus trichosporium OB3b. The crystal structure this compound, methanobactin, was resolved to 1.15 angstroms. It is composed tetrapeptide, tripeptide, and several unusual moieties, including two...
An active preparation of the membrane-associated methane monooxygenase (pMMO) from Methylococcus capsulatus Bath was isolated by ion-exchange and hydrophobic interaction chromatography using dodecyl beta-D-maltoside as detergent. The consisted three major polypeptides with molecular masses 47,000, 27,000, 25,000 Da. Two (those 47,000 27,000 Da) were identified induced when cells expressing soluble MMO are switched to culture medium in which pMMO is expressed. 27,000-Da polypeptide...
Abstract Analytical methods for monitoring the volatile organic compound (VOC) emissions, defining atmospheric transport coefficients, and solution phase chemistry have been developed to define processes regulating emission of malodorous other VOCs from a high odor swine production facility. Of 40 compounds identified in liquid outdoor air samples facility, 27 were confirmed contribute decreased quality vicinity Specifically, C2 through C9 acids demonstrated greatest potential quality, since...
Improvements in purification of membrane-associated methane monooxygenase (pMMO) have resulted preparations pMMO with activities more representative physiological rates: i.e., >130 nmol.min(-1).mg protein(-1). Altered culture and assay conditions, optimization the detergent/protein ratio, simplification procedure were responsible for higher-activity preparations. Changes conditions focused on rate copper addition. To document events that occur during addition, cultures initiated medium cells...
Wilson disease (WD) is a rare hereditary condition that caused by genetic defect in the copper-transporting ATPase ATP7B results hepatic copper accumulation and lethal liver failure. The present study focuses on structural mitochondrial alterations precede clinical symptoms livers of rats lacking Atp7b, an animal model for WD. Liver mitochondria from these Atp7b–/– contained enlarged cristae widened intermembrane spaces, which coincided with massive copper. These changes, however, preceded...
In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive accumulation in the liver and fulminant hepatitis. Current US Food Drug Administration- European Medicines Agency-approved pharmacological treatments usually fail restore homeostasis patients with WD who have progressed acute failure, leaving transplantation as only viable treatment option. Here, we investigated therapeutic utility methanobactin (MB), a...
Biological oxidation of methane to methanol by aerobic bacteria is catalysed two different enzymes, the cytoplasmic or soluble monooxygenase (sMMO) and membrane-bound particulate (pMMO). Expression MMOs controlled a 'copper-switch', i.e. sMMO only expressed at very low copper : biomass ratios, while pMMO expression increases as this ratio increases. Methanotrophs synthesize chalkophore, methanobactin, for binding import copper. Previous work suggested that methanobactin was formed from...
Methylmercury (CH3Hg+) is a potent neurotoxin produced by certain anaerobic microorganisms in natural environments. Although numerous studies have characterized the basis of mercury (Hg) methylation, no examined CH3Hg+ degradation methanotrophs, despite their ubiquitous presence environment. We report that some such as Methylosinus trichosporium OB3b, can take up and degrade rapidly, whereas others, Methylococcus capsulatus Bath, but not CH3Hg+. Demethylation M. OB3b increases with...
Excess copper causes hepatocyte death in hereditary Wilson's disease (WD). Current WD treatments by copper-binding chelators may gradually reduce overload; they fail, however, to bring hepatic close normal physiological levels. Consequently, lifelong daily dose regimens are required hinder progression. This result severe issues due nonadherence or unwanted adverse drug reactions and also switching ultimate treatment failures. study comparatively tested bacteria-derived binding...
ABSTRACT Direct multicomponent analysis of malodorous volatile organic compounds (VOCs) present in ambient air samples from 29 swine ( Sus scrofa ) production facilities was used to develop a 19‐component artificial odor solution that simulated olfactory properties effluent. Analyses employing either human panel consisting 14 subjects or gas chromatography were performed on the stream an emission chamber assess responses odorant concentration, respectively. Analysis using Fisher's LSD...
To examine the potential role of methanobactin (mb) as extracellular component a copper acquisition system in Methylosinus trichosporium OB3b, metal binding properties mb were examined. Spectral (UV−visible, fluorescence, and circular dichroism), kinetic, thermodynamic data suggested coordination changes at different Cu(II):mb ratios. Mb appeared to initially bind Cu(II) homodimer with comparatively high affinity ratios below 0.2, constant (K) greater than that EDTA (log K = 18.8) an...
Methanobactin (mb) is a small copper-binding peptide produced by methanotrophic bacteria and intimately involved in both their copper metabolism role the global carbon cycle. The structure for methanobactin comprises seven amino acids plus two chromophoric residues that appear unique to methanobactin. In previously published structure, contain thiocarbonyl attached hydroxyimidazolate ring. addition, one pyrrolidine ring, while other an isopropyl ester. A X-ray determined shows these groups...
Two methane monooxygenase (MMO) systems have been identified in methanotrophic bacteria, namely, a soluble or cytoplasmic MMO and membrane-associated particulate MMO. The active site of the well-characterized contains bis-μ-hydroxo-bridged diiron cluster. X-ray crystallographic studies enzyme, pMMO, two copper centers on α subunit (pmoB) αβγ trimer at interface βγ subunits filled by Zn, apparently from crystallization buffer. In our hands, pMMO preparations containing 1−2 iron atoms per show...
Methylosinus trichosporium OB3b (for "oddball" strain 3b) is an obligate aerobic methane-oxidizing alphaproteobacterium that was originally isolated in 1970 by Roger Whittenbury and colleagues. This has since been used extensively to elucidate the structure function of several key enzymes methane oxidation, including both particulate soluble monooxygenase (sMMO) extracellular copper chelator methanobactin. In particular, catalytic properties from M. have well characterized context with...
The ability of ferrous hemoglobins to reduce nitrite form nitric oxide has been demonstrated for from animals, including myoglobin, blood cell hemoglobin, neuroglobin, and cytoglobin. In all cases, the rate constants bimolecular reactions with are relatively slow, maximal values ~5 M(-1) s(-1) at pH 7. Combined low concentrations found in animal plasma (normally no greater than 13 μM), these slow reaction rates unlikely contribute significantly hemoglobin oxidation, reduction, or NO...
A non-motile strain of Methylocystis, SB2, isolated from a spring bog in southeast Michigan, had curved rod morphology with typical type II intracytoplasmic membrane system. This organism expressed the membrane-bound or particulate methane monooxygenase (pMMO) as well chalkophore high affinity for copper and did not express cytoplasmic soluble (sMMO). Strain SB2 was found to grow within pH range 6-9, optimal growth at 6.8. Growth observed temperatures ranging between 10°C 30°C, no 37°C. The...
Methanobactins (mb) are low-molecular mass, copper-binding molecules secreted by most methanotrophic bacteria. These have been identified for a number of methanotrophs, but only the one produced Methylosinus trichosporium OB3b (mb-OB3b) has to date chemically characterized. Here we report chemical characterization and copper binding properties second methanobactin, which is Methylocystis strain SB2 (mb-SB2). mb-SB2 shows some significant similarities mb-OB3b, including its spectral metal...
Methanotrophs have multiple methane monooxygenases that are well known to be regulated by copper, i.e., a "copper switch." At low copper/biomass ratios the soluble monooxygenase (sMMO) is expressed while expression and activity of particulate (pMMO) increases with increasing availability copper. In many methanotrophs there also methanol dehydrogenases (MeDHs), one based on Mxa another Xox. Mxa-MeDH calcium in its active site, Xox-MeDHs been shown rare earth elements their site. We show here...
It is well known that Methylosinus trichosporium OB3b has two forms of methane monooxygenase (MMO) responsible for the initial conversion to methanol, a cytoplasmic (soluble) and membrane-associated (particulate) monooxygenase, copper strongly regulates expression these alternative MMO. More recently, it been discovered M. multiple types methanol dehydrogenase (MeDH), i.e. Mxa-type MeDH (Mxa-MeDH) Xox-type (Xox-MeDH), regulated by availability rare earth element (REE), cerium. Here, we...