Structural Determinants of the Specific Activities of an L-Amino Acid Oxidase from CPMOR-1 with Broad Substrate Specificity.

The strain CPMOR-1 expresses a flavin adenine dinucleotide (FAD)-dependent L-amino acid oxidase (LAAO) with broad substrate specificity. Steady-state kinetic analysis of its reactivity towards the 20 proteinogenic amino acids showed some activity to all except proline. The relative specific activity for amino acid substrates was not correlated only with or values, since the two parameters often varied independently of each other.

Roles of active-site residues in catalysis, substrate binding, cooperativity, and the reaction mechanism of the quinoprotein glycine oxidase.

The quinoprotein glycine oxidase from the marine bacterium (PlGoxA) uses a protein-derived cysteine tryptophylquinone (CTQ) cofactor to catalyze conversion of glycine to glyoxylate and ammonia. This homotetrameric enzyme exhibits strong cooperativity toward glycine binding. It is a good model for studying enzyme kinetics and cooperativity, specifically for being able to separate those aspects of protein function through directed mutagenesis.

Kinetic and structural evidence that Asp-678 plays multiple roles in catalysis by the quinoprotein glycine oxidase.

PlGoxA from is a glycine oxidase that utilizes a protein-derived cysteine tryptophylquinone (CTQ) cofactor. A notable feature of its catalytic mechanism is that it forms a stable product-reduced CTQ adduct that is not hydrolyzed in the absence of O Asp-678 resides near the quinone moiety of PlGoxA, and an Asp is structurally conserved in this position in all tryptophylquinone enzymes. In those other enzymes, mutation of that Asp results in no or negligible CTQ formation.

The effects of dietary fatty acids in the physiological outcomes of maternal high-fat diet on offspring energy homeostasis in mice.

The early-life origins of disease hypothesis has been applied to obesity research and modeled through overnutrition, usually with a high-fat diet (HFD). Since the obesity epidemic coincided with societal change in dietary fat consumption, rather than amount, manipulation of fatty acid (FA) profile is an under-investigated area of study. Additionally, the binding of FAs to nuclear receptors may have persistent intergenerational, extranutritive endocrinological effects that interact with the actions of reproductive steroids causing sex-dependent effects.

The loss of ERE-dependent ERα signaling potentiates the effects of maternal high-fat diet on energy homeostasis in female offspring fed an obesogenic diet.

Maternal high-fat diet (HFD) alters hypothalamic programming and disrupts offspring energy homeostasis in rodents. We previously reported that the loss of ERα signaling partially blocks the effects of maternal HFD in female offspring fed a standard chow diet. In a companion study, we determined if the effects of maternal HFD were magnified by an adult obesogenic diet in our transgenic mouse models.

Characterization of PlGoxB, a flavoprotein required for cysteine tryptophylquinone biosynthesis in glycine oxidase from Pseudoalteromonas luteoviolacea.

LodA-like proteins are oxidases with a protein-derived cysteine tryptophylquinone (CTQ) prosthetic group. In Pseudoalteromonas luteoviolacea glycine oxidase (PlGoxA), CTQ biosynthesis requires post-translational modifications catalyzed by a modifying enzyme encoded by PlgoxB. The PlGoxB protein was expressed and shown to possess a flavin cofactor.

Structural and Spectroscopic Characterization of a Product Schiff Base Intermediate in the Reaction of the Quinoprotein Glycine Oxidase, GoxA.

The LodA-like proteins make up a recently identified family of enzymes that rely on a cysteine tryptophylquinone cofactor for catalysis. They differ from other tryptophylquinone enzymes in that they are oxidases rather than dehydrogenases. GoxA is a member of this family that catalyzes the oxidative deamination of glycine.

Structure and Enzymatic Properties of an Unusual Cysteine Tryptophylquinone-Dependent Glycine Oxidase from Pseudoalteromonas luteoviolacea.

Glycine oxidase from Pseudoalteromonas luteoviolacea (PlGoxA) is a cysteine tryptophylquinone (CTQ)-dependent enzyme. Sequence analysis and phylogenetic analysis place it in a newly designated subgroup (group IID) of a recently identified family of LodA-like proteins, which are predicted to possess CTQ. The crystal structure of PlGoxA reveals that it is a homotetramer.

Loss of ERα partially reverses the effects of maternal high-fat diet on energy homeostasis in female mice.

Maternal high-fat diet (HFD) alters hypothalamic developmental programming and disrupts offspring energy homeostasis in rodents. 17β-estradiol (E2) also influences hypothalamic programming through estrogen receptor (ER) α. Therefore, we hypothesized that females lacking ERα would be more susceptible to maternal HFD.

Interaction of 17β-estradiol and dietary fatty acids on energy and glucose homeostasis in female mice.

Fatty acid-induced hypothalamic inflammation (HI) is a potential cause of the obesity epidemic. It is unclear whether saturated or n-6 polyunsaturated fat is the primary driver of these effects. Premenopausal women are protected, in part, from obesity and associated comorbidities by circulating 17β-estradiol (E2).

Linoleic acid causes greater weight gain than saturated fat without hypothalamic inflammation in the male mouse.

A significant change in the Western diet, concurrent with the obesity epidemic, was a substitution of saturated fatty acids with polyunsaturated, specifically linoleic acid (LA). Despite increasing investigation on type as well as amount of fat, it is unclear which fatty acids are most obesogenic. The objective of this study was to determine the obesogenic potency of LA vs.

Regulation of arcuate genes by developmental exposures to endocrine-disrupting compounds in female rats.

Developmental exposure to endocrine-disrupting compounds (EDCs) alters reproduction and energy homeostasis, both of which are regulated by the arcuate nucleus (ARC). Little is known about the effects of EDC on ARC gene expression. In Experiment #1, pregnant dams were treated with either two doses of bisphenol A (BPA) or oil from embryonic day (E)18-21.

Regulation of gene expression by 17β-estradiol in the arcuate nucleus of the mouse through ERE-dependent and ERE-independent mechanisms.

17β-Estradiol (E2) modulates gene expression in the hypothalamic arcuate nucleus (ARC) to control homeostatic functions. In the ARC, estrogen receptor (ER) α is highly expressed and is an important contributor to E2's actions, controlling gene expression through estrogen response element (ERE)-dependent and -independent mechanisms. The objective of this study was to determine if known E2-regulated genes are regulated through these mechanisms.

Differential gene regulation of GHSR signaling pathway in the arcuate nucleus and NPY neurons by fasting, diet-induced obesity, and 17β-estradiol.

Ghrelin's receptor, growth hormone secretagogue receptor (GHSR), is highly expressed in the arcuate nucleus (ARC) and in neuropeptide Y (NPY) neurons. Fasting, diet-induced obesity (DIO), and 17β-estradiol (E2) influence ARC Ghsr expression. It is unknown if these effects occur in NPY neurons.

Estrogen response element-independent signaling partially restores post-ovariectomy body weight gain but is not sufficient for 17β-estradiol's control of energy homeostasis.

The steroid 17β-estradiol (E2) modulates energy homeostasis by reducing feeding behavior and increasing energy expenditure primarily through estrogen receptor α (ERα)-mediated mechanisms. Intact ERαKO female mice develop obesity as adults exhibiting decreased energy expenditure and increased fat deposition. However, intact transgenic female mice expressing a DNA-binding-deficient ERα (KIKO) are not obese and have similar energy expenditure, activity and fat deposition as to wild type (WT) females, suggesting that non-estrogen response element (ERE)-mediated signaling is important in E2 regulation of energy homeostasis.