Refinement of protein Fe(II) binding characteristics utilizing a competition assay exploiting small molecule ferrous chelators.

Iron is the most prevalent metal in biology. Its chemical and redox versatility allows it to direct activity of many Fe binding proteins. While iron's biological applications are diverse, challenges inherent in having Fe(II) present at high abundance means cells must ensure delivery to the correct recipient, while also ensuring its chemistry is regulated. Having a detailed understanding of the biophysical characteristics of a protein's iron binding characteristics allows us to understand general cellular metal homeostasis events. Unfortunately, most spectroscopic techniques available to measure metal binding affinity require protein be in a homogeneous state. Homogeneity creates an artificial environment when measuring metal binding since within cells numerous additional metal binding biomolecules compete with the target. Here we investigate commercially available Fe(II) chelators with spectral markers coupled to metal binding and release. Our goal was to determine their utility as competitors while measuring aspects of metal binding by apoproteins during a metal binding competition assay. Adding chelators during apoprotein metal binding mimics heterogeneous metal binding environments present in vivo, and provides a more realistic metal binding affinity measurement. Ferrous chelators explored within this report include: Rhod-5N, Magfura-2, Fura-4F, Fura-2, and TPA (Tris-(2-byridyl-methyl)amine; each forms a 1:1 complex with Fe(II) and combined cover a binding range of 5 orders of magnitude (micromolar to nanomolar Kd). These chelators were used to calibrate binding affinities for yeast and fly frataxin (Yfh1 and Dfh, respectively), involved in mitochondrial FeS cluster bioassembly.

Great expectations: using an analysis of current practices to propose a framework for the undergraduate inorganic curriculum.

The undergraduate inorganic chemistry curriculum in the United States mirrors the broad diversity of the inorganic research community and poses a challenge for the development of a coherent curriculum that is thorough, rigorous, and engaging. A recent large survey of the inorganic community has provided information about the current organization and content of the inorganic curriculum from an institutional level. The data reveal shared "core" concepts that are broadly taught, with tremendous variation in content coverage beyond these central ideas. The data provide an opportunity for a community-driven discussion about how the American Chemical Society's Committee on Professional Training's vision of a foundation and in-depth course for each of the five subdisciplines maps onto an inorganic chemistry curriculum that is consistent in its coverage of the core inorganic concepts, yet reflects the diversity and creativity of the inorganic community. The goal of this Viewpoint is to present the current state of the diverse undergraduate curriculum and lay a framework for an effective and engaging curriculum that illustrates the essential role inorganic chemistry plays within the chemistry community.

Inorganic chemistry and IONiC: an online community bringing cutting-edge research into the classroom.

This Viewpoint highlights creative ways that members of the Interactive Online Network of Inorganic Chemists (IONiC) are using journal articles from Inorganic Chemistry to engage undergraduate students in the classroom. We provide information about specific educational materials and networking features available free of charge to the inorganic community on IONiC's web home, the Virtual Inorganic Pedagogical Electronic Resource (VIPEr, www.ionicviper.org ) and describe the benefits of joining this community.

Cancer pharmacogenomics and pharmacoepidemiology: setting a research agenda to accelerate translation.

Recent advances in genomic research have demonstrated a substantial role for genomic factors in predicting response to cancer therapies. Researchers in the fields of cancer pharmacogenomics and pharmacoepidemiology seek to understand why individuals respond differently to drug therapy, in terms of both adverse effects and treatment efficacy. To identify research priorities as well as the resources and infrastructure needed to advance these fields, the National Cancer Institute (NCI) sponsored a workshop titled "Cancer Pharmacogenomics: Setting a Research Agenda to Accelerate Translation" on July 21, 2009, in Bethesda, MD. In this commentary, we summarize and discuss five science-based recommendations and four infrastructure-based recommendations that were identified as a result of discussions held during this workshop. Key recommendations include 1) supporting the routine collection of germline and tumor biospecimens in NCI-sponsored clinical trials and in some observational and population-based studies; 2) incorporating pharmacogenomic markers into clinical trials; 3) addressing the ethical, legal, social, and biospecimen- and data-sharing implications of pharmacogenomic and pharmacoepidemiologic research; and 4) establishing partnerships across NCI, with other federal agencies, and with industry. Together, these recommendations will facilitate the discovery and validation of clinical, sociodemographic, lifestyle, and genomic markers related to cancer treatment response and adverse events, and they will improve both the speed and efficiency by which new pharmacogenomic and pharmacoepidemiologic information is translated into clinical practice.

Blood pressure and bone mineral density in premenopausal and postmenopausal women.

INTRODUCTION: Previous studies regarding the associations between blood pressure (BP) and bone mineral density (BMD) have shown conflicting results. However, menopausal status and pharmacotherapy may modify this relationship. The objective of this study was to explore the association between systolic BP (SBP) and diastolic BP (DBP) and BMD in pre- and postmenopausal women, and to assess the extent to which this association is mediated by menopausal status and pharmacotherapy. METHODS: A cross-sectional study was conducted using a sample of 4,058 pre- and postmenopausal women aged 40 years or older (N = 991 and 3,067, respectively), who participated in NHANES III. BMD measurement of the femur neck was used as the primary outcome measure. Regression models were used to examine the association between SBP or DBP and BMD. RESULTS: The unadjusted models for systolic and diastolic BP were positively and significantly associated with femoral BMD in premenopausal women (p = 0.0039 and p = 0.0065, respectively) as well as in postmenopausal women (p < 0.0001 for both SBP and DBP). After adjusting for covariates in the multivariate models, the association between BP and BMD in postmenopausal women no longer prevailed. In premenopausal women, the association between SBP or DBP and BMD was modified by hormone therapy (p = 0.0278 and p = 0.0025, respectively). Once the stratum-specific adjusted models by hormone therapy use were examined, the association between SBP or DBP and BMD was no longer significant. CONCLUSIONS: The study results suggest that there is no link between BP and BMD in pre- and postmenopausal women.

Gastroenterologists' prescribing of infliximab for Crohn's disease: a national survey.

BACKGROUND: Practice guidelines suggest that immunomodulators (IMs) be given prior to infliximab (IFX) in patients with Crohn's disease (CD). The package insert for IFX recommends that maintenance therapy be prescribed for patients who respond to induction therapy. Our aim was to determine the extent to which gastroenterologists (GIs) are utilizing IM prior to IFX and prescribing maintenance IFX when treating patients with CD. METHODS: An 18-item questionnaire was developed and validated. The survey was sent to 4515 GIs who are members of the American Gastroenterology Association. Bivariate and multivariate analyses were performed. RESULTS: In all, 305 GIs responded; 70% use an IM prior to IFX, 86% prescribe maintenance IFX, and 62% reported both use of IM prior to IFX and use of maintenance IFX. Academic GIs, Midwest GIs, and GIs prescribing IFX a few times per year were more likely to report both use of an IM prior to IFX and use of maintenance IFX (odds ratio [OR] = 4.56, 2.18, and 2.25, respectively). GIs demonstrated awareness of the risk of reactivation of tuberculosis when initiating IFX and appropriately manage infusion reactions. GIs were unable to rank serious adverse reactions associated with IFX. CONCLUSIONS: A total of 38% of GIs did not report the use of IM prior to IFX and/or did not use maintenance IFX. GIs practicing outside the Midwest and those in nonacademic settings may need additional training regarding prescribing IFX.

Investigation of the copper binding site and the role of histidine as a ligand in riboflavin binding protein.

Riboflavin Binding Protein (RBP) binds copper in a 1:1 molar ratio, forming a distinct well-ordered type II site. The nature of this site has been examined using X-ray absorption and pulsed electron paramagnetic resonance (EPR) spectroscopies, revealing a four coordinate oxygen/nitrogen rich environment. On the basis of analysis of the Cambridge Structural Database, the average protein bound copper-ligand bond length of 1.96 A, obtained by extended x-ray absorption fine structure (EXAFS), is consistent with four coordinate Cu(I) and Cu(II) models that utilize mixed oxygen and nitrogen ligand distributions. These data suggest a Cu-O 3N coordination state for copper bound to RBP. While pulsed EPR studies including hyperfine sublevel correlation spectroscopy and electron nuclear double resonance show clear spectroscopic evidence for a histidine bound to the copper, inclusion of a histidine in the EXAFS simulation did not lead to any significant improvement in the fit.

Association of Copper to Riboflavin Binding Protein; Characterization by EPR and XAS.

The association of copper to Riboflavin Binding Protein (RBP) from egg white has been studied by electron paramagnetic resonance (EPR) and X-ray absorption (XAS) spectroscopies. The type II site contains a mix of copper I and II in an oxygen rich environment.

Riboflavin binding protein contains a type II copper binding site.

Riboflavin binding protein, purified from egg white, binds copper(II) under dialysis conditions in an approximately 1:1 molar ratio. Results further indicate a small, but not negligible, amount of copper is present in the protein as purified from egg white. Electron paramagnetic resonance indicates a single type II copper site present in the protein. These results suggest the possibility of a previously unknown function of riboflavin binding protein in the storage or transport of copper.