Interplay of Structural Disorder and Short Binding Elements in the Cellular Chaperone Function of Plant Dehydrin ERD14.

Details of the functional mechanisms of intrinsically disordered proteins (IDPs) in living cells is an area not frequently investigated. Here, we dissect the molecular mechanism of action of an IDP in cells by detailed structural analyses based on an in-cell nuclear magnetic resonance experiment. We show that the ID stress protein (IDSP) A. thaliana Early Response to Dehydration (ERD14) is capable of protecting E. coli cells under heat stress. The overexpression of ERD14 increases the viability of E. coli cells from 38.9% to 73.9% following heat stress (50 °C × 15 min). We also provide evidence that the protection is mainly achieved by protecting the proteome of the cells. In-cell NMR experiments performed in E. coli cells show that the protective activity is associated with a largely disordered structural state with conserved, short sequence motifs (K- and H-segments), which transiently sample helical conformations in vitro and engage in partner binding in vivo. Other regions of the protein, such as its S segment and its regions linking and flanking the binding motifs, remain unbound and disordered in the cell. Our data suggest that the cellular function of ERD14 is compatible with its residual structural disorder in vivo

Quantification of Intrinsically Disordered Proteins: A Problem Not Fully Appreciated

Protein quantification is essential in a great variety of biochemical assays, yet the inherent systematic errors associated with the concentration determination of intrinsically disordered proteins (IDPs) using classical methods are hardly appreciated. Routinely used assays for protein quantification, such as the Bradford assay or ultraviolet absorbance at 280 nm, usually seriously misestimate the concentrations of IDPs due to their distinct and variable amino acid composition. Therefore, dependable method(s) have to be worked out/adopted for this task. By comparison to elemental analysis as the gold standard, we show through the example of four globular proteins and nine IDPs that the ninhydrin assay and the commercial Qubit(TM) Protein Assay provide reliable data on IDP quantity. However, as IDPs can show extreme variation in amino acid composition and physical features not necessarily covered by our examples, even these techniques should only be used for IDPs following standardization. The far-reaching implications of these simple observations are demonstrated through two examples: (i) circular dichroism spectrum deconvolution, and (ii) receptor-ligand affinity determination. These actual comparative examples illustrate the potential errors that can be incorporated into the biophysical parameters of IDPs, due to systematic misestimation of their concentration. This leads to inaccurate description of IDP functions

Quantification of Intrinsically Disordered Proteins: A Problem Not Fully Appreciated

Protein quantification is essential in a great variety of biochemical assays, yet the inherent systematic errors associated with the concentration determination of intrinsically disordered proteins (IDPs) using classical methods are hardly appreciated. Routinely used assays for protein quantification, such as the Bradford assay or ultraviolet absorbance at 280 nm, usually seriously misestimate the concentrations of IDPs due to their distinct and variable amino acid composition. Therefore, dependable method(s) have to be worked out/adopted for this task. By comparison to elemental analysis as the gold standard, we show through the example of four globular proteins and nine IDPs that the ninhydrin assay and the commercial QubitTM Protein Assay provide reliable data on IDP quantity. However, as IDPs can show extreme variation in amino acid composition and physical features not necessarily covered by our examples, even these techniques should only be used for IDPs following standardization. The far-reaching implications of these simple observations are demonstrated through two examples: (i) circular dichroism spectrum deconvolution, and (ii) receptor-ligand affinity determination. These actual comparative examples illustrate the potential errors that can be incorporated into the biophysical parameters of IDPs, due to systematic misestimation of their concentration. This leads to inaccurate description of IDP functions

Case Report of Advanced Juvenile Nasopharyngeal Angiofibroma with Cavernous Sinus Involvement: Advantages of Advanced Radiotherapy Thechnique Volumetric Modulated Arc Therapy

Objectives: In very advance unresectable stages Juvenile nasopharyngeal angiofibroma (JNA)radiotherapy is treatment of choice. Usually JNA is in close proximity to different organ at risk, which necessitates accurate and precise radiation delivery. Series reported the application of IMRT (Intensity Modulated Radiotherapy) with good sparing of organ at risk, but the literature search found no report on VMAT (Volumetric Modulated Arc Therapy) treatment in case of JNA.Clinical case: The present publication report for first time a patient irradiated with VMAT and IGRT (Image guided radiotherapy) for JNA. The stage of the tumor based on CT and MRI was IIIB according to Radkovsi with cavernous sinus invasion. Moderate total radiation dose 36 Gy in 1.8 Gy per fraction was delivered. No early and late toxicity was recorded. The patient is followed up every six months and persistent residual tumor on MRI was seen, but no bleeding onphysical exam. At one year follow up this is accepted as good local control.Conclusion: VMAT and IGRT could be safely applied with reduction of the radiation dose at organ of risk. VMAT is promising in the treatment of juvenile angiofibroma with advantages over conventional radiotherapy, but as this is case report of only one patient, further experience with VMAT is needed in JN

Elemental Composition of Infusions of Herbs (Tisanes) of North Ossetia (the Caucasus)

Herbal infusions are consumed worldwide owing to their beneficial properties. Cultivated or obtained from the wild, herbal raw plant materials may contain trace elements at various levels. This study relates to the release of beneficial and potentially toxic trace elements from herbal preparations during infusion. The elemental contents of seven commercially available herbal tea products were determined prior to and following two modes of infusion. Teabags (of equal herb content) were infused in 200 mL of boiling bottled water “Holy Spirit” for 15 and 45 min, in glass beakers. The total content of 57 elements including heavy metals, rare earth elements, as well as Th and U, were determined by ICP-MS and ICP-AES. The metals present in the highest concentrations were K, Ca, P, and S. Potassium, Mg, Co, Ni, As, Rb, and Cs had the highest extractability, whereas Ga, Ge, Se, Zr, Nb, Te, Er, Yb, W, Tl, and U had the lowest extractability

Interplay of Structural Disorder and Short Binding Elements in the Cellular Chaperone Function of Plant Dehydrin ERD14.

Details of the functional mechanisms of intrinsically disordered proteins (IDPs) in living cells is an area not frequently investigated. Here, we dissect the molecular mechanism of action of an IDP in cells by detailed structural analyses based on an in-cell nuclear magnetic resonance experiment. We show that the ID stress protein (IDSP) A. thaliana Early Response to Dehydration (ERD14) is capable of protecting E. coli cells under heat stress. The overexpression of ERD14 increases the viability of E. coli cells from 38.9% to 73.9% following heat stress (50 °C × 15 min). We also provide evidence that the protection is mainly achieved by protecting the proteome of the cells. In-cell NMR experiments performed in E. coli cells show that the protective activity is associated with a largely disordered structural state with conserved, short sequence motifs (K- and H-segments), which transiently sample helical conformations in vitro and engage in partner binding in vivo. Other regions of the protein, such as its S segment and its regions linking and flanking the binding motifs, remain unbound and disordered in the cell. Our data suggest that the cellular function of ERD14 is compatible with its residual structural disorder in vivo

A holistic approach to resurrection plants. Haberlea rhodopensis. – A case study

Recent environmental changes challenge world agriculture and reconfirm the importance of wild flora as useful source of valuable traits. Due to their extreme desiccation tolerance, the so called Resurrection plants are extensively studied and characterized. The Bulgarian endemic species Haberlea rhodopensis, apart from its typical resurrection capacity is very interesting also as a potential source of bioactive compounds with putative application in pharmacology, veterinary medicine and cosmetics. Here we discuss our approaches to Haberlea in the frames of the NSF funded project DO02-105 Centre for sustainable development of plant and animal genomics.status: publishe

Treatment of Childhood Acute Myeloid Leukemia in Bulgaria

Background: During the last four decades the prognosis of childhood acute myeloid leukemia (AML) has been substantially improved due to an increase in complete remission (CR) rates, event-free survival (EFS) and reduced early mortality. The relapsed AML still remains a therapeutic challenge

Interplay of Structural Disorder and Short Binding Elements in the Cellular Chaperone Function of Plant Dehydrin ERD14

Details of the functional mechanisms of intrinsically disordered proteins (IDPs) in living cells is an area not frequently investigated. Here, we dissect the molecular mechanism of action of an IDP in cells by detailed structural analyses based on an in-cell nuclear magnetic resonance experiment. We show that the ID stress protein (IDSP) A. thaliana Early Response to Dehydration (ERD14) is capable of protecting E. coli cells under heat stress. The overexpression of ERD14 increases the viability of E. coli cells from 38.9% to 73.9% following heat stress (50 °C × 15 min). We also provide evidence that the protection is mainly achieved by protecting the proteome of the cells. In-cell NMR experiments performed in E. coli cells show that the protective activity is associated with a largely disordered structural state with conserved, short sequence motifs (K- and H-segments), which transiently sample helical conformations in vitro and engage in partner binding in vivo. Other regions of the protein, such as its S segment and its regions linking and flanking the binding motifs, remain unbound and disordered in the cell. Our data suggest that the cellular function of ERD14 is compatible with its residual structural disorder in viv