The structure of rabbit muscle phosphoglucomutase at intermediate resolution.

Lin, Zheng‐Zhe; Konno, Masae; Abad‐Zapatero, Celerino; Wierenga, R.K.; Murthy, M.R.N.; Ray, William J.; Rossmann, Michael G.

doi:10.1016/s0021-9258(17)42464-1

Cited by 25 publications

(7 citation statements)

References 31 publications

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“…5301; Figure ), which might account for tetramers made up of two BPGM dimers. Dimeric structure of phosphoglucomutase 2 has been already reported in rabbit muscles and human RBCs (band 6, F2).…”

Section: Discussionmentioning

confidence: 99%

Native Protein Complexes in the Cytoplasm of Red Blood Cells

et al. 2013

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Despite decades of advancements, the investigation of the red blood cell (RBC) cytosolic proteome still represents a challenging task because of the overwhelming abundance of hemoglobin. Besides, the separation method is one of the main limiting factors when investigating protein complexes. In this study, we performed for the first time a 2D-clear native (CN)-SDS-PAGE followed by mass spectrometry-based identification to screen multiprotein complexes (MCPs) in the cytosol of human RBCs. Upstream to 2D-CN-SDS-PAGE, we applied a recently developed native pre-enrichment strategy that allows discriminating and separately collecting three distinct fractions, one of which is highly enriched for hemoglobin. Such prefractionation strategy is conservative, in that it makes soluble native-complex analyses amenable without loss of biological information. Because of the resolution of native gel electrophoresis techniques, we could observe and describe 55 potential hetero-oligomeric MPCs from the RBC native cytosolic proteome, among which ultratetrameric hemoglobin. The detected protein complexes were characterized by proteins mainly involved in oxygen transport, antioxidant responses, metabolism, and protein degradation cascades, in agreement with recent in silico models. Metabolic enzyme oligomers also interacted with complexes of proteins involved in oxidative stress responses, thus suggesting a functional relationship between metabolic modulation and antioxidant defenses.

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Section: Discussionmentioning

confidence: 99%

Native Protein Complexes in the Cytoplasm of Red Blood Cells

et al. 2013

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“…In each of the above cases, X-ray diffraction studies were conducted to show that the integrity of the crystal had not been adversely affected by the desalting procedure. In all cases outlined in Scheme I, the resolution of the diffraction pattern extended at least as far as for untreated crystals, where a large majority of the possible reflections with interplanar spacings of approximately 2.7 Á are measurable, and almost none with spacings smaller than 2.5 Á (Lin et al, 1986). For some crystals, a series of diffraction patterns consisting of 10-30 adjacent "frames" were measured with a Siemens X-ray area-detector system and an oscillation angle of 0.05-0.15°p er frame.…”

Section: Resultsmentioning

confidence: 92%

“…In these calculations, the estimate for the nonprotein volume was obtained by the procedure of Matthews (1968) based on a value of 3.12 for VM [cf. Lin et al (1986)]. Furthermore, we assumed that Glc-l-P was uniformly distributed throughout the nonprotein volume and that this volume is entirely accessible, as implied by the second experiment.…”

Section: Resultsmentioning

confidence: 99%

“…Crystals of rabbit muscle phosphoglucomutase were grown in the manner described previously (Lin et al, 1986) by vapor diffusion from a solution of the enzyme in aqueous 45-48% saturated (NH4)2S04, 4.2-4.5% (w/v) PEG-400, and 15 mM Mg2+, buffered at an apparent pH3 *of 6.5 with 50 mM MES. After being harvested, the crystals were transferred in 30 steps of equal increments (see below) from mother liquor to "storage solution": 2.3 M (NH4)2SG4, 50 mM MES, apparent pH 6.5, 16 mM Mg2+, and 1 mM EDTA.3 Unless otherwise stated, 1 Abbreviations: Glc-l-P, -D-glucose 1-phosphate; Glc-P2, a-Dglucose 1,6-bisphosphate; PEG, polyoxyethylene, or polyethylene glycol); HEPES, Af-(2-hydroxyethyl)piperazine-A-2-ethanesulfonic acid; MES, 2-(/V-morpholino)ethanesulfonic acid; a, activity, FWHM, full width at half-maximum height.…”

Section: Methodsmentioning

confidence: 99%

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Removal of salt from a salt-induced protein crystal without cross-linking. Preliminary examination of "desalted" crystals of phosphoglucomutase by x-ray crystallography at low temperature

Ray¹,

Bolin²,

Puvathingal³

et al. 1991

Biochemistry

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A model procedure for removing salt from relatively fragile salt-induced protein crystals is proposed. The procedure is based on physical principles and is validated by using millimeter-size crystals of rabbit muscle phosphoglucomutase grown from a 2.1 M solution of ammonium sulfate. Three types of operations are included in the procedure: initial transfer to salt solutions of reduced concentration; transfer to the organic-rich phase of an equilibrium biphasic mixture obtained with aqueous solutions of polyoxyethylene and the salt; and addition of various replacement cosolutes in aqueous solutions of polyoxyethylene to reduce osmotic stress on the crystal as the remaining salt is removed. A critical feature of the overall procedure is maintenance of near equilibrium throughout by using a large number of steps involving small changes in solute concentration. The conditions used in the actual transfer were adjusted to eliminate the fracturing of crystals by visually distinguishing between two opposing types of fracture patterns: those produced by osmotic crushing as opposed to osmotic expansion. Basic requirements for a successful procedure with other protein crystals are a high permeability toward small solutes and a relatively slow dissolution rate at salt concentrations for which biphasic mixtures can be obtained. Desalted crystals of phosphoglucomutase have no visible fractures, are stable in the final solution for at least a week, and exhibit no noticeable change in the resolution of their X-ray diffraction pattern. In fact, desalted crystals can be rapidly cooled to 160 K, whereas untreated crystals are almost completely disordered by the same cooling procedure. The component of the desalting mixture whose presence is crucial to the success of the cooling process is polyoxyethylene, which apparently impedes the formation of ice within the protein crystal. Diffraction data obtained with an area-detector diffractometer did not differ significantly, either in terms of quality or resolution range, between crystals in 2.3 M ammonium sulfate at room temperature and crystals at 160 K in which ammonium sulfate had been replaced by glycine. The successful use of the following replacement solutes, instead of glycine, also is documented: sucrose, glycerol, and a low molecular weight poly(ethylene glycol) (PEG-400).

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“…Friend leukemia virus integration 1 (FLI1), an ETS transcription factor family member that acts as an oncogenic driver in hematological malignancies was found to enhance the invasiveness of breast cancer cells (MDA-MDB 231) by binding to the FLI1 promoter and recruiting TET1 (demethylase), thereby regulating DNA demethylation (Chen N. et al, 2018). Studies show that circRNAs like circZNF609, circFBXw7, circPiNT exon-2, and circSHPRH regulate tumor growth and act as a tumor promoter by producing functional proteins through template translation (Lin et al, 1986;Yang et al, 2018). CircFBXW7 contains an open reading frame with IRES that facilitates cap-independent translation (Yang et al, 2018).…”

Section: Functional Role Of Circrnas With Special Emphasis On Circrna...mentioning

confidence: 99%

Insights Into the Role of CircRNAs: Biogenesis, Characterization, Functional, and Clinical Impact in Human Malignancies

Nisar

Bhat

Singh

et al. 2021

Front. Cell Dev. Biol.

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Circular RNAs (circRNAs) are an evolutionarily conserved novel class of non-coding endogenous RNAs (ncRNAs) found in the eukaryotic transcriptome, originally believed to be aberrant RNA splicing by-products with decreased functionality. However, recent advances in high-throughput genomic technology have allowed circRNAs to be characterized in detail and revealed their role in controlling various biological and molecular processes, the most essential being gene regulation. Because of the structural stability, high expression, availability of microRNA (miRNA) binding sites and tissue-specific expression, circRNAs have become hot topic of research in RNA biology. Compared to the linear RNA, circRNAs are produced differentially by backsplicing exons or lariat introns from a pre-messenger RNA (mRNA) forming a covalently closed loop structure missing 3′ poly-(A) tail or 5′ cap, rendering them immune to exonuclease-mediated degradation. Emerging research has identified multifaceted roles of circRNAs as miRNA and RNA binding protein (RBP) sponges and transcription, translation, and splicing event regulators. CircRNAs have been involved in many human illnesses, including cancer and neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease, due to their aberrant expression in different pathological conditions. The functional versatility exhibited by circRNAs enables them to serve as potential diagnostic or predictive biomarkers for various diseases. This review discusses the properties, characterization, profiling, and the diverse molecular mechanisms of circRNAs and their use as potential therapeutic targets in different human malignancies.

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The structure of rabbit muscle phosphoglucomutase at intermediate resolution.

Cited by 25 publications

References 31 publications

Native Protein Complexes in the Cytoplasm of Red Blood Cells

Native Protein Complexes in the Cytoplasm of Red Blood Cells

Removal of salt from a salt-induced protein crystal without cross-linking. Preliminary examination of "desalted" crystals of phosphoglucomutase by x-ray crystallography at low temperature

Insights Into the Role of CircRNAs: Biogenesis, Characterization, Functional, and Clinical Impact in Human Malignancies

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