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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reaction of various primary amines with acetylenic esters at ambient temperature in THF/H(2)O (50:50) produced related enaminones. Subsequently reaction of these in situ prepared enaminones with dibenzoylacetylene leads to 3-alkylidene-2,3-dihydro-1H-pyrrol-2-ol derivatives in good yields. The reaction of these products with various alcohols in the presence of a catalytic amount of HCl produced highly functionalized pyrroles in nearly quantitative yields.
Mol Divers 2007 Feb
PMID:A simple approach to the synthesis of highly functionalized 3-alkylidene-2,3-dihydro-1H-pyrrole-2-ol derivatives and related pyrroles. 1740 99

Solid complexes of lanthanide nitrate with 1,4-di(N,N-di-n-butyl-acetamido)-quinoxaline-2,3-dione (L), [Ln(N03)3L.H2O] (Ln=La, Nd, Eu, Gd, Tb, Er), have been prepared and characterized by elemental analysis, IR, UV-vis spectra and conductivity measurements. The fluorescence property of the europium complex in solid state and in MeCN, acetone, AcOEt and THF was studied. Under the excitation, the europium complex exhibited characteristic emissions of europium. The result indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion.
Spectrochim Acta A Mol Biomol Spectrosc 2007 Nov
PMID:Synthesis and spectroscopic properties of lanthanide nitrate complexes with a new amide-based quinoxaline-2,3-dione ligand. 1741 93

The carbanionic species possibly formed during the first alkylation step of phenylacetonitrile lithiated anion by CH(3)I and PhCH(2)Cl in THF-hexane solution and their complexes with the lithium salt formed have been observed by infrared spectrometry and characterized by density functional theory calculations. The spectra of alkylated phenylacetonitrile lithiated anion monomers and dimers have been identified in good agreement with calculations. The wave numbers of the vibrational modes of the alkylated species differ significantly from those of PhCHCNLi species, but do not depend appreciably on the substituent nature. Nevertheless with the methyl substituent, the isomerization equilibrium of the monomer is noticeably shifted toward the bridged (C-lithiated) species. The formation of a heterodimer at the expense of the dimer after addition of LiCl has been confirmed by experiment.
Spectrochim Acta A Mol Biomol Spectrosc 2007 Dec 31
PMID:Identification of the monoanions and of their complexes with lithium salts possibly formed in solution during the alkylation of lithiated phenylacetonitrile dianions: infrared spectroscopy and density functional theory calculations. 1746 72

Cystathionine beta synthase (CBS) deficiency is a metabolic disorder that is biochemically characterized by severe hyperhomocysteinemia. In order to show the effects of CBS deficiency onto the activity of the enzymes involved in the remethylation pathway, we used the well characterized genetic model of severe hyperhomocysteinemia in mice. We showed that CBS deficiency in mice reduced hepatic methionine synthase and betaine-homocysteine methyltransferase activities, whereas 5,10-methylene tetrahydrofolate reductase activity was increased.
Mol Genet Metab 2007 Aug
PMID:Mice deficient in cystathionine beta synthase display altered homocysteine remethylation pathway. 1756 77

In situ Raman and Fourier transform infrared (FTIR-NIR) spectroscopic studies on tetrahydrofuran (THF-C(4)H(8)O) clathrate hydrate (CH) were reported. The Raman results in lattice (64 cm(-1)), ring breathing and C-H stretching mode regions are in conformity with earlier reports, while the FTIR (NIR) studies in second order mode region were reported for the first time. Comparison of the results indicate that the band assigned to ring breathing mode around 922 cm(-1) (in Raman) and corresponding second order mode in NIR around 4295 cm(-1) broadens and shifts in enclathrated THF. The ring breathing mode at lower temperatures (T<120 K) is highly asymmetric and splits into two and are due to different host-guest interactions at lower temperatures.
Spectrochim Acta A Mol Biomol Spectrosc 2007 Dec 15
PMID:Laser Raman spectroscopy of THF clathrate hydrate in the temperature range 90-300 K. 1772 76

Escherichia coli dihydrofolate reductase (DHFR) catalyzes the reduction of dihydrofolate to tetrahydrofolate. During the catalytic cycle, DHFR undergoes conformational transitions between the closed (CS) and occluded (OS) states that, respectively, describe whether the active site is closed or occluded by the Met20 loop. The CS-->OS and the reverse transition may be viewed as allosteric transitions. Using a sequence-based approach, we identify a network of residues that represents the allostery wiring diagram. Many of the residues in the allostery wiring diagram, which are dispersed throughout the adenosine-binding domain as well as the loop domain, are not conserved. Several of the residues in the network have been previously shown by NMR experiments, mutational studies, and molecular dynamics simulations to be linked to equilibration conformational fluctuations of DHFR. To further probe the nature of events that occur during conformational fluctuations, we use a self-organized polymer model to monitor the kinetics of the CS-->OS and the reverse transitions. During the CS-->OS transition, coordinated changes in a number of residues in the loop domain enable the Met20 loop to slide along the alpha-helix in the adenosine-binding domain. Sliding is triggered by pulling of the Met20 loop by the betaG-betaH loop and the pushing action of the betaG-betaH loop. The residues that facilitate the Met20 loop motion are part of the network of residues that transmit allosteric signals during the CS-->OS transition. Replacement of M16 and G121, whose C(alpha) atoms are about 4.3 A in the CS, by a disulfide cross-link impedes that CS-->OS transition. The order of events in the OS-->CS transition is not the reverse of the forward transition. The contact Glu18-Ser49 in the OS persists until the sliding of the Met20 loop is nearly complete. The ensemble of structures in the transition state in both the allosteric transitions is heterogeneous. The most probable transition-state structure resembles the OS (CS) in the CS-->OS (OS-->CS) transition, which is in accord with the Hammond postulate. Structures resembling the OS (CS) are present as minor ( approximately 1-3%) components in equilibrated CS (OS) structures.
J Mol Biol 2007 Nov 16
PMID:Allosteric communication in dihydrofolate reductase: signaling network and pathways for closed to occluded transition and back. 1791 64

A genome-wide screen for Saccharomyces cerevisiae iron-sulfur (Fe/S) cluster assembly mutants identified the gene IBA57. The encoded protein Iba57p is located in the mitochondrial matrix and is essential for mitochondrial DNA maintenance. The growth phenotypes of an iba57Delta mutant and extensive functional studies in vivo and in vitro indicate a specific role for Iba57p in the maturation of mitochondrial aconitase-type and radical SAM Fe/S proteins (biotin and lipoic acid synthases). Maturation of other Fe/S proteins occurred normally in the absence of Iba57p. These observations identify Iba57p as a novel dedicated maturation factor with specificity for a subset of Fe/S proteins. The Iba57p primary sequence is distinct from any known Fe/S assembly factor but is similar to certain tetrahydrofolate-binding enzymes, adding a surprising new function to this protein family. Iba57p physically interacts with the mitochondrial ISC assembly components Isa1p and Isa2p. Since all three proteins are conserved in eukaryotes and bacteria, the specificity of the Iba57/Isa complex may represent a biosynthetic concept that is universally used in nature. In keeping with this idea, the human IBA57 homolog C1orf69 complements the iba57Delta growth defects, demonstrating its conserved function throughout the eukaryotic kingdom.
Mol Cell Biol 2008 Mar
PMID:Mitochondrial Iba57p is required for Fe/S cluster formation on aconitase and activation of radical SAM enzymes. 1808 97

Preferential solvation of fluorenone (9Fl) and 4-hydroxyfluorenone (4HOFl) in binary solvent mixtures (cyclohexane-tetrahydrofuran (CH-THF) and cyclohexane-ethanol (CH-EtOH)) has been studied using steady-state spectroscopic measurements. The solvation of the fluorenones, both in the ground and in the excited states, exhibits a non-linear solvatochromic shifts as a function of polar component in the binary solvent mixtures. The results of spectroscopic measurements were used to calculate, according to Bakhshiev's and Kiselev's theory, the fluorescence spectra of solvates having different number of polar component in the first solvation shell. The different features of fluorescence spectra of molecule under study in CH-THF and CH-EtOH are explained by the absence and presence of specific solute-solvent interactions (hydrogen bond).
Spectrochim Acta A Mol Biomol Spectrosc 2008 Nov 15
PMID:Spectroscopic determination of solvation shell composition of fluorenone and 4-hydroxyfluorenone in binary solvent mixtures. 1828 37

This article mainly reviews hypercoagulability--and specifically inherited thrombophilia--in different types of surgery including kidney transplantation, simultaneous kidney and pancreas transplantation, orthopedic surgery, vascular surgery, cardiac surgery and other categories of surgical procedures, with a major focus on its associated complications and the need to screen or not. A search was conducted using Medline and cross-referencing for articles related to thrombophilia, screening for it, and its association with surgical complications post-op. Thrombosis associated predisposing entities like factor V Leiden, Prothrombin and Methylene tetrahydrofolate reductase gene mutations, in addition to Protein C and S deficiencies, are discussed. In addition, common and relatively uncommon complications of thrombophilia in the above mentioned surgeries will be covered in length, as well as the necessity to screen for thrombophilia prior to the surgical step. This topic is gaining more and more importance for both surgeons and internists (especially Hematologists) and we, herein, present a general review of the published literature as an update on the subject.
Mol Biol Rep 2009 May
PMID:The impact of inherited thrombophilia on surgery: a factor to consider before transplantation? 1851 2

The loss of the ability to deaminate l-serine severely impairs growth and cell division in Escherichia coli K-12. A strain from which the three genes (sdaA, sdaB, tdcG) coding for this organism's three l-serine deaminases had been deleted grows well in glucose minimal medium but, on subculture into minimal medium with glucose and casamino acids, it makes very large, abnormally shaped cells, many of which lyse. When inoculated into Luria-Bertani (LB) broth with or without glucose, it makes very long filaments. Provision of S-adenosylmethionine restores cell division in LB broth with glucose, and repairs much of the difficulty in growth in medium with casamino acids. We suggest that replication of E. coli is regulated by methylation, that an unusually high intracellular l-serine concentration, in the presence of other amino acids, starves the cell for S-adenosylmethionine and that it is the absence of S-adenosylmethionine and/or of C1-tetrahydrofolate derivatives that prevents normal cell division.
Mol Microbiol 2008 Aug
PMID:Deficiency in l-serine deaminase results in abnormal growth and cell division of Escherichia coli K-12. 1853 81


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