Sodium 2-mercaptoethanesulfonate monohydrate (coenzyme M sodium salt monohydrate)

The 2-thio­ethanesulfonate anion is the smallest known coenzyme in nature (HS–CoM) and plays a key role in methano­genesis by anaerobic archaea, as well as in the oxidation of alkenes by Gram-negative and Gram-positive eubacteria. The title compound, Na+·C2H5O3S2 −·H2O, is the Na+ salt of HS–CoM crystallized as the monohydrate. Six O atoms form a distorted octa­hedral coordination geometry around the Na atom, at distances in the range 2.312 (4)–2.517 (3) Å. Two O atoms of the sulfonate group, one O atom of each of three other symmetry-related sulfonate groups plus the water O atom form the coordination environment of the Na+ ion. This arrangement forms Na–O–Na layers in the crystal structure, parallel to (100)

Self-assembly and two-dimensional spontaneous resolution of cyano-functionalized [7]helicenes on Cu111

Birds of a feather flock together: STM and DFT studies provide the first example of spontaneous chiral resolution of a helicene on a surface. Racemic 6,13-dicyano[7]helicene forms fully segregated domains of pure enantiomers (2D conglomerate) on Cu(111). The propensity of the system to optimize intermolecular CN⋅⋅⋅HC(Ar) hydrogen bonding and CN⋅⋅⋅CN dipolar interactions translates into chiral recognition with preferential assembly of homochiral molecules

1028-63 Cardiac Troponin T as a Marker for Perioperative Myocardial Ischemia in Noncardiac Surgical Patients

Episodes of perioperative myocardial ischemia (PMI) occur in 18 to 74% of noncardiac surgical patients with or at risk for coronary artery disease (CAD). PMls correlate with adverse postoperative cardiac outcome. To determine the diagnostic value of cardiac troponin T(TnT) in PMI, we studied 28 patients (63.9±8.9 years) undergoing peripheral vascular surgery (n=16) or carotid endarterectomy (n=12). Patients included had either documented CAD (n=16) or two (n=7) or more (n=5) risk factors (age >65 years, smoking. diabetes mellitus. hypertension, or hypercholesterolemia >240 mg/dL). Patients with uninterpretable ECG for PMI were excluded. 12-lead ECG recordings and blood sampling for measurement of CK-MB activity and TnT levels (ELISA troponin 1. Boehringer Mannheim, Germany) were carried out preoperatively, and immediately, 20 h, 48 h, 72 h, and 84 h postoperatively. ECG recordings were analysed by an independent blinded cardiologist for signs of PMI (new ST segment depression >0.1 mV 60 ms after the J point, new T inversion). We found an overall incidence of ECG documented PMI of 54% (n=15), 93% occuring immediately postoperatively. Patients undergoing peripheral vascular surgery developed significantly less PMI than carotid surgical patients (38% vs. 75%; p<0.05, Fisher's Exact test). TnT levels >0.1 μg/L were found in 80% (n=12) of patients with PMI (ECG). Only one patient without ECG-documented PMI had TnT levels >0.1 μg/L. Thus, comparing a TnT cut off level of 0.1 μg/L with intermittent 12-lead ECG recording, we found a sensitivity of 80% and a specifity of 92%. We were unable to detect elevated levels of CK-MB in any patient (tab.).overall (n=28)per. vase. surg. (n=16)carotid surg. (n=12)CK-MB >6 U/L000ECG(PMI)15(54%)6 (38%)9(75%)TnT >0.1 μg/L13(46%)5(31%)8(67%)ConclusionIn contrast to CK-MB, TnT is a specific and sensitive marker of PMI in patients with or at risk for CAD undergoing noncardiac surgery

Frustrated H-Induced Instability of Mo(110)

Using helium atom scattering Hulpke and L"udecke recently observed a giant phonon anomaly for the hydrogen covered W(110) and Mo(110) surfaces. An explanation which is able to account for this and other experiments is still lacking. Below we present density-functional theory calculations of the atomic and electronic structure of the clean and hydrogen-covered Mo(110) surfaces. For the full adsorbate monolayer the calculations provide evidence for a strong Fermi surface nesting instability. This explains the observed anomalies and resolves the apparent inconsistencies of different experiments.Comment: 4 pages, 2 figures, submitted to PR

The Ustilago maydis Effector Pep1 Suppresses Plant Immunity by Inhibition of Host Peroxidase Activity

The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H2O2 strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction

Perfluorophenyl-Phenyl Interactions in the Crystallization and Topochemical Polymerization of Triacetylene Monomers

A series of symmetrically and unsymmetrically substituted octa-2,4,6-triyne-1,8-diol derivatives with benzoyl, 4-dodecyloxybenzoyl, as well as perfluorobenzoyl substituents were prepared and investigated with respect to their crystal structures and topochemical polymerizability. Single-crystal structures for several of these triacetylene monomers have been obtained and proved that the perfluoro-phenyl-phenyl interactions played a decisive role in the molecular packing. As a consequence of the geometric requirements imposed by the perfluoro-phenyl-phenyl interactions, packing parameters appropriate for a topochemical triacetylene polymerization in the sense of either a 1,6- or a 1,4-polyaddition along different crystallographic axes were observed in two cases, and UV irradiation led to successful polymerization. Raman as well as solid-state C-13 NMR spectra of the obtained polymers revealed that the polymerization had predominantly proceeded in the form of a 1,4-polyaddition

Stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants

A general strategy has been devised for the stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants thereof, which relies on late stage introduction of the heterocycle through Wittig olefination of ketone 14. Formation of the macrocycle was achieved through RCM-based ring closure and introduction of the cyclopropane moiety involved a highly selective Charette cyclopropanation of allylic alcohol 7

Optical stability of axially chiral push-pull-substituted buta-1,3dienes: Effect of a single methyl group on the C60 surface

A new spin on C60: Axially chiral, pushpull buta-1,3-diene chromophores conjugated to vicinally methylated fullerenes (see picture) have high barriers of rotation about their chiral axes. These high barriers allowed their optical resolution and the determination of the absolute configuration by comparison of experimental and calculated circular dichroism spectra. The methyl group is rigidly fixed upon the surface of the carbon sphere and is responsible for the high rotational barriers. (Figure Presented). © 2010 Wiley-VCH Verlag GmbH \& Co. KGaA