Search results for "Triad"

Structural Basis and Enzymatic Mechanism of the Biosynthesis of C9- from C10-Monoterpenoid Indole Alkaloids

2009

Cutting carbons: The three-dimensional structure of polyneuridine aldehyde esterase (PNAE) gives insight into the enzymatic mechanism of the biosynthesis of C(9)- from C(10)-monoterpenoid indole alkaloids (see scheme). PNAE is a very substrate-specific serine esterase. It harbors the catalytic triad S87-D216-H244, and is a new member of the alpha/beta-fold hydrolase superfamily. Its novel function leads to the diversification of alkaloid structures.

Rasgos de personalidad, bienestar y malestar psicológico en usuarios de redes sociales que presentan conductas disruptivas online

2021

The present study focused on the analysis of online disruptive behavior that usually occurs among social network users. Individuals who perpetrate such behavior are commonly known as trolls or haters (Cheng, Danescu-Niculescu-Mitzil, & Leskovec, 2015). In general, they post comments, photos or provocative videos that do not pursue any purpose other than annoying or obtaining pleasure or fun (Brandel, 2007; Phillips, 2011). Recent studies have shown that certain personality traits are associated with the presence of such disruptive behavior. In this research, we studied normal personality traits, psychopathological traits, and dark personality traits in relation to disruptive behavior. The n…

The triad approach for assessment of industrial contamination in freshwater sediments, Opole Region, Poland,

2007

Topological effects of a rigid chiral spacer on the electronic interactions in donor-acceptor ensembles

2005

Two triads (donor-spacer-acceptor), etTTF-BN-C 6 0 (6) and ZnP-BN-C 6 0 (7), in which electron donors (i.e., exTTF or ZnP) are covalently linked to C 6 0 through a chiral binaphthyl bridge (BN), have been prepared in a multistep synthetic procedure starting from a highly soluble enantiomerically pure binaphthyl building block (1). Unlike other oligomeric bridges, with hinaphthyl bridges, the conjugation between the donor and the acceptor units is broken and geometric conformational changes are facilitated. Consequently, distances and electronic interactions between the donor and C 6 0 are drastically changed. Both donor-spacer-acceptor (D-s-A) systems (i.e., 6 and 7) exhibit redox processes…

Potential active-site residues in polyneuridine aldehyde esterase, a central enzyme of indole alkaloid biosynthesis, by modelling and site-directed m…

2002

In the biosynthesis of the antiarrhythmic alkaloid ajmaline, polyneuridine aldehyde esterase (PNAE) catalyses a central reaction by transforming polyneuridine aldehyde into epi-vellosimine, which is the immediate precursor for the synthesis of the ajmalane skeleton. The PNAE cDNA was previously heterologously expressed in E. coli. Sequence alignments indicated that PNAE has a 43% identity to a hydroxynitrile lyase from Hevea brasiliensis, which is a member of the α/β hydrolase superfamily. The catalytic triad, which is typical for this family, is conserved. By site-directed mutagenesis, the members of the catalytic triad were identified. For further detection of the active residues, a model…

Copper-, cobalt-, and manganese-containing 17-tungsto-2-germanates.

2009

The sandwich-type tungstogermanates [Cu(3)(H(2)O)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))](12-) (1), [Co(H(2)O)(2){Co(3)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))}(2)](22-) (2), and [Mn(H(2)O)(2){Mn(3)(H(2)O)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))}(2)](22-) (3) were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and infrared spectroscopy. Polyanion 1 is composed of two nonequivalent Keggin units, (B-beta-GeW(8)O(31)) and (B-beta-GeW(9)O(34)), linked to each other via three copper(II) ions in such a way that there is a plane of symmetry passing through both Ge atoms and the unique Cu atom, resulting in…

Hepatic Sinusoidal Dilatation: A Review of Causes With Imaging-Pathologic Correlation.

2016

Hepatic sinusoids are vascular conduits connecting the portal triad with the central vein. Multiple conditions can lead to sinusoidal dilatation and congestion with resultant stasis of blood within the lumen. The altered hemodynamics associated with hepatic sinusoidal dilatation generally result in heterogeneous enhancement of the hepatic parenchyma on contrast-enhanced computed tomography and magnetic resonance imaging, a pattern often described as “mosaic” enhancement. In this article, we review the causes of hepatic sinusoidal dilatation and the imaging manifestations on contrast-enhanced computed tomography and magnetic resonance.

Iepazīšanās portāla lietošanas motīvi un personības tumšā triāde

2020

Pētījuma mērķis bija noskaidrot kāda sakarība pastāv starp iepazīšanās portālu lietošanas motīviem un tumšās triādes personības iezīmēm. Pētījumā piedalījās 686 Latvijas iepazīšanās portāla Otrapuse.lv lietotāji, 420 sievietes un 266 vīrieši. Pētījumā tika uzmantotas divas aptaujas: Īsā tumšās triādes skala (Short Dark Triad Scale, Jones & Paulhus, 2014). Latvijā metodi adaptējusi Laima Baldiņa (Baldiņa, 2017); Iepazīšanās portāla Otrapuse.lv lietošanas motīvi aptauja ( Tinder Motives Scale (TMS), Timmermans & De Caluwé, 2017). Aptauja tika adaptēta maģistra darba ietvaros. Pētījumā izvirzītie jautājumi: 1. Kāda sakarība pastāv starp iepazīšanās portāla lietošanas motīviem un tumšās triādes…

The Psychopathy Checklist and non-violent offender groups

1992

Cleckley’s concept of psychopathy includes characteristics such as superficial charm, unreliability, and affective poverty. In this study, the Psychopathy Checklist (PCL) and personality questionnaires (MMPI, CPI, EPQ, and SSS) were used to assess 92 non-violent male offenders. The variable-based approach was applied in order to study the structure of the PCL and the relationships between the PCL, the PCL factors and the personality questionnaire scores. The results indicated that the personality scale scores failed to correlate positively with the PCL score, with the exception of the MMPI hypomania score. Two PCL factors emerged: factor 1 related to the core personality characteristics of …

Distant Homology Modeling of LCAT and Its Validation through In Silico Targeting and In Vitro and In Vivo Assays

2013

LCAT (lecithin:cholesterol acyltransferase) catalyzes the transacylation of a fatty acid of lecithin to cholesterol, generating a cholesteryl ester and lysolecithin. The knowledge of LCAT atomic structure and the identification of the amino acids relevant in controlling its structure and function are expected to be very helpful to understand the enzyme catalytic mechanism, as involved in HDL cholesterol metabolism. However - after an early report in the late '90 s - no recent advance has been made about LCAT three-dimensional structure. In this paper, we propose an LCAT atomistic model, built following the most up-to-date molecular modeling approaches, and exploiting newly solved crystallog…