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In a previous study, a mutant of tyrosyl-tRNA synthetase in which a threonine residue (Thr51) was converted to proline dramatically improved the affinity of the enzyme for its ATP substrate. How does Pro51 improve the enzyme's affinity for ATP? A priori, Pro51 might interact directly with the ATP, or it might distort the polypeptide backbone and thereby(More)
The role of complementary hydrogen bonding as a determinant of biological specificity has been examined by protein engineering of the tyrosyl-tRNA synthetase. Deletion of a side chain between enzyme and substrate to leave an unpaired, uncharged hydrogen-bond donor or acceptor weakens binding energy by only 0.5-1.5 kcal mol-1. But the presence of an unpaired(More)
CD133/prominin-1 is a pentaspan transmembrane glycoprotein overexpressed in various solid tumours including colorectal and glioblastomas. CD133 was found here to be highly expressed in >or=50% of pancreatic, gastric and intrahepatic cholangiocarcinomas. Quantitative flow cytometric analysis showed that a panel of established hepatocellular, pancreatic and(More)
The Double Star Project is a collaboration between Chinese and European space agencies, in which two Chinese magnetospheric research spacecraft, carrying Chi-nese and European instruments, have been launched into equatorial (on 29 December 2003) and polar (on 25 July 2004) orbits designed to enable complementary studies with the Cluster spacecraft. The two(More)
Inhalant abuse is a rapidly growing health problem particularly among adolescents. Yet we know little about the neural mechanisms underlying the abuse liability of inhalants, particularly when compared to other addictive drugs. Specifically, our understanding of the relationship between the regional brain phamacokinetics and features classically associated(More)
The bright night-time aurorae that are visible to the unaided eye are caused by electrons accelerated towards Earth by an upward-pointing electric field. On adjacent geomagnetic field lines the reverse process occurs: a downward-pointing electric field accelerates electrons away from Earth. Such magnetic-field-aligned electric fields in the collisionless(More)
During the first quarter of 2001 the apogees of the Cluster spacecraft quartet precessed through midday local times. This provides the first opportunity for 4 spacecraft studies of the bow shock, magnetosheath and the day-side magnetopause current layer and boundary layers. In this paper, we present observations of electrons in the energy range ∼ 10 eV–26(More)
In this study, we investigated whether treatment with L-deprenyl, a selective monoamine oxidase B (MAO B) inhibitor, also inhibits MAO A or the dopamine transporter in the human brain. Six normal volunteers (age 46+/-6 yrs) had two PET sessions, one at baseline and one following L-deprenyl (10 mg/day) for 1 week. Each session included one scan with(More)
The construction and use of a dual radiator Ring ImagingČerenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential(More)
The two PEACE (Plasma Electron And Current Experiment) sensors on board each Cluster spacecraft sample the electron velocity distribution across the full 4π solid angle and the energy range 0.7 eV to 26 keV with a time resolution of 4 s. We present high energy and angular resolution 3D observations of electrons of spacecraft origin in the various(More)