Trypanosoma brucei protein arginine methyltransferase 7 (TbPRMT7) exclusively generates monomethylarginine (MMA), which directs biological consequences distinct from that of symmetric dimethylarginine (SDMA) and asymm...
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Trypanosoma brucei protein arginine methyltransferase 7 (TbPRMT7) exclusively generates monomethylarginine (MMA), which directs biological consequences distinct from that of symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). However, determinants controlling the strict monomethylation activity are unknown. We present the crystal structure of the TbPRMT7 active core in complex with S-adenosyl-L-homocysteine (AdoHcy) and a histone H4 peptide substrate. In the active site, residues E172, E181, and Q329 hydrogen bond the guanidino group of the target arginine and align the terminal guanidino nitrogen in a position suitable for nucleophilic attack on the methyl group of S-adenosyl-L-methionine (AdoMet). Structural comparisons and isothermal titration calorimetry data suggest that the TbPRMT7 active site is narrower than those of protein arginine dimethyltransferases, making it unsuitable to bind MMA in a manner that would support a second turnover, thus abolishing the production of SDMA and ADMA. Our results present the structural interpretations for the monomethylation activity of TbPRMT7.
Electronic image stabilization (EIS) technology is an important research area of video processing and computer vision. This paper presented a set of fast and parallel EIS algorithms. Firstly, this paper proposed a fas...
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Electronic image stabilization (EIS) technology is an important research area of video processing and computer vision. This paper presented a set of fast and parallel EIS algorithms. Firstly, this paper proposed a fast local motion vector (LMV) estimation algorithm based on the FAST feature to solve the problem that the traditional algorithm is too complex. Secondly, a parallel global motion vector (GMV) algorithm based on image division is designed, which computes every LMV simultaneously, and then estimates the GMV by all LMVs. Finally, based on the proposed algorithm, an EIS systems based on BF609 dual-core DSP processor is designed and implemented. Experiment results show that the algorithm and system presented in this thesis can effectively stabilize jittery video and achieve high real-time performance. When dealing with PAL standard video, the total time cost is less than 40ms.
[Objective] Temperature of a subject's external body parts is an interference condition in pulse wave of local blood volume measurement. It is necessary to rule it out. By changing the influence factors, an experi...
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[Objective] Temperature of a subject's external body parts is an interference condition in pulse wave of local blood volume measurement. It is necessary to rule it out. By changing the influence factors, an experiment to research the effect of temperature of subjected part in pulse wave of local blood volume measurement was carried out. [Methods] When the 32 experimenters' left middle finger temperature fall below to 20°C, pulse wave of local blood volume would be recorded detected in real-time until the temperature returned to the measured values before the experiment [Results] While the temperature of subjected part ranged from 26°C to 31°C, the parameters of K', K1', K2' and the amplitude of pulse wave remain basically unchanged. [Conclusion] As a result of the research data, it is stipulated that the pulse wave of local blood volume can be measured only if the finger temperature is in the range of 26-31°C.
We recently reported that zacopride is a selective inward rectifier potassium current (IK1 ) channel agonist, suppressing ventricular arrhythmias without affecting atrial arrhythmias. The present study aimed to invest...
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We recently reported that zacopride is a selective inward rectifier potassium current (IK1 ) channel agonist, suppressing ventricular arrhythmias without affecting atrial arrhythmias. The present study aimed to investigate the unique pharmacological properties of zacopride. The whole-cell patch-clamp technique was used to study IK1 currents in rat atrial myocytes and Kir2.x currents in human embryonic kidney (HEK)-293 cells transfected with inward rectifier potassium channel (Kir)2.1, Kir2.2, Kir2.3, or mutated Kir2.1 (at phosphorylation site S425L). Western immunoblots were performed to estimate the relative protein expression levels of Kir2.x in rat atria and ventricles. Results showed that zacopride did not affect the IK1 and transmembrane potential of atrial myocytes. In HEK293 cells, zacopride increased Kir2.1 homomeric channels by 40.7%±9.7% at 50 mV, but did not affect Kir2.2 and Kir2.3 homomeric channels, and Kir2.1-Kir2.2, Kir2.1-Kir2.3 and Kir2.2-Kir2.3 heteromeric channels. Western immunoblots showed that similar levels of Kir2.3 protein were expressed in rat atria and ventricles, but atrial Kir2.1 protein level was only 25% of that measured in the ventricle. In addition, 5-hydroxytryptamine (5-HT) 3 receptor was undetectable, whereas 5-HT 4 receptor was weakly expressed in HEK293 cells. The Kir2.1-activating effect of zacopride in these cells was abolished by inhibition of protein kinase A (PKA), but not PKC or PKG. Furthermore, zacopride did not activate the mutant Kir2.1 channel in HEK293 cells but selectively activated the Kir2.1 homomeric channel via a PKA-dependent pathway, independent to that of the 5-HT receptor.
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