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.
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