• Title, Summary, Keyword: Synechocystis PCC 6803

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Protein Cyclization Enhanced Thermostability and Exopeptidase-Resistance of Green Fluorescent Protein

  • Zhao, Zhonglin;Ma, Xin;Li, Liang;Zhang, Wei;Ping, Shuzhen;Xu, Ming-Qun;Lin, Min
    • Journal of Microbiology and Biotechnology
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    • v.20 no.3
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    • pp.460-466
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    • 2010
  • A mutant of green fluorescent protein ($GFPmut3^*$) from the jellyfish Aequorea victoria was cyclized in vitro and in vivo by the use of a naturally split intein from the dnaE gene of Synechocystis species PCC6803 (Ssp). Cyclization of $GFPmut3^*$ was confirmed by amino acid sequencing and resulted in an increased electrophoretic mobility compared with the linear $GFPmut3^*$. The circular $GFPmut3^*$ was $5^{\circ}C$ more thermostable than the linear form and significantly more resistant to proteolysis of exopeptidase. The circular $GFPmut3^*$ also displayed increased relative fluorescence intensity. In addition, chemical stability of $GFPmut3^*$ against GdnHCl revealed more stability of the circular form compared with the linear form.

Structural Determination of Fatty Acyl Groups of Phospholipids by Fast Atom Bombardment Tandem Mass Spectrometry of Sodium Adduct Molecular Ions

  • 김영환;유종신;김명수
    • Bulletin of the Korean Chemical Society
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    • v.18 no.8
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    • pp.874-880
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    • 1997
  • Various classes of phospholipids were investigated for the structural determination of fatty acyl groups by fast atom bombardment tandem mass spectrometry (FAB-MS/MS). Phospholipids were desorbed by FAB as molecules chelated with sodium ion (or ions). Collision-induced dissociation (CID) of intact sodium adduct molecular ions ([M+Na]+, [M-H+2Na]+ or [M+Na-2H]-) produced a series of homologous fragment ions via the charge-remote fragmentation along the fatty acid chains. These ions were found useful to locate the double bond positions even for the polyunsaturated fatty acid chains. The regiospecificity of the acyl chain linkages in phosphatidylcholine (PC) could also be determined based on the ratio of relative abundance of the product ions (i.e., [M+Na-85-R2COOH]+ vs [M+Na-85-R1COOH]+) in CID-MS/MS of [M+Na]+. These are generated by the loss of fatty acyl groups at sn-1 and sn-2, respectively, together with the choline group. In all the phospholipid compounds investigated, loss of the fatty acid at the sn-2 position was dominant. The present method was applied to the structural determination of molecular species of phosphatidylglycerols (PG) isolated from cyanobacterium Synechocystis sp. PCC 6803.

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Fragment Combination From DNA Sequence Data Using Fuzzy Reasoning Method (퍼지 추론기법을 이용한 DNA 염기 서열의 단편결합)

  • Kim, Kwang-Baek;Park, Hyun-Jung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.12
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    • pp.2329-2334
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    • 2006
  • In this paper, we proposed a method complementing failure of combining DNA fragments, defect of conventional contig assembly programs. In the proposed method, very long DNA sequence data are made into a prototype of fragment of about 700 bases that can be analyzed by automatic sequence analyzer at one time, and then matching ratio is calculated by comparing a standard prototype with 3 fragmented clones of about 700 bases generated by the PCR method. In this process, the time for calculation of matching ratio is reduced by Compute Agreement algorithm. Two candidates of combined fragments of every prototype are extracted by the degree of overlapping of calculated fragment pairs, and then degree of combination is decided using a fuzzy reasoning method that utilizes the matching ratios of each extracted fragment, and A, C, G, T membership degrees of each DNA sequence, and previous frequencies of each A, C, G, T. In this paper. DNA sequence combination is completed by the iteration of the process to combine decided optimal test fragments until no fragment remains. For the experiments, fragments or about 700 bases were generated from each sequence of 10,000 bases and 100,000 bases extracted from 'PCC6803', complete protein genome. From the experiments by applying random notations on these fragments, we could see that the proposed method was faster than FAP program, and combination failure, defect of conventional contig assembly programs, did not occur.

Cyanobacterial Hybrid Kinase Sll0043 Regulates Phototaxis by Suppressing Pilin and Twitching Motility Protein

  • Shin, Bong-Jeong;Oh, Jeehyun;Kang, Sungsoo;Chung, Young-Ho;Park, Young Mok;Kim, Young Hwan;Kim, Seungil;Bhak, Jong;Choi, Jong-Soon
    • Journal of Microbiology
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    • v.46 no.3
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    • pp.300-308
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    • 2008
  • The unicellular cyanobacterium Synechocystis sp. PCC 6803 glides toward a light source through the interplay of positive phototaxis genes and proteins. In genetic analysis, the complete disruption of the hybrid sensory kinase sll0043 produced negative phototaxis. Furthermore, Sll0043 was found to be a hub protein by in silico prediction of protein-protein interaction, in which Sll0043 was predominantly linked to seven two-component proteins with high confidence. To understand the regulation and networking of positive phototaxis proteins, the proteomic profile of the sll0043 mutant was compared to that of wild-type. In the sll0043 mutant, 18 spots corresponding to 15 unique proteins were altered by 1.3 to 59 fold; the spots were identified by 2-DE/MALDI-MS analysis. Down-regulated proteins in the sll0043 null-mutant included chaperonins, superoxide dismutase, and phycocyanin ${\beta}$-subunit. In contrast, nine proteins involved in photosynthesis, translation, regulatory function, and other functions were up-regulated. In particular, a twitching motility protein (PilT1) was induced over 2-fold in sll0043 mutant. Moreover, semi-quantitative and quantitative RT-PCR analysis revealed that pilin (pilA1), pili motor (pilT1), and pili switch gene (pilT2) were significantly increased in sll0043 mutant. These results suggest that the hybrid kinase Sll0043 regulates positive phototaxis by suppressing the expression of pili biosynthesis and regulatory genes and through the interplay with positive phototaxis/motility two-component proteins.