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711.
Itoh Takeshi; Aiba Hiroji; Baba Tomoya; Hayashi Kouji; Inada Toshifumi; Isono Katumi; Kasai Hiroaki; Kimura Shigenobu; Kitakawa Madoka; Kitagawa Masanari; Makino Kozo; Miki Takeyoshi; Mizobuchi Kiyoshi; Mori Hirotada; Mori Tomoko; Motomura Kouji; Nakade Shinsuke; Nakamura Yoshikazu; Nashimoto Hiroko; Nishio Yoshitaka; Oshima Taku; Saito Noriko; Sampei Gen-ichi; Seki Yasushi; Sivasundaram Suharnan; Tagami Hideaki; Takeda Jun-ichi; Takemoto Keiko; Wada Chieko; Yamamoto Yoshihiro; Horiuchi Takashi 《DNA research》1996,3(6):379-392
The 465,813 base pair sequence corresponding to the 40.150.0min region on the genetic map of Escherichia coli K-12 (W3110)was determined. Analysis of the sequence revealed that thisregion contained at least 466 potential open reading frames,of which 187 (40%) were previously reported, 105 (23%) werehomologous to other known genes, 103 (22%) were identical orsimilar to hypothetical genes registered in databases, and theremaining 71 (15%) did not show a significant similarity toany other gene. At the 45.246.0 min region, we founda very large cluster of about 30 genes, whose functions areinvolved in the biosynthesis of polysaccharides as the componentsof outer membranes. In addition, we identified anew asn-tRNAgene, designated asnW, between the asnT and asnU genes and anew lysogenic phage attachment site as the cis-element. 相似文献
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Takahiro Yamashiro Tomoya Yasujima Hamid M. Said Hiroaki Yuasa 《The Journal of biological chemistry》2020,295(50):16998
SLC19A2 and SLC19A3, also known as thiamine transporters (THTR) 1 and 2, respectively, transport the positively charged thiamine (vitamin B1) into cells to enable its efficient utilization. SLC19A2 and SLC19A3 are also known to transport structurally unrelated cationic drugs, such as metformin, but whether this charge selectivity extends to other molecules, such as pyridoxine (vitamin B6), is unknown. We tested this possibility using Madin-Darby canine kidney II (MDCKII) cells and human embryonic kidney 293 (HEK293) cells for transfection experiments, and also using Caco-2 cells as human intestinal epithelial model cells. The stable expression of SLC19A2 and SLC19A3 in MDCKII cells (as well as their transient expression in HEK293 cells) led to a significant induction in pyridoxine uptake at pH 5.5 compared with control cells. The induced uptake was pH-dependent, favoring acidic conditions over neutral to basic conditions, and protonophore-sensitive. It was saturable as a function of pyridoxine concentration, with an apparent Km of 37.8 and 18.5 μm, for SLC19A2 and SLC19A3, respectively, and inhibited by the pyridoxine analogs pyridoxal and pyridoxamine as well as thiamine. We also found that silencing the endogenous SLC19A3, but not SLC19A2, of Caco-2 cells with gene-specific siRNAs lead to a significant reduction in carrier-mediated pyridoxine uptake. These results show that SLC19A2 and SLC19A3 are capable of recognizing/transporting pyridoxine, favoring acidic conditions for operation, and suggest a possible role for these transporters in pyridoxine transport mainly in tissues with an acidic environment like the small intestine, which has an acidic surface microclimate. 相似文献
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Efficient syntheses are described of the branched d-mannopentaosides methyl 2,6-di-O-(2-O-α-d-mannopyranosyl-α-d-mannopyranosyl)α-d-mannopyranoside and methyl 2,4-di-O-(2-O-α-d-mannopyranosyl-α-d-mannopyranosyl)-α-d-mannopyranoside, starting from the glycosyl acceptors methyl 3,4-di-O-benzyl-α-d-mannopyranoside and methyl 3,6-di-O-benzyl-α-d-mannopyranoside, and employing the protected d-mannotriosides methyl 3,4-di-O-benzyl-2,6-di-O-(3,4,6-tri-O-benzyl-α-d-mannopyranosyl)-α-d-mannopyranoside, and methyl 3,6-di-O-benzyl-2,4-di-O-(3,4,6-tri-O-benzyl-α-d-mannopyranosyl)-α-d-mannopyranoside as key intermediates. 相似文献
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