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991.
SH3‐like motif‐containing C‐terminal domain of staphylococcal teichoic acid transporter suggests possible function
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Tzu‐Ping Ko Shih‐Ting Tseng Shu‐Jung Lai Sheng‐Chia Chen Hong‐Hsiang Guan Chia Shin Yang Chun Jung Chen Yeh Chen 《Proteins》2016,84(9):1328-1332
The negatively charged bacterial polysaccharides—wall teichoic acids (WTAs) are synthesized intracellularly and exported by a two‐component transporter, TagGH, comprising a transmembrane subunit TagG and an ATPase subunit TagH. We determined the crystal structure of the C‐terminal domain of TagH (TagH‐C) to investigate its function. The structure shows an N‐terminal SH3‐like subdomain wrapped by a C‐terminal subdomain with an anti‐parallel β‐sheet and an outer shell of α‐helices. A stretch of positively charged surface across the subdomain interface is flanked by two negatively charged regions, suggesting a potential binding site for negatively charged polymers, such as WTAs or acidic peptide chains. Proteins 2016; 84:1328–1332. © 2016 Wiley Periodicals, Inc. 相似文献
992.
Wang Wen-Tung Lee Phil Dong Yafeng Yeh Hung-Wen Kim Jieun Weiner Carl P. Brooks William M. Choi In-Young 《Neurochemical research》2016,41(7):1831-1843
Neurochemical Research - The guinea pig is a frequently used animal model for human pregnancy complications, such as oxygen deprivation or hypoxia, which result in altered brain development. To... 相似文献
993.
Sweet potato NAC transcription factor,IbNAC1, upregulates sporamin gene expression by binding the SWRE motif against mechanical wounding and herbivore attack
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995.
We are exploring the active site and the mechanism of the pyridoxal phosphate dependent reactions of the bacterial tryptophan synthase alpha 2 beta 2 complex by use of substrate analogues and of reaction intermediate analogues. Fluorine-19 nuclear magnetic resonance studies and absorption spectroscopy are used to study the binding and reactions of the D and L isomers of 5-fluorotryptophan, of tryptophan, and of (3S)- and (3R)-2,3-dihydro-5-fluorotryptophan. Tryptophan synthase specifically and tightly binds the 3S diastereoisomer of both 2,3-dihydro-5-fluoro-D-tryptophan and 2,3-dihydro-5-fluoro-L-tryptophan, whereas it binds 5-fluoro-D-tryptophan more tightly than 5-fluoro-L-tryptophan. Unexpectedly, we find that the D and L isomers of 5-fluorotryptophan, of tryptophan, and of (3S)-2,3-dihydro-5-fluorotryptophan are slowly interconverted by isomerization reactions. Since these isomerization reactions are 10(3)-10(5) times slower than the beta-replacement and beta-elimination reactions catalyzed by tryptophan synthase, they have no biochemical significance in vivo. However, the occurrence of these slow reactions does throw some light on the nature of the active site of tryptophan synthase and its requirements for substrate binding. Our results raise the interesting question of whether tryptophan synthase itself serves a catalytic role in these slow reactions or whether the enzyme simply binds the substrate and pyridoxal phosphate stereospecifically and thus promotes the intrinsic catalytic activity of pyridoxal phosphate. 相似文献
996.
我们应用破伤风类毒素体外免疫的人扁桃体细胞和人-鼠异源骨髓瘤RF 系细胞进行融合,从中筛选到一株杂交瘤细胞89112—50,并通过克隆化筛选获得了两个亚克隆,其分泌的抗体是抗原特异的,和三种抗原(OVA、TC-S、FYG)都不交叉,分泌抗体的功能也比较稳定,在培养瓶内连续扩增传代13次后,仍维持相当高的抗体分泌能力,在常规传代培养过程中所收集的培养物上清液中抗体的含量平均为69.6μg/ml。 相似文献
997.
本文报道了用含v-fos基因的pFBJ-2质粒转染NIH 3 T 3细胞,获得了转化细胞株。对细胞株的研究结果表明:(1)Southern杂交检测到细胞基因组中有v-fos基因的整合;(2)点杂交测得有v-fos mRNA的表达;(3)出现一系列转化表型,包括细胞形态的改变,异常的增长速率,在软琼脂上的贴壁不依赖性生长,对低血清浓度培养液的适应性以及细胞膜表而超微结构的变化等,提示v-fos基因能使NIH 3 T 3细胞发生转化,并在体外转化过程中起决定性作用。 相似文献
998.
The biosynthesis and intracellular transport of glycoproteins in duodenal absorptive cells of intact rats at 6 and 24 days and hypophysectomized rats at 24 days of age were studied after 20 min intralumenal pulse-labeling of d-[3H]galactose, l-[3H]fucose, or d-[3H]mannose. Autoradiographic studies showed that the incorporation of sugars increased significantly in intact rats between 6 and 24 days. When rats were hypophysectomized at 6 days of age, the intestinal epithelium at 24 days incorporated d-[3H]galactose at a level significantly lower than that of intact rats at 24 days. Hypophysectomy also interfered with the developmental increase in d-[3H]mannose, but not in l-[3H]fucose, incorporation. Biochemical study indicated that the radioactivity in the lipid-free acid-precipitable glycoproteins in the intestine of 24-day-old intact rats at 20 min after d-[3H]galactose injection was 129% and 97% higher than that in 6-day-old rats and in 24-day-old hypophysectomized rats, respectively. The patterns of intracellular transport of newly synthesized galactosylated or fucosylated glycoproteins in all animal groups were similar; the labeled glycoproteins were initially present in the Golgi and were transported through the smooth endoplasmic reticulum to either the lateral membrane or the brush-border membrane within 60 min after the injection of labeled sugars. The proportion of labeled glycoproteins that migrated to the brush-border membrane, however, increased about twofold in the intact rats between 6 and 24 days of age at 60–240 min after d-[3H]galactose injection. Hypophysectomy interfered with developmental increase in the transport of glycoproteins from the apical cytoplasm to the brush-border membrane. It was concluded that the incorporation of monosaccharide precursors into glycoproteins and the porportion of newly synthesized galactosylated or fucosylated glycoproteins transported to the brush-border membrane increase during postnatal development. The developmental changes are regulated, at least partially, by the pituitary gland. 相似文献
999.
Conformation of the antifreeze glycoprotein of polar fish 总被引:5,自引:0,他引:5
C A Bush S Ralapati G M Matson R B Yamasaki D T Osuga Y Yeh R E Feeney 《Archives of biochemistry and biophysics》1984,232(2):624-631
High-field proton and 13C NMR spectroscopy has been used to test and refine the recent proposal, based on vacuum uv circular dichroism results, of a threefold left-handed helical conformation for antifreeze glycoprotein (AFGP). Partial assignment of the protons of the glycotripeptide repeating unit has been made by comparison with spectra of model compounds, by selective decoupling, and by measurements of nuclear Overhauser effect (nOe). At 40 degrees C, AFGP fraction 8 (Mr 2600) shows 2-Hz linewidths which broaden at lower temperature. Neither 1H nor 13C chemical shifts depend strongly on temperature, suggesting no abrupt conformational transition. The nOe between alanine alpha and beta protons vary with temperature and with field strength, from small positive enhancements at 50 degrees C and 80 MHz to large negative effects at 3 degrees C and 300 MHz, indicating a substantial change of rotational correlation time with temperature. The higher-molecular-weight fraction 1-4 shows negative nOe at all temperatures. The CD spectra of fraction 1-4 show bands characteristic of the polyproline II structure at both 3 and 50 degrees C, while those bands in fraction 8 are weaker at 50 than 3 degrees C. The 1H nOe, the 13C T1, and CD data are interpreted as indicating that AFGP fraction 8 is an extended "rod-like" conformation at low temperature which becomes a flexible coil at high temperature, while fraction 1-4 is a flexible rod with sufficient segmental mobility to eliminate any long-range order. 相似文献
1000.