排序方式: 共有282条查询结果,搜索用时 15 毫秒
1.
2.
A principal target for the environmental toxin lead (Pb) is porphobilinogen synthase (PBGS), a Zn-metalloenzyme necessary for heme biosynthesis. Measurement of blood Pb inhibited PBGS is the most sensitive indicator of subclinical Pb intoxication, but problems with the assay have diminished its use. This report identifies Pb as a slow acting inhibitor of PBGS. The activity of PBGS could change up to sixfold during an hourlong clinical assay of Pb contaminated blood, and activity is profoundly effected by the presence of serum proteins, such as albumin. When PBGS catalyzed PBG production is allowed to reach a steady state rate, kinetic data on purified PBGS support the hypothesis that Pb inhibition of PBGS results from direct substitution for Zn. 相似文献
3.
Neeru Jain Shruti Gupta Shashi B. Babbar 《Journal of plant biochemistry and biotechnology.》1997,6(2):129-131
Isubgol, the mucilaginous husk derived from the seeds of Plantago ovata, has been successfully used as a gelling agent for microbial culture media. As illustrative examples, fast growing symbiotic bacterium, Rhizobium meliloti and saprophytic fungi, Aspergillus flavus and Penicillium chrysogenum were cultured on media gelled with either Isubgol or agar. All the three microbes employed in the study exhibited normal growth when cultured on their respective media gelled with Isubgol. Rather, Isubgol gelled medium appears to promote the growth of bacterial cultures as the colonies on this medium were denser than the corresponding ones on the medium gelled with agar. Likewise, on Isubgol gelled medium, sporulation in both the fungi took place earlier than on the medium gelled with agar, thus indicating the promotive influence of the former gelling agent. 相似文献
4.
5.
Tara C. Smith Peter C. Fridy Yinyin Li Shruti Basil Sneha Arjun Ryan M. Friesen John Leszyk Brian T. Chait Michael P. Rout Elizabeth J. Luna 《Molecular biology of the cell》2013,24(23):3603-3619
Cytokinesis, the process by which cytoplasm is apportioned between dividing daughter cells, requires coordination of myosin II function, membrane trafficking, and central spindle organization. Most known regulators act during late cytokinesis; a few, including the myosin II–binding proteins anillin and supervillin, act earlier. Anillin''s role in scaffolding the membrane cortex with the central spindle is well established, but the mechanism of supervillin action is relatively uncharacterized. We show here that two regions within supervillin affect cell division: residues 831–1281, which bind central spindle proteins, and residues 1–170, which bind the myosin II heavy chain (MHC) and the long form of myosin light-chain kinase. MHC binding is required to rescue supervillin deficiency, and mutagenesis of this site creates a dominant-negative phenotype. Supervillin concentrates activated and total myosin II at the furrow, and simultaneous knockdown of supervillin and anillin additively increases cell division failure. Knockdown of either protein causes mislocalization of the other, and endogenous anillin increases upon supervillin knockdown. Proteomic identification of interaction partners recovered using a high-affinity green fluorescent protein nanobody suggests that supervillin and anillin regulate the myosin II and actin cortical cytoskeletons through separate pathways. We conclude that supervillin and anillin play complementary roles during vertebrate cytokinesis. 相似文献
6.
Timothy A. McCaffrey Constantine Tziros Jannet Lewis Richard Katz Robert Siegel William Weglicki Jay Kramer I. Tong Mak Ian Toma Liang Chen Elizabeth Benas Alexander Lowitt Shruti Rao Linda Witkin Yi Lian Yinglei Lai Zhaoqing Yang Sidney W. Fu 《International journal of biological sciences》2013,9(4):350-360
7.
Wareed Ahmed Anuradha Gopal Bhat Majety Naga Leelaram Shruti Menon Valakunja Nagaraja 《Nucleic acids research》2013,41(15):7462-7471
Bacterial DNA topoisomerase I (topoI) carries out relaxation of negatively supercoiled DNA through a series of orchestrated steps, DNA binding, cleavage, strand passage and religation. The N-terminal domain (NTD) of the type IA topoisomerases harbor DNA cleavage and religation activities, but the carboxyl terminal domain (CTD) is highly diverse. Most of these enzymes contain a varied number of Zn2+ finger motifs in the CTD. The Zn2+ finger motifs were found to be essential in Escherichia coli topoI but dispensable in the Thermotoga maritima enzyme. Although, the CTD of mycobacterial topoI lacks Zn2+ fingers, it is indispensable for the DNA relaxation activity of the enzyme. The divergent CTD harbors three stretches of basic amino acids needed for the strand passage step of the reaction as demonstrated by a new assay. We also show that the basic amino acids constitute an independent DNA-binding site apart from the NTD and assist the simultaneous binding of two molecules of DNA to the enzyme, as required during the catalytic step. Although the NTD binds to DNA in a site-specific fashion to carry out DNA cleavage and religation, the basic residues in CTD bind to non-scissile DNA in a sequence-independent manner to promote the crucial strand passage step during DNA relaxation. The loss of Zn2+ fingers from the mycobacterial topoI could be associated with Zn2+ export and homeostasis. 相似文献
8.
Mayank Singh Clayton R. Hunt Raj K. Pandita Rakesh Kumar Chin-Rang Yang Nobuo Horikoshi Robert Bachoo Sara Serag Michael D. Story Jerry W. Shay Simon N. Powell Arun Gupta Jessie Jeffery Shruti Pandita Benjamin P. C. Chen Dorothee Deckbar Markus L?brich Qin Yang Kum Kum Khanna Howard J. Worman Tej K. Pandita 《Molecular and cellular biology》2013,33(16):3390
9.
10.