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Ajitha Thanabalasuriar Athanasia Koutsouris rew Weflen Mark Mimee Gail Hecht Samantha Gruenheid 《Cellular microbiology》2010,12(1):31-41
Enteropathogenic Escherichia coli (EPEC) is a diarrhoeal pathogen that adheres to epithelial cells of the small intestine and uses a type III secretion system to inject effector proteins into host cells. EPEC infection leads to disruption of host intestinal tight junctions that are important for maintaining intestinal barrier function. This disruption is dependent on the bacterial type III secretion system, as well as the translocated effectors EspF and Map. Here we show that a third type III translocated bacterial effector protein, NleA, is also involved in tight junction disruption during EPEC infection. Using the drug Brefeldin A, we demonstrate that the effect of NleA on tight junction integrity is related to its inhibition of host cell protein trafficking through COPII-dependent pathways. These results suggest that NleA's striking effect on virulence is mediated, at least in part, via its role in disruption of intestinal barrier function. 相似文献
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Jimmy Heimdal Kasper P. Jensen Ajitha Devarajan Ulf Ryde 《Journal of biological inorganic chemistry》2007,12(1):49-61
We have studied the effect of axial ligation of chlorophyll and bacteriochlorophyll using density functional calculations.
Eleven different axial ligands have been considered, including models of histidine, aspartate/glutamate, asparagine/glutamine,
serine, tyrosine, methionine, water, the protein backbone, and phosphate. The native chlorophylls, as well as their cation
and anion radical states and models of the reaction centres P680 and P700, have been studied and we have compared the geometries,
binding energies, reduction potentials, and absorption spectra. Our results clearly show that the chlorophylls strongly prefer
to be five-coordinate, in accordance with available crystal structures. The axial ligands decrease the reduction potentials,
so they cannot explain the high potential of P680. They also redshift the Q band, but not enough to explain the occurrence
of red chlorophylls. However, there is some relation between the axial ligands and their location in the various photosynthetic
proteins. In particular, the intrinsic reduction potential of the second molecule in the electron transfer path is always
lower than that of the third one, a feature that may prevent back-transfer of the electron. 相似文献
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