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Alexander N. Glazer Yvonne M. Gindt Crystal F. Chan Kenneth Sauer 《Photosynthesis research》1994,40(2):167-173
Efficient production of ATP and NADPH by the light reactions of oxygen-evolving photosynthesis demands continuous adjustment of transfer of absorbed light energy from antenna complexes to Photosystem I (PS I) and II (PS II) reaction center complexes in response to changes in light quality. Treatment of intact cyanobacterial cells with N-ethylmaleimide appears to disrupt energy transfer from phycobilisomes to Photosystem I (PS I). Energy transfer from phycobilisomes to Photosystem II (PS II) is unperturbed. Spectroscopic analysis indicates that the individual complexes (phycobilisomes, PS II, PS I) remain functionally intact under these conditions. The results are consistent with the presence of connections between phycobiliproteins and both PS II and PS I, but they do not support the existence of direct contacts between the two photosystems.Abbreviations Chl chlorophyll - EPR electron paramagnetic resonance - NEM N-ethylmaleimide - PBS phycobilisome - PS photosystem 相似文献
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Sokolova O Cecala C Gopal A Cortazar F McDowell-Buchanan C Sancar A Gindt YM Schelvis JP 《Biochemistry》2007,46(12):3673-3681
Photolyases and cryptochromes are flavoproteins that belong to the class of blue-light photoreceptors. They usually bind two chromophores: flavin adenine dinucleotide (FAD), which forms the active site, and a light-harvesting pigment, which is a 5,10-methenyltetrahydrofolate polyglutamate (MTHF) in most cases. In Escherichia coli photolyase (EcPhr), the MTHF cofactor is present in substoichiometric amounts after purification, while in Vibrio cholerae cryptochrome-1 (VcCry1) the MTHF cofactor is bound more strongly and is present at stoichiometric levels after purification. In this paper, we have used resonance Raman spectroscopy to monitor the effect of loss of MTHF on the protein-FAD interactions in EcPhr and to probe the protein-MTHF interactions in both EcPhr and VcCry1. We find that removal of MTHF does not perturb protein-FAD interactions, suggesting that it may not affect the physicochemical properties of FAD in EcPhr. Our data demonstrate that the pteridine ring of MTHF in EcPhr has different interactions with the protein matrix than that of MTHF in VcCry1. Comparison to solution resonance Raman spectra of MTHF suggests that the carbonyl of its pteridine ring in EcPhr experiences stronger hydrogen bonding and a more polar environment than in VcCry1, but that hydrogen bonding to the pteridine ring amine hydrogens is stronger in VcCry-1. These differences in hydrogen bonding may account for the higher binding affinity of MTHF in VcCry1 compared to EcPhr. 相似文献
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Sohrab?P?Shah David?YM?He Jessica?N?Sawkins Jeffrey?C?Druce Gerald?Quon Drew?Lett Grace?XY?Zheng Tao?Xu BF?Francis?OuelletteEmail author 《BMC bioinformatics》2004,5(1):40
Background
We present Pegasys – a flexible, modular and customizable software system that facilitates the execution and data integration from heterogeneous biological sequence analysis tools. 相似文献5.
Thomas Haubenthal Philipp Hansen Ina Krämer Mélanie Gindt Alexandra Jünger-Leif Olaf Utermöhlen Albert Haas 《Molecular microbiology》2023,119(3):285-301
Gram-positive Rhodococcus equi (Prescotella equi) is a lung pathogen of foals and immunocompromised humans. Intra-macrophage multiplication requires production of the bacterial Virulence-associated protein A (VapA) which is released into the phagosome lumen. VapA pH-neutralizes intracellular compartments allowing R. equi to multiply in an atypical macrophage phagolysosome. Here, we show that VapA does not support intra-macrophage growth of several other bacterial species demonstrating that only few bacteria have the specific preadaptations needed to profit from VapA. We show that the closest relative of R. equi, environmental Rhodococcus defluvii (Prescotella defluvii), does not multiply in macrophages at 37°C even when VapA is present because of its thermosensitivity but it does so once the infection temperature is lowered providing rare experimental evidence for ‘thermal restriction’. Using growth experiments with isolated macrophage lysosomes and modified infection schemes we provide evidence that R. equi resists the attack by phagolysosome contents at low pH for several hours. During this time, R. equi produces and secretes VapA which enables it to grow at the expense of lysosome constituents. We present arguments that, under natural infection conditions, R. equi is VapA-less during the initial encounter with the host. This has important implications for vaccine development. 相似文献
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Hernández Pérez A E Cerna Chávez JC Delgado Ortiz M Beltrán Beache LM Tapia Vargas YM Ochoa Fuentes 《Phyton》2019,88(1):11-13
Mexico is the main producer, consumer and exporterof avocado in the world, being Michoacan the main producer statecontributing more than 80% of the national production. Thereare phytopathogens that decimate the production causing thedeath of the tree. Root samples were collected in avocado treesthat showed the characteristic symptomatology of the diseaseknown as avocado sadness, the sampling was carried out in fourof the main avocado producing towns, in the state of Michoacan,Mexico. The isolation consisted in sowing root tissue in Petridishes with V8®-PARPH culture medium, subsequently they wereidentified morphologically and for species level it was determinedby molecular biology, with the PCR-ITS technique. Pathogenicitytests were performed in triplicate with avocado seedlings with morethan six leaves. After 24 hours, the inoculated plants expresseddecay in the apical part, after 120 hours the leaves showed yellowingand after 15 days there was a generalized wilt on the stem andleaves, re-isolating the phytopathogen Phytopythium vexans.This study confirms the first report of the oomycete P. vexansaffecting avocado trees in the most important producing region ofthe Mexican Republic. 相似文献
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