Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Singlet oxygen is reported to have the most potent damaging effect upon the photosynthetic machinery. Usually this reactive oxygen molecule acts in concert with other ROS types under stressful conditions. To understand the specific role of singlet oxygen we took advantage of the conditional flu mutant of Arabidopsis thaliana. In flu, the negative feedback loop is abolished, which blocks chlorophyll biosynthesis in the dark. Therefore high amounts of free protochlorophyllide accumulate during darkness. If flu gets subsequently illuminated, free protochlorophyllide acts as a photosensitiser leading almost exclusively to high amounts of (1)O2. Analysing the thylakoid protein pattern by using 2D PAGE and subsequent MALDI-TOF analysis, we could show, in addition to previous described effects on photosystem II, that singlet oxygen has a massive impact on the thylakoid ATP synthase, especially on its gamma subunit. Additionally, it could be shown that the activity of the ATP synthase is reduced upon singlet oxygen exposure and that the rate of non-photochemical quenching is affected in flu mutants exposed to (1)O2.
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PMID:Singlet oxygen affects the activity of the thylakoid ATP synthase and has a strong impact on its gamma subunit. 1710 25

Influenza viruses are characterized by two surface proteins - the hemagglutinin (HA) of which there are 16 varieties, and the neuraminidase (NA) of which there are 9, each subtype characterized by its antigenic properties. Although theoretically 16 x 9 combinations are possible, only a few like the H1N1, H3N2, etc are seen to occur more frequently. Numerous studies with select subtypes like H1N1, H5N1, etc., have explained this phenomena by indicating that viral viability necessitates functional balance between the NA and HA so that only some combinations are favored. However, the reasons for this balance or its characteristics and whether this is universal for influenza subtypes are not yet known. Using novel graphical techniques and hypothesizing a coupling between the HA and NA, we devised a coupling factor to estimate the interdependence, if any, between HA and NA sequences covering a global sample of 10 subtypes and 164 sequences. We found that (a) the coupling we hypothesized between HAs and NAs is characteristic of each subtype, (b) within each subtype the coupling value is significantly different for human infecting strains and those that infect avians, and (c) artificial strains made up by mixing and matching HAs and NAs from different subtypes produce coupling factors that are far from the characteristic values for the parent subtype indicating possibly non-viable viruses, a result that matches with experimental evidence of Zhang et al. [1]. We also show that some natural strains that did not fit the characteristic values for its subtype could have been possible mismatches during viral packaging. Our observations have important consequences for drug and vaccine design and for monitoring of influenza virus reassortments and possible evolution of human pandemics.
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PMID:Characteristics of influenza HA-NA interdependence determined through a graphical technique. 2579 3