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1.
cDNA sequence and predicted primary structure of the gamma subunit from the ATP synthase from Chlamydomonas reinhardtii 总被引:3,自引:0,他引:3
The 1701-base nucleotide sequence (not including the poly(A) tail) of a cDNA for the gamma subunit of the ATP synthase from Chlamydomonas reinhardtii was determined. A start translation sequence, 23 bases in from the 5' end, initiates an 1074-base-long open reading frame. The sequence of the first 21 amino acids at the amino-terminal end of the mature gamma subunit from C. reinhardtii was determined and compared to the deduced amino acid sequence of the open reading frame. From this it was determined that the mature protein contains 323 amino acids, with the first 35 amino acids probably being part of the transit peptide. The length of the mature protein is the same as that for the mature gamma subunit from spinach, for which only a few of the amino acids of the transit peptide are known. The similarity of the two mature proteins at the nucleotide level is 56% while at the amino acid level it is 77%. In addition, the 3 cysteines, which in spinach are involved in the energy-linked catalytic functions of the ATP synthase, are conserved in the predicted amino acid sequence for the gamma subunit from C. reinhardtii. In contrast, the mature C. reinhardtii gamma subunit contains 3 additional cysteine residues not found in the spinach gamma subunit. 相似文献
2.
Background
Micro-biological research relies on the use of model organisms that act as representatives of their species or subspecies, these are frequently well-characterized laboratory strains. However, it has often become apparent that the model strain initially chosen does not represent important features of the species. For micro-organisms, the diversity of their genomes is such that even the best possible choice of initial strain for sequencing may not assure that the genome obtained adequately represents the species. To acquire information about a species' genome as efficiently as possible, we require a method to choose strains for analysis on the basis of how well they represent the species. 相似文献3.
Nucleotide-binding sites on the chloroplast coupling factor 1 (CF1) have been probed using two photoreactive ADP analogs: 2-azido-ADP (2-N3-ADP) and 2',3'-O-(4-benzoyl)benzoyl-ADP (Bz-ADP). Photolabeling of the isolated CF1 with 2-N3-ADP results in incorporation of the analog exclusively into the beta-subunit of the enzyme. The location of the nucleotide-binding site(s) within the beta-subunit of the CF1 was investigated using peptide mapping. Within the discrimination limits of this technique, it is concluded that the azido- and benzoyl-modified analogs both bind to the same conformation of the nucleotide-binding site(s) of soluble CF1. Bz-ADP, however, labels the binding site(s) on membrane-bound CF1 in a slightly different manner. 相似文献
4.
Inhibition of coupling factor activity of chloroplast membranes by diazonium compounds 总被引:2,自引:0,他引:2
R T Giaquinta B R Selman C L Bering R A Dilley 《The Journal of biological chemistry》1974,249(9):2873-2878
5.
ATP is required for the binding of precursor proteins to chloroplasts 总被引:30,自引:0,他引:30
L J Olsen S M Theg B R Selman K Keegstra 《The Journal of biological chemistry》1989,264(12):6724-6729
One of the first steps in the transport of nuclear-encoded, cytoplasmically synthesized precursor proteins into chloroplasts is a specific binding interaction between precursor proteins and the surface of the organelle. Although protein translocation into chloroplasts requires ATP hydrolysis, binding is generally thought to be energy independent. A more detailed investigation of precursor binding to the surface of chloroplasts showed that ATP was required for efficient binding. Protein translocation is known to require relatively high levels (1 mM or more) of ATP. As little as 50-100 microM ATP caused significant stimulation of precursor binding over controls with no ATP. Several different precursors were tested and all showed increased binding upon addition of low levels of ATP. Nonhydrolyzable analogs of ATP did not substitute for ATP, indicating that ATP hydrolysis was required for binding. A protonmotive force was not involved in the energy requirement for binding. Other (hydrolyzable) nucleotides could substitute for ATP but were less effective at stimulating binding. Binding was stimulated by ATP generated inside chloroplasts even when an ATP trap was present to destroy external ATP. We conclude that internal ATP is required for stimulation of precursor binding to chloroplasts. 相似文献
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7.
Different values have resulted in conflicts between anglers and conservation lobbies in the management of trout in South Africa. Key to the conflict is the demarcation of boundaries to areas in which brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss currently occur, or are likely to establish following stocking for angling. To provide a longer-term perspective on these areas, we developed models to link salmonid biological thermal thresholds to elevation. These, when applied spatially using a digital elevation model with a probability of occurrence model, provided the basis for estimating potentially available thermal habitat for these two cold water species. Here, we acknowledge that other variables (stocking history; river connectivity) also play a role in understanding trout distributions. Using a simple scenario of an increase in mean daily water temperatures of 2 °C, we demonstrated that both brown and rainbow trout are likely to exhibit considerable range reductions in the future. Because it is possible that these range restrictions will result in an increasing desire to introduce trout into areas above their current distribution limits for the maintenance of angling opportunities, conservation managers should prioritise these areas, with management interventions seeking to understand what will help to limit introductions. 相似文献
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9.
ALICE NICOLLE PER HALLGREN JESSICA
Von EINEM EMMA SOFIA KRITZBERG WILHELM GRANÉLI ANDERS PERSSON CHRISTER BRÖNMARK LARS‐ANDERS HANSSON 《Freshwater Biology》2012,57(4):684-695
1. Aquatic ecosystems in Northern Europe are expected to face increases in temperature and water colour (TB) in future. While effects of these factors have been studied separately, it is unknown whether and how a combination of them might affect phenological events and trophic interactions. 2. In a mesocosm study, we combined both factors to create conditions expected to arise during the coming century. We focused on quantifying effects on timing and magnitude of plankton spring phenological events and identifying possible mismatches between resources (phytoplankton) and consumers (zooplankton). 3. We found that the increases in TB had important effects on timing and abundance of different plankton groups. While increased temperature led to an earlier peak in phytoplankton and zooplankton and a change in the relative timing of different zooplankton groups, increased water colour reduced chlorophyll‐a concentrations. 4. Increased TB together benefitted cladocerans and calanoid copepods and led to stronger top‐down control of algae by zooplankton. There was no sign of a mismatch between primary producers and grazers as reported from other studies. 5. Our results point towards an earlier onset of plankton spring growth in shallow lakes in future with a stronger top‐down control of phytoplankton by zooplankton grazers. 相似文献
10.