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Molecular Analysis of Plant DNA Genomes: Conserved and Diverged DNA Sequences
Published in S. K. Dutta, DNA Systematics, 2019
Since homologies were detected in amino acid sequences of the plastocyanins of phylogenetically distant species,61 the genes of this protein, as well as those of other copper-containing “blue” proteins, may be suitable for the study of the distant evolutionary relationships of plant taxa.
Ascorbic Acid
Published in Ruth G. Alscher, John L. Hess, Antioxidants in Higher Plants, 2017
Ascorbate will also influence the reactivity of the molecular complex to which it is bound because the highly active hydroxy group of the C2 is not directly affected by the monovalent intermolecular bond at carbon atom 3.101 Ascorbate binds to the thylakoid membranes in a ratio of 0.5 ± 0.1 mg ascorbate mg-1 chlorophyll.102 The binding of ascorbate to stroma-exposed components of the electron transport chain will have some significance for their function. Transfer of electrons from ascorbate to several components of the electron transport chain, e.g., plastoquinone, plastocyanin, cytochrome b559, and cytochrome f (Figure 10) has been demonstrated. Although such transport of electrons is not sufficiently rapid to compete with the light-driven transport of electrons from PS II, it might affect the poising of the redox state of the electron carriers.
Cytochrome c Oxidase
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
Steffens and Buse59 found that the part of the polypeptide sequence which is not buried in the membrane shows considerable homology to well-known copper proteins of the azurin,102 plastocyanin,103 and stellacyanin104 family.105 This homology includes the residues which in the X-ray structures of azurin106 and plastocyanin107 have been shown to bind the copper (Table 4).
Discovery of CRR1-targeted copper deficiency response in Chlamydomonas reinhardtii exposed to silver nanoparticles
Published in Nanotoxicology, 2019
Songshan Wang, Jitao Lv, Shuzhen Zhang
The up-regulation of copper homeostasis genes in E. coli exposed to AgNPs has been reported in a previous study (McQuillan and Shaw 2014), and this was attributed to the parallels in chemistry between silver and copper. Based on observations in the present study, this phenomenon can be reasonably explained as the result of a copper deficiency response. Similarly, earlier research on human cells exposed to AgNPs found that the cellular energy supply was switched from oxidative phosphorylation-based aerobic metabolism to anaerobic glycolysis (Chen et al. 2014). It is very likely that functional copper deficiency is the root cause of this phenomenon due to the critical role of cytochrome oxidase (copper containing protein) in the aerobic respiratory electron-transport chain for generating ATP. Furthermore, copper deficiency responses have been connected to the adaptation to anaerobic conditions (Hemschemeier et al. 2013), membrane structure maintenance (Yang et al. 2015), and reallocation of copper from plastocyanin to cytochrome oxidase in copper-depleted environments in algae (Kropat et al. 2015). Therefore, the finding of a functional copper deficiency response in the present study provides a new insight into our understanding of the AgNP–biological interactions in algae and possibly other organisms.