Probing the Kinetic Mechanism and Coenzyme Specificity of Glutathione Reductase from the CyanobacteriumAnabaenaPCC 7120 by Redesign of the Pyridine-Nucleotide-Binding Site†

Biochemistry ◽  
1999 ◽  
Vol 38 (29) ◽  
pp. 9254-9263 ◽  
Author(s):  
U. Helena Danielson ◽  
Fanyi Jiang ◽  
Lars O. Hansson ◽  
Bengt Mannervik
Keyword(s):  
Glutathione Reductase ◽  
Binding Site ◽  
Nucleotide Binding ◽  
Kinetic Mechanism ◽  
Pyridine Nucleotide ◽  
Nucleotide Binding Site ◽  
Coenzyme Specificity

Zusammenhang zwischen Transhydrogenase- und Diaphorase-Aktivität der Ferredoxin-NADP-Reduktase und der photosynthetischen NADP-Reduktion / Relationship of Transhydrogenase and Diaphorase Activity of Ferredoxin-NADP Reductase with Photosynthetic NADP Reduction

1971 ◽  
Vol 26 (8) ◽  
pp. 807-815 ◽  
Author(s):  
Peter Böger
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Nucleotide Binding ◽  
Pyridine Nucleotide ◽  
Nucleotide Binding Site ◽  
Pyridine Nucleotides ◽  
Diaphorase Activity ◽  
Relationship Of

Photosynthetic NADP reduction, diaphorase and transhydrogenase activity of ferredoxin-NADP reductase (EC 1.6.99.4 or 1.6.1.1, from the alga Bumilleriopsis filiformis) are compared by studying the influence of pyridine nucleotides and 2'-AMP. Together with previous findings dealing with the role of ferredoxin in the two latter activities 7 the results can be compiled as follows:1. Ferredoxin-NADP reductase has two binding sites: one specific site for ferredoxin and one for pyridine nucleotides whether they are reduced or oxidized.2. There is no substantial competition between ferredoxin and pyridine nucleotides for their respective binding sites.3. Diaphorase substrates like dichlorophenolindophenol or methylviologen do not bind at the pyridine nucleotide site. It is suggested that they bind at the ferredoxin site. In vivo, therefore, the diaphorase site of the reductase is occupied by ferredoxin and represents the electron accepting part of the reductase.4. During transhydrogenase reaction ferredoxin-NADP reductase is reduced by NADPH via the pyridine nucleotide binding site; during NADP reductase reaction the enzyme is reduced by ferredoxin at the ferredoxin site. In both reactions, however, NADP (and other nucleotides) are reduced at the same pyridine nucleotide binding site. Transhydrogenase activity, therefore, appears to be an artefact reaction, which can be found when the isolated reductase is no more reduced by its natural substrate ferredoxin.

Characterization of Nucleotide Binding ­Site-Encoding Genes in Sweetpotato, Ipomoea batatas(L.) Lam., and Their Response to Biotic and Abiotic Stresses

2021 ◽  
pp. 1-15
Author(s):  
Zengzhi Si ◽  
Yake Qiao ◽  
Kai Zhang ◽  
Zhixin Ji ◽  
Jinling Han
Keyword(s):  
Binding Site ◽  
Abiotic Stresses ◽  
Ipomoea Batatas ◽  
Expression Profiles ◽  
Nucleotide Binding ◽  
Regulatory Elements ◽  
Nucleotide Binding Site ◽  
Biotic And Abiotic Stresses ◽  
Encoding Genes

Sweetpotato, <i>Ipomoea batatas</i> (L.) Lam., is an important and widely grown crop, yet its production is affected severely by biotic and abiotic stresses. The nucleotide binding site (NBS)-encoding genes have been shown to improve stress tolerance in several plant species. However, the characterization of NBS-encoding genes in sweetpotato is not well-documented to date. In this study, a comprehensive analysis of NBS-encoding genes has been conducted on this species by using bioinformatics and molecular biology methods. A total of 315 NBS-encoding genes were identified, and 260 of them contained all essential conserved domains while 55 genes were truncated. Based on domain architectures, the 260 NBS-encoding genes were grouped into 6 distinct categories. Phylogenetic analysis grouped these genes into 3 classes: TIR, CC (I), and CC (II). Chromosome location analysis revealed that the distribution of NBS-encoding genes in chromosomes was uneven, with a number ranging from 1 to 34. Multiple stress-related regulatory elements were detected in the promoters, and the NBS-encoding genes’ expression profiles under biotic and abiotic stresses were obtained. According to the bioinformatics analysis, 9 genes were selected for RT-qPCR analysis. The results revealed that <i>IbNBS75</i>, <i>IbNBS219</i>, and <i>IbNBS256</i> respond to stem nematode infection; <i>Ib­NBS240</i>, <i>IbNBS90</i>, and <i>IbNBS80</i> respond to cold stress, while <i>IbNBS208</i>, <i>IbNBS71</i>, and <i>IbNBS159</i> respond to 30% PEG treatment. We hope these results will provide new insights into the evolution of NBS-encoding genes in the sweetpotato genome and contribute to the molecular breeding of sweetpotato in the future.

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