Functional characterization of the three genes encoding 1-deoxy-D-xylulose 5-phosphate synthase in maize

2011 ◽  
Vol 62 (6) ◽  
pp. 2023-2038 ◽  
Author(s):  
E. Cordoba ◽  
H. Porta ◽  
A. Arroyo ◽  
C. San Roman ◽  
L. Medina ◽  
...  
2003 ◽  
Vol 185 (24) ◽  
pp. 7193-7201 ◽  
Author(s):  
Jesse D. Woodson ◽  
Carmen L. Zayas ◽  
Jorge C. Escalante-Semerena

ABSTRACT The ability of archaea to salvage cobinamide has been under question because archaeal genomes lack orthologs to the bacterial nucleoside triphosphate:5′-deoxycobinamide kinase enzyme (cobU in Salmonella enterica). The latter activity is required for cobinamide salvaging in bacteria. This paper reports evidence that archaea salvage cobinamide from the environment by using a pathway different from the one used by bacteria. These studies demanded the functional characterization of two genes whose putative function had been annotated based solely on their homology to the bacterial genes encoding adenosylcobyric acid and adenosylcobinamide-phosphate synthases (cbiP and cbiB, respectively) of S. enterica. A cbiP mutant strain of the archaeon Halobacterium sp. strain NRC-1 was auxotrophic for adenosylcobyric acid, a known intermediate of the de novo cobamide biosynthesis pathway, but efficiently salvaged cobinamide from the environment, suggesting the existence of a salvaging pathway in this archaeon. A cbiB mutant strain of Halobacterium was auxotrophic for adenosylcobinamide-GDP, a known de novo intermediate, and did not salvage cobinamide. The results of the nutritional analyses of the cbiP and cbiB mutants suggested that the entry point for cobinamide salvaging is adenosylcobyric acid. The data are consistent with a salvaging pathway for cobinamide in which an amidohydrolase enzyme cleaves off the aminopropanol moiety of adenosylcobinamide to yield adenosylcobyric acid, which is converted by the adenosylcobinamide-phosphate synthase enzyme to adenosylcobinamide-phosphate, a known intermediate of the de novo biosynthetic pathway. The existence of an adenosylcobinamide amidohydrolase enzyme would explain the lack of an adenosylcobinamide kinase in archaea.


2006 ◽  
Vol 26 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Si Sun ◽  
Jo Han Gan ◽  
Jennifer J. Paynter ◽  
Stephen J. Tucker

Our understanding of the mammalian inwardly rectifying family of K+ channels (Kir family) has recently been advanced by X-ray crystal structures of two homologous prokaryotic orthologs (KirBac1.1 and KirBac3.1). However, the functional properties of these KirBac channels are still poorly understood. To address this problem, we cloned and characterized genes encoding KirBac orthologs from a wide variety of different prokaryotes and a simple unicellular eukaryote. The functional properties of these KirBacs were then examined by growth complementation in a K+ uptake-deficient strain of Escherichia coli (TK2420). Whereas some KirBac genes exhibited robust growth complementation, others either did not complement or showed temperature-dependent complementation including KirBac1.1 and KirBac3.1. In some cases, KirBac expression was also toxic to the growth of E. coli. The KirBac family exhibited a range of sensitivity to the K+ channel blockers Ba2+ and Cs+ as well as differences in their ability to grow on very low-K+ media, thus demonstrating major differences in their permeation properties. These results reveal the existence of a functionally diverse superfamily of microbial KirBac genes and present an excellent resource for the structural and functional analysis of this class of K+ channels. Furthermore, the complementation assay used in this study provides a simple and robust method for the functional characterization of a range of prokaryotic K+ channels that are difficult to study by traditional methods.


Planta ◽  
2018 ◽  
Vol 248 (5) ◽  
pp. 1121-1141 ◽  
Author(s):  
Papri Basak ◽  
Shiny Sangma ◽  
Abhishek Mukherjee ◽  
Tanushree Agarwal ◽  
Sonali Sengupta ◽  
...  

2008 ◽  
Vol 190 (19) ◽  
pp. 6318-6329 ◽  
Author(s):  
Maria Billini ◽  
Kostas Stamatakis ◽  
Vicky Sophianopoulou

ABSTRACT Synechococcus elongatus strain PCC 7942 is an alkaliphilic cyanobacterium that tolerates a relatively high salt concentration as a freshwater microorganism. Its genome sequence revealed seven genes, nha1 to nha7 (syn_pcc79420811, syn_pcc79421264, syn_pcc7942359, syn_pcc79420546, syn_pcc79420307, syn_pcc79422394, and syn_pcc79422186), and the deduced amino acid sequences encoded by these genes are similar to those of Na+/H+ antiporters. The present work focused on molecular and functional characterization of these nha genes encoding Na+/H+ antiporters. Our results show that of the nha genes expressed in Escherichia coli, only nha3 complemented the deficient Na+/H+ antiporter activity of the Na+-sensitive TO114 recipient strain. Moreover, two of the cyanobacterial strains with separate disruptions in the nha genes (Δnha1, Δnha2, Δnha3, Δnha4, Δnha5, and Δnha7) had a phenotype different from that of the wild type. In particular, ΔnhA3 cells showed a high-salt- and alkaline-pH-sensitive phenotype, while Δnha2 cells showed low salt and alkaline pH sensitivity. Finally, the transcriptional profile of the nha1 to nha7 genes, monitored using the real-time PCR technique, revealed that the nha6 gene is upregulated and the nha1 gene is downregulated under certain environmental conditions.


2021 ◽  
Vol 114 ◽  
pp. 103838
Author(s):  
Yunpeng Cao ◽  
Tao Fang ◽  
Mingli Fan ◽  
Lei Wang ◽  
Caiyun Lv ◽  
...  

2021 ◽  
Vol 66 (3) ◽  
pp. 161-169
Author(s):  
Huyen Tran Thi Thanh ◽  
Hong La Viet ◽  
Quynh Le Thi Ngoc ◽  
Thuy Pham Chau ◽  
Quyen Ha Thi ◽  
...  

Nuclear factor-Y (NF-Y) has been known as one of the plant-specific transcription factors that play key roles in numerous biological processes during the growth and development of plant species. In this study, a comprehensive analysis of NF-YC sub-units in grain amaranth (Amaranthus hypochondriacus) was carried out based on the bioinformatics approaches. Firstly, a total of five members of the NF-YC sub-units was reported in the grain amaranth. Its structural analyses revealed that the NF-YC sub-units were variable in physic-chemical properties, like protein sizes, molecular masses, isoelectric point, instability index, and grand average of hydropathy. Of our interest, the expression profiles of genes encoding NF-YC sub-units in various tissues\organs during the growth and development of grain amaranth. We found that three genes, including AhNF-YC01, AhNF-YC04, and AhNF-YC05 were highly expressed in leaf, root, floral, immature seed, and stem tissues. Interestingly, AhNF-YC05 was exclusively expressed in leaf and stem tissues. Taken together, our study could provide a solid understanding for further functional characterization of genes encoding NF-YC sub-units in grain amaranth.


2008 ◽  
Vol 412 (3) ◽  
pp. 485-493 ◽  
Author(s):  
Xavier Robellet ◽  
Michel Flipphi ◽  
Sylvine Pégot ◽  
Andrew P. MacCabe ◽  
Christian Vélot

In a previous study, alcS, a gene of the Aspergillus nidulans alc cluster, was shown to encode a protein that belongs to the GPR1/FUN34/YaaH membrane protein family. BLAST screening of the A. nidulans genome data identified additional genes encoding hypothetical proteins that could belong to this family. In this study we report the functional characterization of one of them, AN5226. Its expression is induced by ethanol and ethyl acetate (two inducers of the alc genes) and is mediated by the specific transcriptional activator of genes of the acetate-utilization pathway FacB. Growth of a null mutant (ΔAN5226) is notably affected when acetate is used as sole carbon source at low concentration and in a high pH medium, i.e. when protonated acetate, the form that can enter the cell by passive diffusion, is present in low amounts. Consistently, expression of AN5226 is also induced by acetate, but only when the latter is present at low concentrations. 14C-labelled acetate uptake experiments using germinating conidia demonstrate an essential role for AN5226 in mediated acetate transport. To our knowledge this report is the first to provide evidence for the identification of an acetate transporter in filamentous fungi. We have designated AN5226 as acpA (for acetate permease A).


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