Characterization of 3-isopropylmalate dehydrogenase from extremely halophilic archaeon Haloarcula japonica

2021 ◽  
Author(s):  
Shintaro Nagaoka ◽  
Noriko Sugiyama ◽  
Rie Yatsunami ◽  
Satoshi Nakamura
Keyword(s):  
Analytical Ultracentrifugation ◽  
Maximum Activity ◽  
Oxidative Decarboxylation ◽  
Halophilic Archaeon ◽  
Leucine Biosynthesis ◽  
First Report ◽  
Haloarcula Japonica ◽  
Extremely Halophilic Archaeon ◽  
Isopropylmalate Dehydrogenase

Abstract 3-Isopropylmalate dehydrogenase (IPMDH) catalyzes oxidative decarboxylation of (2R, 3S)-3-isopropylmalate to 2-oxoisocaproate in leucine biosynthesis. In this study, recombinant IPMDH (HjIPMDH) from an extremely halophilic archaeon, Haloarcula japonica TR-1, was characterized. Activity of HjIPMDH increased as KCl concentration increased, and the maximum activity was observed at 3.0 M KCl. Analytical ultracentrifugation revealed that HjIPMDH formed a homotetramer at high KCl concentrations, and it dissociated to a monomer at low KCl concentrations. Additionally, HjIPMDH was thermally stabilized by higher KCl concentrations. This is the first report on haloarchaeal IPMDH.

scholarly journals Gene Analysis, Expression, and Characterization of an Intracellular α-Amylase from the Extremely Halophilic Archaeon Haloarcula japonica

2013 ◽  
Vol 77 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Masahiko ONODERA ◽  
Rie YATSUNAMI ◽  
Wataru TSUKIMURA ◽  
Toshiaki FUKUI ◽  
Kaoru NAKASONE ◽  
...  
Keyword(s):  
Gene Analysis ◽  
Halophilic Archaeon ◽  
Haloarcula Japonica ◽  
Extremely Halophilic Archaeon

Characterization of a GlgC homolog from extremely halophilic archaeon Haloarcula japonica

2021 ◽  
Author(s):  
Rin Sueda ◽  
Kento Yoshida ◽  
Masahiko Onodera ◽  
Toshiaki Fukui ◽  
Rie Yatsunami ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Glycogen Synthesis ◽  
Recombinant Enzyme ◽  
Halophilic Archaeon ◽  
Haloarcula Japonica ◽  
Extremely Halophilic Archaeon

ABSTRACT Glycogen synthesis in bacteria is mainly organized by the products of glgB, glgC, and glgA genes comprising the widely known glg operon. On the genome of extremely halophilic archaeon Haloarcula japonica, there was a gene cluster analogous to the bacterial glg operon. In this study, we focused on a GlgC homolog of Ha. japonica, and its recombinant enzyme was prepared and characterized. The enzyme showed highest activity toward GTP and glucose-1-phosphate as substrates in the presence of 2.6 m KCl and predicted to be work as “GDP-glucose pyrophosphorylase” in Ha. japonica.

scholarly journals Protein complex formation in methionine chain-elongation and leucine biosynthesis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Qun Chen ◽  
Shweta Chhajed ◽  
Tong Zhang ◽  
Joseph M. Collins ◽  
Qiuying Pang ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Complete Characterization ◽  
Bimolecular Fluorescence Complementation ◽  
Chain Elongation ◽  
Substrate Channeling ◽  
Leucine Biosynthesis ◽  
Protein Complex Formation ◽  
Genes Encoding ◽  
Isopropylmalate Dehydrogenase

AbstractDuring the past two decades, glucosinolate (GLS) metabolic pathways have been under extensive studies because of the importance of the specialized metabolites in plant defense against herbivores and pathogens. The studies have led to a nearly complete characterization of biosynthetic genes in the reference plant Arabidopsis thaliana. Before methionine incorporation into the core structure of aliphatic GLS, it undergoes chain-elongation through an iterative three-step process recruited from leucine biosynthesis. Although enzymes catalyzing each step of the reaction have been characterized, the regulatory mode is largely unknown. In this study, using three independent approaches, yeast two-hybrid (Y2H), coimmunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC), we uncovered the presence of protein complexes consisting of isopropylmalate isomerase (IPMI) and isopropylmalate dehydrogenase (IPMDH). In addition, simultaneous decreases in both IPMI and IPMDH activities in a leuc:ipmdh1 double mutants resulted in aggregated changes of GLS profiles compared to either leuc or ipmdh1 single mutants. Although the biological importance of the formation of IPMI and IPMDH protein complexes has not been documented in any organisms, these complexes may represent a new regulatory mechanism of substrate channeling in GLS and/or leucine biosynthesis. Since genes encoding the two enzymes are widely distributed in eukaryotic and prokaryotic genomes, such complexes may have universal significance in the regulation of leucine biosynthesis.

scholarly journals Identification of carotenoids from the extremely halophilic archaeon Haloarcula japonica

2014 ◽  
Vol 5 ◽  
Author(s):  
Rie Yatsunami ◽  
Ai Ando ◽  
Ying Yang ◽  
Shinichi Takaichi ◽  
Masahiro Kohno ◽  
...  
Keyword(s):  
Halophilic Archaeon ◽  
Haloarcula Japonica ◽  
Extremely Halophilic Archaeon

scholarly journals Identification of Enzymes Homologous to Isocitrate Dehydrogenase That Are Involved in Coenzyme B and Leucine Biosynthesis in Methanoarchaea

2000 ◽  
Vol 182 (17) ◽  
pp. 5013-5016 ◽  
Author(s):  
David M. Howell ◽  
Marion Graupner ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Escherichia Coli ◽  
Enzymatic Activity ◽  
Isocitrate Dehydrogenase ◽  
Protein Product ◽  
Oxidative Decarboxylation ◽  
Gene Products ◽  
Methanococcus Jannaschii ◽  
Leucine Biosynthesis ◽  
Isopropylmalate Dehydrogenase ◽  
Coenzyme B

ABSTRACT Two putative Methanococcus jannaschii isocitrate dehydrogenase genes, MJ1596 and MJ0720, were cloned and overexpressed in Escherichia coli, and their gene products were tested for the ability to catalyze the NAD- and NADP-dependent oxidative decarboxylation of dl-threo-3-isopropylmalic acid, threo-isocitrate, erythro-isocitrate, and homologs of threo-isocitrate. Neither enzyme was found to use any of the isomers of isocitrate as a substrate. The protein product of the MJ1596 gene, designated AksF, catalyzed the NAD-dependent decarboxylation of intermediates in the biosynthesis of 7-mercaptoheptanoic acid, a moiety of methanoarchaeal coenzyme B (7-mercaptoheptanylthreonine phosphate). These intermediates included (−)-threo-isohomocitrate [(−)-threo-1-hydroxy-1,2,4-butanetricarboxylic acid], (−)-threo-iso(homo)2citrate [(−)-threo-1-hydroxy-1,2,5-pentanetricarboxylic acid], and (−)-threo-iso(homo)3citrate [(−)-threo-1-hydroxy-1,2,6-hexanetricarboxylic acid]. The protein product of MJ0720 was found to be α-isopropylmalate dehydrogenase (LeuB) and was found to catalyze the NAD-dependent decarboxylation of one isomer ofdl-threo-isopropylmalate to 2-ketoisocaproate; thus, it is involved in the biosynthesis of leucine. The AksF enzyme proved to be thermostable, losing only 10% of its enzymatic activity after heating at 100°C for 10 min, whereas the LeuB enzyme lost 50% of its enzymatic activity after heating at 80°C for 10 min.

scholarly journals Molecular cloning of transducer gene hjtB from extremely halophilic archaeon Haloarcula japonica

2005 ◽  
Vol 49 (1) ◽  
pp. 315-316
Author(s):  
Takayuki Kosaka ◽  
Takatoshi Ozawa ◽  
Rie Yatsunami ◽  
Toshiaki Fukui ◽  
Satoshi Nakamura
Keyword(s):  
Molecular Cloning ◽  
Halophilic Archaeon ◽  
Haloarcula Japonica ◽  
Extremely Halophilic Archaeon
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