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Chauhan SM, Poudel S, Rychel K, Lamoureux C, Yoo R, Al Bulushi T, Yuan Y, Palsson BO, Sastry AV. Machine Learning Uncovers a Data-Driven Transcriptional Regulatory Network for the Crenarchaeal Thermoacidophile Sulfolobus acidocaldarius. Front Microbiol 2021; 12:753521. [PMID: 34777307 PMCID: PMC8578740 DOI: 10.3389/fmicb.2021.753521] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/30/2021] [Indexed: 01/24/2023] Open
Abstract
Dynamic cellular responses to environmental constraints are coordinated by the transcriptional regulatory network (TRN), which modulates gene expression. This network controls most fundamental cellular responses, including metabolism, motility, and stress responses. Here, we apply independent component analysis, an unsupervised machine learning approach, to 95 high-quality Sulfolobus acidocaldarius RNA-seq datasets and extract 45 independently modulated gene sets, or iModulons. Together, these iModulons contain 755 genes (32% of the genes identified on the genome) and explain over 70% of the variance in the expression compendium. We show that five modules represent the effects of known transcriptional regulators, and hypothesize that most of the remaining modules represent the effects of uncharacterized regulators. Further analysis of these gene sets results in: (1) the prediction of a DNA export system composed of five uncharacterized genes, (2) expansion of the LysM regulon, and (3) evidence for an as-yet-undiscovered global regulon. Our approach allows for a mechanistic, systems-level elucidation of an extremophile's responses to biological perturbations, which could inform research on gene-regulator interactions and facilitate regulator discovery in S. acidocaldarius. We also provide the first global TRN for S. acidocaldarius. Collectively, these results provide a roadmap toward regulatory network discovery in archaea.
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Affiliation(s)
- Siddharth M. Chauhan
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Saugat Poudel
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Kevin Rychel
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Cameron Lamoureux
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Reo Yoo
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Tahani Al Bulushi
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Yuan Yuan
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Anand V. Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
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Liang YF, Long ZX, Zhang YJ, Luo CY, Yan LT, Gao WY, Li H. The chemical mechanisms of the enzymes in the branched-chain amino acids biosynthetic pathway and their applications. Biochimie 2021; 184:72-87. [PMID: 33607240 DOI: 10.1016/j.biochi.2021.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/04/2021] [Accepted: 02/10/2021] [Indexed: 12/27/2022]
Abstract
l-Valine, l-isoleucine, and l-leucine are three key proteinogenic amino acids, and they are also the essential amino acids required for mammalian growth, possessing important and to some extent, special physiological and biological functions. Because of the branched structures in their carbon chains, they are also named as branched-chain amino acids (BCAAs). This review will highlight the advance in studies of the enzymes involved in the biosynthetic pathway of BCAAs, concentrating on their chemical mechanisms and applications in screening herbicides and antibacterial agents. The uses of some of these enzymes in lab scale organic synthesis are also discussed.
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Affiliation(s)
- Yan-Fei Liang
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Zi-Xian Long
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Ya-Jian Zhang
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Cai-Yun Luo
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Le-Tian Yan
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Wen-Yun Gao
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China.
| | - Heng Li
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China.
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Popović MK, Senz M, Bader J, Skelac L, Schilf W, Bajpai R. Positive effect of reduced aeration rate on secretion of alpha-amylase and neutral proteases during pressurised fermentation of thermophilic Bacillus caldolyticus. N Biotechnol 2014; 31:141-9. [PMID: 24239980 DOI: 10.1016/j.nbt.2013.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/08/2013] [Accepted: 10/25/2013] [Indexed: 01/26/2023]
Abstract
The thermophilic microorganism Bacillus caldolyticus was incubated in laboratory scale stirred bioreactors under pressurised conditions at different aeration rates. Increased amounts of CO2/bicarbonate were solubilised under the chosen conditions. A reduction in aeration rate from 1 vvm to 0.1 vvm resulted in accumulation of CO2 and bicarbonate up to 126 mg l(-1) and 733 mg l(-1), respectively and also increased secretion of α-amylase and neutral proteases (increases of 123% and 52%, respectively). In this paper, the effect of reduced aeration rate on CO2/bicarbonate concentration and enzyme activities is presented. The selected fermentation conditions are closely related to those prevalent in large scale bioreactors and may offer the possibility of achieving high enzyme yields at reduced aeration costs on an industrial scale.
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Affiliation(s)
- M K Popović
- Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany.
| | - M Senz
- Institute of Biotechnology, University of Technology, Seestraße 13, 13353 Berlin, Germany
| | - J Bader
- Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany
| | - L Skelac
- Research Institute of Brewing, Seestraße 13, 13353 Berlin, Germany
| | - W Schilf
- Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany
| | - R Bajpai
- Chemical Engineering Department, University of Louisiana at Lafayette, Lafayette, LA 70508, USA
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4
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Drevland RM, Waheed A, Graham DE. Enzymology and evolution of the pyruvate pathway to 2-oxobutyrate in Methanocaldococcus jannaschii. J Bacteriol 2007; 189:4391-400. [PMID: 17449626 PMCID: PMC1913355 DOI: 10.1128/jb.00166-07] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The archaeon Methanocaldococcus jannaschii uses three different 2-oxoacid elongation pathways, which extend the chain length of precursors in leucine, isoleucine, and coenzyme B biosyntheses. In each of these pathways an aconitase-type hydrolyase catalyzes an hydroxyacid isomerization reaction. The genome sequence of M. jannaschii encodes two homologs of each large and small subunit that forms the hydrolyase, but the genes are not cotranscribed. The genes are more similar to each other than to previously characterized isopropylmalate isomerase or homoaconitase enzyme genes. To identify the functions of these homologs, the four combinations of subunits were heterologously expressed in Escherichia coli, purified, and reconstituted to generate the iron-sulfur center of the holoenzyme. Only the combination of MJ0499 and MJ1277 proteins catalyzed isopropylmalate and citramalate isomerization reactions. This pair also catalyzed hydration half-reactions using citraconate and maleate. Another broad-specificity enzyme, isopropylmalate dehydrogenase (MJ0720), catalyzed the oxidative decarboxylation of beta-isopropylmalate, beta-methylmalate, and d-malate. Combined with these results, phylogenetic analysis suggests that the pyruvate pathway to 2-oxobutyrate (an alternative to threonine dehydratase in isoleucine biosynthesis) evolved several times in bacteria and archaea. The enzymes in the isopropylmalate pathway of leucine biosynthesis facilitated the evolution of 2-oxobutyrate biosynthesis through the introduction of a citramalate synthase, either by gene recruitment or gene duplication and functional divergence.
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Affiliation(s)
- Randy M Drevland
- Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA
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Schloss JV, Magolda R, Emptage M. Synthesis of alpha-isopropylmalate, beta-isopropylmalate, and dimethylcitraconate. Methods Enzymol 1988; 166:92-6. [PMID: 3071725 DOI: 10.1016/s0076-6879(88)66014-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Sylvester SR, Stevens CM. Stereospecificity of the reductoisomerase-catalyzed step in the pathway of biosynthesis of valine and leucine. Biochemistry 1979; 18:4529-31. [PMID: 387071 DOI: 10.1021/bi00588a011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Bigelis R, Umbarger HE. Yeast alpha-isopropylmalate isomerase. Factors affecting stability and enzyme activity. J Biol Chem 1976. [DOI: 10.1016/s0021-9258(17)33378-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Rose IA. Enzyme reaction stereospecificity: a critical review. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1972; 1:33-57. [PMID: 4570577 DOI: 10.3109/10409237209102543] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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10
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Calvo JM, Bartholomew JC, Stieglitz BI. Fluorometric assay of enzymatic reactions involving acetyl Coenzyme A in aldol condensations. Anal Biochem 1969; 28:164-81. [PMID: 4889227 DOI: 10.1016/0003-2697(69)90168-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Stern JR, O'Brien RW. Oxidation D-malic and beta-alkylmalic acids wild-type and mutant strains of Salmonella typhimurium and by Aerobacter aerogenes. J Bacteriol 1969; 98:147-51. [PMID: 4889267 PMCID: PMC249916 DOI: 10.1128/jb.98.1.147-151.1969] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A mutant strain of Salmonella typhimurium (SL 1634 dml-51) capable of growth on d-malate as sole carbon source was shown to produce d-malic enzyme. This enzyme was absent in the parent wild-type strain which was unable to grow on d-malate. Growth of the mutant on d-malate also resulted in a greatly increased level of beta-isopropylmalic enzyme compared with its level in the wild-type strain grown on citrate or l-malate. The d-malic and beta-isopropylmalic enzymes, both of which catalyze a nicotinamide adenine dinucleotide- and Mg(++)-dependent oxidative decarboxylation of their respective substrates, were shown to be distinct enzymes by selective inhibition with erythro-dl-beta-hydroxyaspartate and by other methods. Cell extracts of the mutant strain also oxidized dl-beta-methyl-, dl-beta-ethyl-, dl-beta-propyl- and dl-betabeta-dimethylmalates, in order of decreasing activity. dl-beta-Methyl-malate was shown to be oxidized by both the d-malic and the beta-isopropylmalic enzymes, whereas the oxidation of the other beta-alkylmalates appeared to be effected exclusively by the beta-isopropylmalic enzyme. beta-Isopropylmalic enzyme activity was induced by d-malate but not by l-malate, showing that it behaved as a d-malictype enzyme. Growth of Aerobacter aerogenes on d-malate, which caused induction of d malic enzyme, resulted in only a small increase in the activity of beta-isopropylmalic enzyme.
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Rabin R, Salamon II, Bleiweis AS, Carlin J, Ajl SJ. Metabolism of ethylmalic acids by Pseudomonas aeruginosa. Biochemistry 1968; 7:377-88. [PMID: 4320440 DOI: 10.1021/bi00841a048] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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