Regulation of acetate and acetyl-CoA converting enzymes during growth on acetate and/or glucose in the halophilic archaeon<i>Haloarcula marismortui</i>

Bräsen, Christopher; Schönheit, Peter

doi:10.1016/j.femsle.2004.09.033

Cited by 27 publications

(14 citation statements)

References 25 publications

(37 reference statements)

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“…Both genes, encoding isocitrate lyase (SSO1333) and malate synthase (SSO1334), are consecutively colocalized in the genome but are separated by Ͼ450 bp and each exhibits its own promotor region including an upstream TATA box not forming an operon (291). The presence of the entire glyoxylate shunt in glucose-grown cells might be due to the reutilization of acetate excreted during exponential growth on glucose in the stationary phase, as also described for haloarchaea (357)(358)(359).…”

Section: Conversion Of Glycolaldehyde To Malatementioning

confidence: 80%

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Bräsen

Esser

Rauch

et al. 2014

Microbiol Mol Biol Rev

266

294

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SUMMARY The metabolism of Archaea , the third domain of life, resembles in its complexity those of Bacteria and lower Eukarya . However, this metabolic complexity in Archaea is accompanied by the absence of many “classical” pathways, particularly in central carbohydrate metabolism. Instead, Archaea are characterized by the presence of unique, modified variants of classical pathways such as the Embden-Meyerhof-Parnas (EMP) pathway and the Entner-Doudoroff (ED) pathway. The pentose phosphate pathway is only partly present (if at all), and pentose degradation also significantly differs from that known for bacterial model organisms. These modifications are accompanied by the invention of “new,” unusual enzymes which cause fundamental consequences for the underlying regulatory principles, and classical allosteric regulation sites well established in Bacteria and Eukarya are lost. The aim of this review is to present the current understanding of central carbohydrate metabolic pathways and their regulation in Archaea . In order to give an overview of their complexity, pathway modifications are discussed with respect to unusual archaeal biocatalysts, their structural and mechanistic characteristics, and their regulatory properties in comparison to their classic counterparts from Bacteria and Eukarya . Furthermore, an overview focusing on hexose metabolic, i.e., glycolytic as well as gluconeogenic, pathways identified in archaeal model organisms is given. Their energy gain is discussed, and new insights into different levels of regulation that have been observed so far, including the transcript and protein levels (e.g., gene regulation, known transcription regulators, and posttranslational modification via reversible protein phosphorylation), are presented.

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Section: Conversion Of Glycolaldehyde To Malatementioning

confidence: 80%

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Bräsen

Esser

Rauch

et al. 2014

Microbiol Mol Biol Rev

266

294

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“…The ecSCS has a high specificity for succinylCoA (22) but converts small aliphatic CoA esters (22) like ckcACD1 and other ACDs (2, 3, 5-7, 20, 21, 24, 37-39) as well. Interestingly, members of the ACD family are also able to transform aromatic CoA thioesters (3,24,39), although catalytic activity toward succinyl-CoA has only been described a few times (3,25,40). The high specificity of SCS enzymes for succinyl-CoA does make a lot of sense because this enzyme family is a central and, as such, an optimized element within the TCA cycle.…”

Section: Discussionmentioning

confidence: 99%

Structure of NDP-forming Acetyl-CoA synthetase ACD1 reveals a large rearrangement for phosphoryl transfer

Weisse

Faust

Schmidt

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The NDP-forming acyl-CoA synthetases (ACDs) catalyze the conversion of various CoA thioesters to the corresponding acids, conserving their chemical energy in form of ATP. The ACDs are the major energy-conserving enzymes in sugar and peptide fermentation of hyperthermophilic archaea. They are considered to be primordial enzymes of ATP synthesis in the early evolution of life. We present the first crystal structures, to our knowledge, of an ACD from the hyperthermophilic archaeon Candidatus Korachaeum cryptofilum. These structures reveal a unique arrangement of the ACD subunits alpha and beta within an α 2 β 2 -heterotetrameric complex. This arrangement significantly differs from other members of the superfamily. To transmit an activated phosphoryl moiety from the Ac-CoA binding site (within the alpha subunit) to the NDP-binding site (within the beta subunit), a distance of 51 Å has to be bridged. This transmission requires a larger rearrangement within the protein complex involving a 21-aa-long phosphohistidinecontaining segment of the alpha subunit. Spatial restraints of the interaction of this segment with the beta subunit explain the necessity for a second highly conserved His residue within the beta subunit. The data support the proposed four-step reaction mechanism of ACDs, coupling acyl-CoA thioesters with ATP synthesis. Furthermore, the determined crystal structure of the complex with bound Ac-CoA allows first insight, to our knowledge, into the determinants for acyl-CoA substrate specificity. The composition and size of loops protruding into the binding pocket of acyl-CoA are determined by the individual arrangement of the characteristic subdomains.X-ray structure | metabolic energy conversion | protein dynamics | acyl-coenzyme A thioester | superfamily N DP-forming acyl-CoA synthetases (ACDs) catalyze the conversion of acyl-CoA thioesters to the corresponding acids and couple this reaction with the synthesis of ATP via the mechanism of substrate-level phosphorylation. ACDs have been studied in detail in hyperthermophilic archaea, where they function as the major energy-conserving enzymes in the course of anaerobic sugar and peptide fermentation (1-4). It is believed that ACDs represent a primordial mechanism of ATP synthesis in the early evolution of life. ACDs were found in all acetate (acid)-forming archaea (5, 6) and in the eukaryotic parasitic protists Entamoeba histolytica (7) and Giardia lamblia (8), but they have not been found in acetate-forming bacteria. In bacteria, with the exception of Chloroflexus (9), the conversion of inorganic phosphate and the thioester acetyl (Ac)-CoA to acetate and ATP is catalyzed by two enzymes, phosphate Ac-transferase and acetate kinase (10).

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“…Brasen and Schonheit Schonheit 2001, Brasen andSchonheit 2004) During growth on glucose, these halophiles excreted acetate into the media and exhibited ADP-forming acetyl-CoA synthetase activity (ADP-ACS; acetyl-CoA + ADP + P i ↔ acetate + ATP + CoA) but not ACS activity. Upon entry into stationary phase, ACS activity was induced and the excreted acetate was consumed.…”

Section: Discussionmentioning

confidence: 99%

AMP-forming acetyl-CoA synthetases in Archaea show unexpected diversity in substrate utilization

Ingram‐Smith

Smith

2006

Archaea

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Summary Adenosine monophosphate (AMP)-forming acetyl-CoA synthetase (ACS; acetate:CoA ligase (AMP-forming), EC 6.2.1.1) is a key enzyme for conversion of acetate to acetyl-CoA, an essential intermediate at the junction of anabolic and catabolic pathways. Phylogenetic analysis of putative short and medium chain acyl-CoA synthetase sequences indicates that the ACSs form a distinct clade from other acyl-CoA synthetases. Within this clade, the archaeal ACSs are not monophyletic and fall into three groups composed of both bacterial and archaeal sequences. Kinetic analysis of two archaeal enzymes, an ACS from Methanothermobacter thermautotrophicus (designated as MT-ACS1) and an ACS from Archaeoglobus fulgidus (designated as AF-ACS2), revealed that these enzymes have very different properties. MT-ACS1 has nearly 11-fold higher affinity and 14-fold higher catalytic efficiency with acetate than with propionate, a property shared by most ACSs. However, AF-ACS2 has only 2.3-fold higher affinity and catalytic efficiency with acetate than with propionate. This enzyme has an affinity for propionate that is almost identical to that of MT-ACS1 for acetate and nearly tenfold higher than the affinity of MT-ACS1 for propionate. Furthermore, MT-ACS1 is limited to acetate and propionate as acyl substrates, whereas AF-ACS2 can also utilize longer straight and branched chain acyl substrates. Phylogenetic analysis, sequence alignment and structural modeling suggest a molecular basis for the altered substrate preference and expanded substrate range of AF-ACS2 versus MT-ACS1.

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Regulation of acetate and acetyl-CoA converting enzymes during growth on acetate and/or glucose in the halophilic archaeonHaloarcula marismortui

Cited by 27 publications

References 25 publications

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

Structure of NDP-forming Acetyl-CoA synthetase ACD1 reveals a large rearrangement for phosphoryl transfer

AMP-forming acetyl-CoA synthetases in Archaea show unexpected diversity in substrate utilization

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