scholarly journals GapMind: Automated Annotation of Amino Acid Biosynthesis

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Morgan N. Price ◽  
Adam M. Deutschbauer ◽  
Adam P. Arkin
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Building Blocks ◽  
Amino Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Alternative Pathways ◽  
Automated Annotation ◽  
A Genome ◽  
Minimal Media

ABSTRACT GapMind is a Web-based tool for annotating amino acid biosynthesis in bacteria and archaea (http://papers.genomics.lbl.gov/gaps). GapMind incorporates many variant pathways and 130 different reactions, and it analyzes a genome in just 15 s. To avoid error-prone transitive annotations, GapMind relies primarily on a database of experimentally characterized proteins. GapMind correctly handles fusion proteins and split proteins, which often cause errors for best-hit approaches. To improve GapMind’s coverage, we examined genetic data from 35 bacteria that grow in defined media without amino acids, and we filled many gaps in amino acid biosynthesis pathways. For example, we identified additional genes for arginine synthesis with succinylated intermediates in Bacteroides thetaiotaomicron, and we propose that Dyella japonica synthesizes tyrosine from phenylalanine. Nevertheless, for many bacteria and archaea that grow in minimal media, genes for some steps still cannot be identified. To help interpret potential gaps, GapMind checks if they match known gaps in related microbes that can grow in minimal media. GapMind should aid the identification of microbial growth requirements. IMPORTANCE Many microbes can make all of the amino acids (the building blocks of proteins). In principle, we should be able to predict which amino acids a microbe can make, and which it requires as nutrients, by checking its genome sequence for all of the necessary genes. However, in practice, it is difficult to check for all of the alternative pathways. Furthermore, new pathways and enzymes are still being discovered. We built an automated tool, GapMind, to annotate amino acid biosynthesis in bacterial and archaeal genomes. We used GapMind to list gaps: cases where a microbe makes an amino acid but a complete pathway cannot be identified in its genome. We used these gaps, together with data from mutants, to identify new pathways and enzymes. However, for most bacteria and archaea, we still do not know how they can make all of the amino acids.

scholarly journals GapMind: Automated annotation of amino acid biosynthesis

2019 ◽  
Author(s):  
Morgan Price ◽  
Adam M. Deutschbauer ◽  
Adam P. Arkin
Keyword(s):  
Amino Acid ◽  
Fusion Proteins ◽  
Genetic Data ◽  
Amino Acid Biosynthesis ◽  
Bacteroides Thetaiotaomicron ◽  
Acid Biosynthesis ◽  
Web Based ◽  
Automated Annotation ◽  
A Genome ◽  
Minimal Media

AbstractGapMind is a web-based tool for annotating amino acid biosynthesis in bacteria and archaea (http://papers.genomics.lbl/gov/gaps). GapMind incorporates many variant pathways and 130 different reactions, and it analyzes a genome in just 15 seconds. To avoid error-prone “transitive” annotations, GapMind relies primarily on a database of experimentally-characterized proteins. GapMind correctly handles fusion proteins and split proteins, which often cause errors for “best hit” approaches. To improve GapMind’s coverage, we examined genetic data from 35 bacteria that grow in minimal media and we filled many gaps in amino acid biosynthesis pathways. For example, we identified additional genes for arginine synthesis with succinylated intermediates in Bacteroides thetaiotaomicron and we propose that Dyella japonica synthesizes tyrosine from phenylalanine. Nevertheless, for many bacteria and archaea that grow in minimal media, genes for some steps still cannot be identified. If a potential gap in the genome of interest is also a gap in a related microbe that can grow in minimal media, GapMind marks the gap as “known.”

scholarly journals The TK0271 Protein Activates Transcription of Aromatic Amino Acid Biosynthesis Genes in the Hyperthermophilic Archaeon Thermococcus kodakarensis

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Yasuyuki Yamamoto ◽  
Tamotsu Kanai ◽  
Tsuyoshi Kaneseki ◽  
Haruyuki Atomi
Keyword(s):  
Amino Acids ◽  
Transcriptional Regulation ◽  
Amino Acid ◽  
Aromatic Amino Acid ◽  
Amino Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Hyperthermophilic Archaeon ◽  
Thermococcus Kodakarensis ◽  
Aromatic Amino Acid Biosynthesis

ABSTRACT TrpY from Methanothermobacter thermautotrophicus is a regulator that inhibits transcription of the Trp biosynthesis (trp) operon. Here, we show that the TrpY homolog in Thermococcus kodakarensis is not involved in such regulation. There are 87 genes on the T. kodakarensis genome predicted to encode transcriptional regulators (TRs). By screening for TRs that specifically bind to the promoter of the trp operon of T. kodakarensis, we identified TK0271. The gene resides in the aro operon, responsible for the biosynthesis of chorismate, a precursor for Trp, Tyr, and Phe. TK0271 was expressed in Escherichia coli, and the protein, here designated Tar (Thermococcales aromatic amino acid regulator), was purified. Tar specifically bound to the trp promoter with a dissociation constant (Kd) value of approximately 5 nM. Tar also bound to the promoters of the Tyr/Phe biosynthesis (tyr-phe) and aro operons. The protein recognized a palindromic sequence (TGGACA-N8-TGTCCA) conserved in these promoters. In vitro transcription assays indicated that Tar activates transcription from all three promoters. We cultivated T. kodakarensis in amino acid-based medium and found that transcript levels of the trp, tyr-phe, and aro operons increased in the absence of Trp, Tyr, or Phe. We further constructed a TK0271 gene disruption strain (ΔTK0271). Growth of ΔTK0271 was similar to that of the host strain in medium including Trp, Tyr, and Phe but was significantly impaired in the absence of any one of these amino acids. The results suggest that Tar is responsible for the transcriptional activation of aromatic amino acid biosynthesis genes in T. kodakarensis. IMPORTANCE The mechanisms of transcriptional regulation in archaea are still poorly understood. In this study, we identified a transcriptional regulator in the hyperthermophilic archaeon Thermococcus kodakarensis that activates the transcription of three operons involved in the biosynthesis of aromatic amino acids. The study represents one of only a few that identifies a regulator in Archaea that activates transcription. The results also imply that transcriptional regulation of genes with the same function is carried out by diverse mechanisms in the archaea, depending on the lineage.

scholarly journals A Newly Determined Member of the meso-Diaminopimelate Dehydrogenase Family with a Broad Substrate Spectrum

2017 ◽  
Vol 83 (11) ◽  
Author(s):  
Xiuzhen Gao ◽  
Zheng Zhang ◽  
Ya'nan Zhang ◽  
Ying Li ◽  
Heng Zhu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Quaternary Structure ◽  
Amino Acid Biosynthesis ◽  
Type I ◽  
Type Ii ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Keto Acids ◽  
Substrate Spectrum

ABSTRACT meso-Diaminopimelate dehydrogenase (meso-DAPDH) from Symbiobacterium thermophilum (StDAPDH) is the first member of the meso-DAPDH family known to catalyze the asymmetric reductive amination of 2-keto acids to produce d-amino acids. It is important to understand the catalytic mechanisms of StDAPDH and other enzymes in this family. In this study, based on an evolutionary analysis and examination of catalytic activity, the meso-DAPDH enzymes can be divided into two types. Type I showed highly preferable activity toward meso-diaminopimelate (meso-DAP), and type II exhibited obviously reversible amination activity with a broad substrate spectrum. StDAPDH belongs to type II. A quaternary structure analysis revealed that insertions/deletions (indels) and a loss of quaternary structure resulted in divergence among members of the meso-DAPDH family. A structure alignment of StDAPDH with a representative of type I, the meso-DAPDH from Corynebacterium glutamicum (CgDAPDH), indicated that they had the same folding. Based on sequence and conservation analyses, two amino acid residues of StDAPDH, R35 and R71, were found to be highly conserved within type II while also distinct from each other between the subtypes. Site mutagenesis studies identified R71 as a substrate preference-related residue of StDAPDH, which may serve as an indicator of the amination preference of type II. These results deepen the present understanding of the meso-DAPDH family and provide a solid foundation for the discovery and engineering of meso-DAPDH for d-amino acid biosynthesis. IMPORTANCE The l-form of amino acids is typically more abundant than the d-form. However, the d-form has many important pharmaceutical applications. meso-Diaminopimelate dehydrogenase (meso-DAPDH) from Symbiobacterium thermophilum (StDAPDH) was the first member of meso-DAPDH known to catalyze the amination of 2-keto acids to produce d-amino acids. Accordingly, we analyzed the evolution of meso-DAPDH proteins and found that they form two groups, i.e., type I proteins, which show high preference toward meso-diaminopimelate (meso-DAP), and type II proteins, which show a broad substrate spectrum. We examined the differences in sequence, ternary structure, and quaternary structure to determine the mechanisms underlying the functional differences between the type I and type II lineages. These results will facilitate the identification of additional meso-DAPDHs and may provide guidance to protein engineering studies for d-amino acid biosynthesis.

scholarly journals DksA-Dependent Resistance of Salmonella enterica Serovar Typhimurium against the Antimicrobial Activity of Inducible Nitric Oxide Synthase

2012 ◽  
Vol 80 (4) ◽  
pp. 1373-1380 ◽  
Author(s):  
Calvin A. Henard ◽  
Andrés Vázquez-Torres
Keyword(s):  
Nitric Oxide ◽  
Amino Acids ◽  
Amino Acid ◽  
Rna Polymerase ◽  
Amino Acid Biosynthesis ◽  
Biosynthetic Pathways ◽  
Innate Response ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTIn coordination with the ppGpp alarmone, the RNA polymerase regulatory protein DksA controls the stringent response of eubacteria, negatively regulating transcription of translational machinery and directly activating amino acid promoters andde novoamino acid biosynthesis. Given the effects of nitric oxide (NO) on amino acid biosynthetic pathways and the intimate relationship of DksA with amino acid synthesis and transport, we tested whether DksA contributes to the resistance ofSalmonellato reactive nitrogen species (RNS). Our studies show that the zinc finger predicted to position DksA in the secondary channel of the RNA polymerase is essential for the resistance ofSalmonella entericaserovar Typhimurium to RNS in a murine model of systemic salmonellosis. Despite exhibiting auxotrophies for various amino acids, ΔdksAmutantSalmonellastrains regain virulence in mice lacking inducible NO synthase (iNOS). DksA is also important for growth of this intracellular pathogen in the presence of NO congeners generated by iNOS during the innate response of murine macrophages. Accordingly,dksAmutantSalmonellastrains are hypersusceptible to chemically generated NO, a phenotype that can be prevented by adding amino acids. The DksA-dependent antinitrosative defenses do not rely on the Hmp flavohemoprotein that detoxifies NO to NO3−and appear to operate independently of the ppGpp alarmone. Our investigations are consistent with a model by which NO produced in the innate response toSalmonellaexerts considerable pressure on amino acid biosynthesis. The cytotoxicity of NO againstSalmonellaamino acid biosynthetic pathways is antagonized in great part by the DksA-dependent regulation of amino acid biosynthesis and transport.

scholarly journals PII Signal Transduction Protein GlnK Alleviates Feedback Inhibition of N-Acetyl-L-Glutamate Kinase by L-Arginine in Corynebacterium glutamicum

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Meijuan Xu ◽  
Mi Tang ◽  
Jiamin Chen ◽  
Taowei Yang ◽  
Xian Zhang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Corynebacterium Glutamicum ◽  
Feedback Inhibition ◽  
Amino Acid Biosynthesis ◽  
Arginine Biosynthesis ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Pii Protein

ABSTRACT PII signal transduction proteins are ubiquitous and highly conserved in bacteria, archaea, and plants and play key roles in controlling nitrogen metabolism. However, research on biological functions and regulatory targets of PII proteins remains limited. Here, we illustrated experimentally that the PII protein Corynebacterium glutamicum GlnK (CgGlnK) increased l-arginine yield when glnK was overexpressed in Corynebacterium glutamicum. Data showed that CgGlnK regulated l-arginine biosynthesis by upregulating the expression of genes of the l-arginine metabolic pathway and interacting with N-acetyl-l-glutamate kinase (CgNAGK), the rate-limiting enzyme in l-arginine biosynthesis. Further assays indicated that CgGlnK contributed to alleviation of the feedback inhibition of CgNAGK caused by l-arginine. In silico analysis of the binding interface of CgGlnK-CgNAGK suggested that the B and T loops of CgGlnK mainly interacted with C and N domains of CgNAGK. Moreover, F11, R47, and K85 of CgGlnK were identified as crucial binding sites that interact with CgNAGK via hydrophobic interaction and H bonds, and these interactions probably had a positive effect on maintaining the stability of the complex. Collectively, this study reveals PII-NAGK interaction in nonphotosynthetic microorganisms and further provides insights into the regulatory mechanism of PII on amino acid biosynthesis in corynebacteria. IMPORTANCE Corynebacteria are safe industrial producers of diverse amino acids, including l-glutamic acid and l-arginine. In this study, we showed that PII protein GlnK played an important role in l-glutamic acid and l-arginine biosynthesis in C. glutamicum. Through clarifying the molecular mechanism of CgGlnK in l-arginine biosynthesis, the novel interaction between CgGlnK and CgNAGK was revealed. The alleviation of l-arginine inhibition of CgNAGK reached approximately 48.21% by CgGlnK addition, and the semi-inhibition constant of CgNAGK increased 1.4-fold. Furthermore, overexpression of glnK in a high-yield l-arginine-producing strain and fermentation of the recombinant strain in a 5-liter bioreactor led to a remarkably increased production of l-arginine, 49.978 g/liter, which was about 22.61% higher than that of the initial strain. In conclusion, this study provides a new strategy for modifying amino acid biosynthesis in C. glutamicum.

Effects of an Electric Field of Sinusoidal Waves on the Amino Acid Biosynthesis by Azotobacter

1980 ◽  
Vol 35 (3-4) ◽  
pp. 258-261
Author(s):  
A. Martin Gonzalez ◽  
M. T. Izquierdo
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Amino Acid ◽  
Electric Field ◽  
Electric Fields ◽  
Culture Medium ◽  
Azotobacter Vinelandii ◽  
Amino Acid Biosynthesis ◽  
Medium Composition ◽  
Acid Biosynthesis

Abstract Electric Field Electric fields of sinusoidal waves have been applied in cultures of Azotobacter vinelandii, with potentials between 0 V and 10 V, intensities from 0 mA to 16 mA and frequencies between 5 Hz and 200 KHz. The influence of the electric field of sinusoidal waves on the nitrogen fixation on the post­ culture medium composition has a maximum at 5 V, 8 mA and 20 Hz. The rate of synthesis of specific amino acids by Azotobacter depends on the frequency and potential of the electric field applied. The concentration of each amino acid present in the post-culture medium is increased according to the electric field employed and the amino acid biosynthesis in culture medium is activated during the first days of incubation.

The Gcn2–eIF2α pathway connects iron and amino acid homeostasis in Saccharomyces cerevisiae

2018 ◽  
Vol 475 (8) ◽  
pp. 1523-1534 ◽  
Author(s):  
Marcos Caballero-Molada ◽  
María D. Planes ◽  
Helena Benlloch ◽  
Sergio Atares ◽  
Miguel A. Naranjo ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Iron Content ◽  
Amino Acid Biosynthesis ◽  
Initiation Factor ◽  
Acid Biosynthesis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Iron Sulfur ◽  
Amino Acid Homeostasis

In eukaryotic cells, amino acid biosynthesis is feedback-inhibited by amino acids through inhibition of the conserved protein kinase Gcn2. This decreases phosphorylation of initiation factor eIF2α, resulting in general activation of translation but inhibition of translation of mRNA for transcription factor (TF) Gcn4 in yeast or ATF4 in mammals. These TFs are positive regulators of amino acid biosynthetic genes. As several enzymes of amino acid biosynthesis contain iron–sulfur clusters (ISCs) and iron excess is toxic, iron and amino acid homeostasis should be co-ordinated. Working with the yeast Saccharomyces cerevisiae, we found that amino acid supplementation down-regulates expression of genes for iron uptake and decreases intracellular iron content. This cross-regulation requires Aft1, the major TF activated by iron scarcity, as well as Gcn2 and phosphorylatable eIF2α but not Gcn4. A mutant with constitutive activity of Gcn2 (GCN2c) shows less repression of iron transport genes by amino acids and increased nuclear localization of Aft1 in an iron-poor medium, and increases iron content in this medium. As Aft1 is activated by depletion of mitochondrial ISCs, it is plausible that the Gcn2–eIF2α pathway inhibits the formation of these complexes. Accordingly, the GCN2c mutant has strongly reduced activity of succinate dehydrogenase, an iron–sulfur mitochondrial enzyme, and is unable to grow in media with very low iron or with galactose instead of glucose, conditions where formation of ISCs is specially needed. This mechanism adjusts the uptake of iron to the needs of amino acid biosynthesis and expands the list of Gcn4-independent activities of the Gcn2–eIF2α regulatory system.

scholarly journals Suppression of a Thermosensitive zipA Cell Division Mutant by Altering Amino Acid Metabolism

2017 ◽  
Vol 200 (2) ◽  
Author(s):  
Daniel E. Vega ◽  
William Margolin
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Cytoplasmic Membrane ◽  
Amino Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Content Type ◽  
Cell Division Protein

ABSTRACTZipA is essential for cell division inEscherichia coli, acting early in the process to anchor polymers of FtsZ to the cytoplasmic membrane. Along with FtsA, FtsZ and ZipA form a proto-ring at midcell that recruits additional proteins to eventually build the division septum. Cells carrying the thermosensitivezipA1allele divide fairly normally at 30°C in rich medium but cease dividing at temperatures above 34°C, forming long filaments. In a search for suppressors of thezipA1allele, we found that deletions of specific genes involved in amino acid biosynthesis could partially rescue cell growth and division at 34°C or 37°C but not at 42°C. Notably, although a diverse group of amino acid biosynthesis gene deletions could partially rescue the growth ofzipA1cells at 34°C, only deletions of genes related to the biosynthesis of threonine, glycine, serine, and methionine could rescue growth at 37°C. Adding exogenous pyridoxal 5-phosphate (PLP), a cofactor for many of the enzymes affected by this study, partially suppressedzipA1mutant thermosensitivity. For many of the deletions, PLP had an additive rescuing effect on thezipA1mutant. Moreover, added PLP partially suppressed the thermosensitivity offtsQandftsKmutants and weakly suppressed anftsImutant, but it failed to suppressftsAorftsZthermosensitive mutants. Along with the ability of a deletion ofmetCto partially suppress theftsKmutant, our results suggest that perturbations of amino acid metabolic pathways, particularly those that redirect the flow of carbon away from the synthesis of threonine, glycine, or methionine, are able to partially rescue some cell division defects.IMPORTANCECell division of bacteria, such asEscherichia coli, is essential for their successful colonization. It is becoming increasingly clear that nutritional status and central metabolism can affect bacterial size and shape; for example, a metabolic enzyme (OpgH) can moonlight as a regulator of FtsZ, an essential cell division protein. Here, we demonstrate a link between amino acid metabolism and ZipA, another essential cell division protein that binds directly to FtsZ and tethers it to the cytoplasmic membrane. Our evidence suggests that altering flux through the methionine-threonine-glycine-serine pathways and supplementing with the enzyme cofactor pyridoxal-5-phosphate can partially compensate for an otherwise lethal defect in ZipA, as well as several other cell division proteins.

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