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Funke FJ, Schlee S, Sterner R. Validation of aminodeoxychorismate synthase and anthranilate synthase as novel targets for bispecific antibiotics inhibiting conserved protein-protein interactions. Appl Environ Microbiol 2024; 90:e0057224. [PMID: 38700332 PMCID: PMC11107160 DOI: 10.1128/aem.00572-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/08/2024] [Indexed: 05/05/2024] Open
Abstract
Multi-resistant bacteria are a rapidly emerging threat to modern medicine. It is thus essential to identify and validate novel antibacterial targets that promise high robustness against resistance-mediating mutations. This can be achieved by simultaneously targeting several conserved function-determining protein-protein interactions in enzyme complexes from prokaryotic primary metabolism. Here, we selected two evolutionary related glutamine amidotransferase complexes, aminodeoxychorismate synthase and anthranilate synthase, that are required for the biosynthesis of folate and tryptophan in most prokaryotic organisms. Both enzymes rely on the interplay of a glutaminase and a synthase subunit that is conferred by a highly conserved subunit interface. Consequently, inhibiting subunit association in both enzymes by one competing bispecific inhibitor has the potential to suppress bacterial proliferation. We comprehensively verified two conserved interface hot-spot residues as potential inhibitor-binding sites in vitro by demonstrating their crucial role in subunit association and enzymatic activity. For in vivo target validation, we generated genomically modified Escherichia coli strains in which subunit association was disrupted by modifying these central interface residues. The growth of such strains was drastically retarded on liquid and solid minimal medium due to a lack of folate and tryptophan. Remarkably, the bacteriostatic effect was observed even in the presence of heat-inactivated human plasma, demonstrating that accessible host metabolite concentrations do not compensate for the lack of folate and tryptophan within the tested bacterial cells. We conclude that a potential inhibitor targeting both enzyme complexes will be effective against a broad spectrum of pathogens and offer increased resilience against antibiotic resistance. IMPORTANCE Antibiotics are indispensable for the treatment of bacterial infections in human and veterinary medicine and are thus a major pillar of modern medicine. However, the exposure of bacteria to antibiotics generates an unintentional selective pressure on bacterial assemblies that over time promotes the development or acquisition of resistance mechanisms, allowing pathogens to escape the treatment. In that manner, humanity is in an ever-lasting race with pathogens to come up with new treatment options before resistances emerge. In general, antibiotics with novel modes of action require more complex pathogen adaptations as compared to chemical derivates of existing entities, thus delaying the emergence of resistance. In this contribution, we use modified Escherichia coli strains to validate two novel targets required for folate and tryptophan biosynthesis that can potentially be targeted by one and the same bispecific protein-protein interaction inhibitor and promise increased robustness against bacterial resistances.
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Affiliation(s)
- Franziska Jasmin Funke
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sandra Schlee
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
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2
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Klem H, Alegre-Requena JV, Paton RS. Catalytic Effects of Active Site Conformational Change in the Allosteric Activation of Imidazole Glycerol Phosphate Synthase. ACS Catal 2023; 13:16249-16257. [PMID: 38125975 PMCID: PMC10729027 DOI: 10.1021/acscatal.3c04176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023]
Abstract
Imidazole glycerol phosphate synthase (IGPS) is a class-I glutamine amidotransferase (GAT) that hydrolyzes glutamine. Ammonia is produced and transferred to a second active site, where it reacts with N1-(5'-phosphoribosyl)-formimino-5-aminoimidazole-4-carboxamide ribonucleotide (PrFAR) to form precursors to purine and histidine biosynthesis. Binding of PrFAR over 25 Å away from the active site increases glutaminase efficiency by ∼4500-fold, primarily altering the glutamine turnover number. IGPS has been the focus of many studies on allosteric communication; however, atomic details for how the glutamine hydrolysis rate increases in the presence of PrFAR are lacking. We present a density functional theory study on 237-atom active site cluster models of IGPS based on crystallized structures representing the inactive and allosterically active conformations and investigate the multistep reaction leading to thioester formation and ammonia production. The proposed mechanism is supported by similar, well-studied enzyme mechanisms, and the corresponding energy profile is consistent with steady-state kinetic studies of PrFAR + IGPS. Additional active site models are constructed to examine the relationship between active site structural change and transition-state stabilization via energy decomposition schemes. The results reveal that the inactive IGPS conformation does not provide an adequately formed oxyanion hole structure and that repositioning of the oxyanion strand relative to the substrate is vital for a catalysis-competent oxyanion hole, with or without the hVal51 dihedral flip. These findings are valuable for future endeavors in modeling the IGPS allosteric mechanism by providing insight into the atomistic changes required for rate enhancement that can inform suitable reaction coordinates for subsequent investigations.
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Affiliation(s)
- Heidi Klem
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Juan V Alegre-Requena
- Dpto.de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC, Universidad de Zaragoza, Zaragoza 50009, Spain
| | - Robert S Paton
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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3
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Nakamichi Y, Kobayashi J, Toyoda K, Suda M, Hiraga K, Inui M, Watanabe M. Structural basis for the allosteric pathway of 4-amino-4-deoxychorismate synthase. Acta Crystallogr D Struct Biol 2023; 79:895-908. [PMID: 37712435 DOI: 10.1107/s2059798323006320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 07/20/2023] [Indexed: 09/16/2023] Open
Abstract
4-Amino-4-deoxychorismate synthase (ADCS), a chorismate-utilizing enzyme, is composed of two subunits: PabA and PabB. PabA is a glutamine amidotransferase that hydrolyzes glutamine into glutamate and ammonia. PabB is an aminodeoxychorismate synthase that converts chorismate to 4-amino-4-deoxychorismate (ADC) using the ammonia produced by PabA. ADCS functions under allosteric regulation between PabA and PabB. However, the allosteric mechanism remains unresolved because the structure of the PabA-PabB complex has not been determined. Here, the crystal structure and characterization of PapA from Streptomyces venezuelae (SvPapA), a bifunctional enzyme comprising the PabA and PabB domains, is reported. SvPapA forms a unique dimer in which PabA and PabB domains from different monomers complement each other and form an active structure. The chorismate-bound structure revealed that recognition of the C1 carboxyl group by Thr501 and Gly502 of the 498-PIKTG-502 motif in the PabB domain is essential for the catalytic Lys500 to reach the C2 atom, a reaction-initiation site. SvPapA demonstrated ADCS activity in the presence of Mg2+ when glutamate or NH+4 was used as the amino donor. The crystal structure indicated that the Mg2+-binding position changed depending on the binding of chorismate. In addition, significant structural changes were observed in the PabA domain depending on the presence or absence of chorismate. This study provides insights into the structural factors that are involved in the allosteric regulation of ADCS.
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Affiliation(s)
- Yusuke Nakamichi
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan
| | - Jyumpei Kobayashi
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Koichi Toyoda
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Masako Suda
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Kazumi Hiraga
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Masayuki Inui
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Masahiro Watanabe
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan
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4
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Bai Y, Jiao W, Vörster J, Parker EJ. Conformational interdomain flexibility in a bacterial α-isopropylmalate synthase is necessary for leucine biosynthesis. J Biol Chem 2022; 299:102789. [PMID: 36509144 PMCID: PMC9860122 DOI: 10.1016/j.jbc.2022.102789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
α-Isopropylmalate synthase (IPMS) catalyzes the first step in leucine (Leu) biosynthesis and is allosterically regulated by the pathway end product, Leu. IPMS is a dimeric enzyme with each chain consisting of catalytic, accessory, and regulatory domains, with the accessory and regulatory domains of each chain sitting adjacent to the catalytic domain of the other chain. The IPMS crystal structure shows significant asymmetry because of different relative domain conformations in each chain. Owing to the challenges posed by the dynamic and asymmetric structures of IPMS enzymes, the molecular details of their catalytic and allosteric mechanisms are not fully understood. In this study, we have investigated the allosteric feedback mechanism of the IPMS enzyme from the bacterium that causes meningitis, Neisseria meningitidis (NmeIPMS). By combining molecular dynamics simulations with small-angle X-ray scattering, mutagenesis, and heterodimer generation, we demonstrate that Leu-bound NmeIPMS is in a rigid conformational state stabilized by asymmetric interdomain polar interactions. Furthermore, we found removing these polar interactions by mutagenesis impaired the allosteric response without compromising Leu binding. Our results suggest that the allosteric inhibition of NmeIPMS is achieved by restricting the flexibility of the accessory and regulatory domains, demonstrating that significant conformational flexibility is required for catalysis.
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Affiliation(s)
- Yu Bai
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Wanting Jiao
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Jan Vörster
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Emily J. Parker
- Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand,Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand,For correspondence: Emily J. Parker
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5
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Wurm JP, Sung S, Kneuttinger AC, Hupfeld E, Sterner R, Wilmanns M, Sprangers R. Molecular basis for the allosteric activation mechanism of the heterodimeric imidazole glycerol phosphate synthase complex. Nat Commun 2021; 12:2748. [PMID: 33980881 PMCID: PMC8115485 DOI: 10.1038/s41467-021-22968-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 04/07/2021] [Indexed: 01/14/2023] Open
Abstract
Imidazole glycerol phosphate synthase (HisFH) is a heterodimeric bienzyme complex operating at a central branch point of metabolism. HisFH is responsible for the HisH-catalyzed hydrolysis of glutamine to glutamate and ammonia, which is then used for a cyclase reaction by HisF. The HisFH complex is allosterically regulated but the underlying mechanism is not well understood. Here, we elucidate the molecular basis of the long range, allosteric activation of HisFH. We establish that the catalytically active HisFH conformation is only formed when the substrates of both HisH and HisF are bound. We show that in this conformation an oxyanion hole in the HisH active site is established, which rationalizes the observed 4500-fold allosteric activation compared to the inactive conformation. In solution, the inactive and active conformations are in a dynamic equilibrium and the HisFH turnover rates correlate with the population of the active conformation, which is in accordance with the ensemble model of allostery. The allosteric regulation of the bienzyme complex imidazole glycerol phosphate synthase (HisFH) remains to be elucidated. Here, the authors provide structural insights into the dynamic allosteric mechanism by which ligand binding to the cyclase and glutaminase active sites of HisFH regulate enzyme activation.
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Affiliation(s)
- Jan Philip Wurm
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sihyun Sung
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Andrea Christa Kneuttinger
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Enrico Hupfeld
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany. .,University Hamburg Clinical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
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6
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Hubrich F, Müller M, Andexer JN. Chorismate- and isochorismate converting enzymes: versatile catalysts acting on an important metabolic node. Chem Commun (Camb) 2021; 57:2441-2463. [PMID: 33605953 DOI: 10.1039/d0cc08078k] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chorismate and isochorismate represent an important branching point connecting primary and secondary metabolism in bacteria, fungi, archaea and plants. Chorismate- and isochorismate-converting enzymes are potential targets for new bioactive compounds, as well as valuable biocatalysts for the in vivo and in vitro synthesis of fine chemicals. The diversity of the products of chorismate- and isochorismate-converting enzymes is reflected in the enzymatic three-dimensional structures and molecular mechanisms. Due to the high reactivity of chorismate and its derivatives, these enzymes have evolved to be accurately tailored to their respective reaction; at the same time, many of them exhibit a fascinating flexibility regarding side reactions and acceptance of alternative substrates. Here, we give an overview of the different (sub)families of chorismate- and isochorismate-converting enzymes, their molecular mechanisms, and three-dimensional structures. In addition, we highlight important results of mutagenetic approaches that generate a broader understanding of the influence of distinct active site residues for product formation and the conversion of one subfamily into another. Based on this, we discuss to what extent the recent advances in the field might influence the general mechanistic understanding of chorismate- and isochorismate-converting enzymes. Recent discoveries of new chorismate-derived products and pathways, as well as biocatalytic conversions of non-physiological substrates, highlight how this vast field is expected to continue developing in the future.
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Affiliation(s)
- Florian Hubrich
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
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7
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Prigge MJ, Wang Y, Estelle M. Mutations in the Physcomitrium patens gene encoding Aminodeoxychorismate Synthase confer auxotrophic phenotypes. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 33537559 PMCID: PMC7841435 DOI: 10.17912/micropub.biology.000364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To facilitate genetic mapping of developmental mutants of Physcomitrium patens, we produced a genetic marker that combines recessive auxotrophy with dominant positive selection. We first identified the gene affected by the pabB4 auxotrophic mutation and then replaced it with a cassette that confers antibiotic resistance. This strain may be used to produce bi-parental somatic hybrids with nearly any other strain.
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Affiliation(s)
- Michael J Prigge
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093-0116, USA
| | - Yingluo Wang
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093-0116, USA
| | - Mark Estelle
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093-0116, USA
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8
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Hertle R, Nazet J, Semmelmann F, Schlee S, Funke F, Merkl R, Sterner R. Reprogramming the Specificity of a Protein Interface by Computational and Data-Driven Design. Structure 2020; 29:292-304.e3. [PMID: 33296666 DOI: 10.1016/j.str.2020.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/21/2020] [Accepted: 11/16/2020] [Indexed: 10/22/2022]
Abstract
The formation of specific protein complexes in a cell is a non-trivial problem given the co-existence of thousands of different polypeptide chains. A particularly difficult case are two glutamine amidotransferase complexes (anthranilate synthase [AS] and aminodeoxychorismate synthase [ADCS]), which are composed of homologous pairs of synthase and glutaminase subunits. We have attempted to identify discriminating interface residues of the glutaminase subunit TrpG from AS, which are responsible for its specific interaction with the synthase subunit TrpEx and prevent binding to the closely related synthase subunit PabB from ADCS. For this purpose, TrpG-specific interface residues were grafted into the glutaminase subunit PabA from ADCS by two different approaches, namely a computational and a data-driven one. Both approaches resulted in PabA variants that bound TrpEx with higher affinity than PabB. Hence, we have accomplished a reprogramming of protein-protein interaction specificity that provides insights into the evolutionary adaptation of protein interfaces.
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Affiliation(s)
- Regina Hertle
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Julian Nazet
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Florian Semmelmann
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Sandra Schlee
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Franziska Funke
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany.
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany.
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Dörnte B, Peng C, Fang Z, Kamran A, Yulvizar C, Kües U. Selection markers for transformation of the sequenced reference monokaryon Okayama 7/#130 and homokaryon AmutBmut of Coprinopsis cinerea. Fungal Biol Biotechnol 2020; 7:15. [PMID: 33062286 PMCID: PMC7552465 DOI: 10.1186/s40694-020-00105-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Two reference strains have been sequenced from the mushroom Coprinopsis cinerea, monokaryon Okayama 7/#130 (OK130) and the self-compatible homokaryon AmutBmut. An adenine-auxotrophy in OK130 (ade8-1) and a para-aminobenzoic acid (PABA)-auxotrophy in AmutBmut (pab1-1) offer selection markers for transformations. Of these two strains, homokaryon AmutBmut had been transformed before to PABA-prototrophy and with the bacterial hygromycin resistance marker hph, respectively. RESULTS Gene ade8 encodes a bifunctional enzyme with an N-terminal glycinamide ribonucleotide synthase (GARS) and a C-terminal aminoimidazole ribonucleotide synthase (AIRS) domain required for steps 2 and 5 in the de novo biosynthesis of purines, respectively. In OK130, a missense mutation in ade8-1 rendered residue N231 for ribose recognition by the A loop of the GARS domain into D231. The new ade8 + vector pCcAde8 complements the auxotrophy of OK130 in transformations. Transformation rates with pCcAde8 in single-vector and co-transformations with ade8 +-selection were similarly high, unlike for trp1 + plasmids which exhibit suicidal feedback-effects in single-vector transformations with complementation of tryptophan synthase defects. As various other plasmids, unselected pCcAde8 helped in co-transformations of trp1 strains with a trp1 +-selection vector to overcome suicidal effects by transferred trp1 +. Co-transformation rates of pCcAde8 in OK130 under adenine selection with nuclear integration of unselected DNA were as high as 80% of clones. Co-transformation rates of expressed genes reached 26-42% for various laccase genes and up to 67% with lcc9 silencing vectors. The bacterial gene hph can also be used as another, albeit less efficient, selection marker for OK130 transformants, but with similarly high co-transformation rates. We further show that the pab1-1 defect in AmutBmut is due to a missense mutation which changed the conserved PIKGT motif for chorismate binding in the C-terminal PabB domain to PIEGT in the mutated 4-amino-4-deoxychorismate synthase. CONCLUSIONS ade8-1 and pab1-1 auxotrophic defects in C. cinerea reference strains OK130 and AmutBmut for complementation in transformation are described. pCcAde8 is a new transformation vector useful for selection in single and co-transformations of the sequenced monokaryon OK130 which was transformed for the first time. The bacterial gene hph can also be used as an additional selection marker in OK130, making in combination with ade8 + successive rounds of transformation possible.
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Affiliation(s)
- Bastian Dörnte
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, University of Goettingen, Büsgenweg 2, 37077 Goettingen, Germany
| | - Can Peng
- School of Life Sciences, Anhui University, Hefei, 230601 China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, 230601 China
| | - Zemin Fang
- School of Life Sciences, Anhui University, Hefei, 230601 China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei, 230601 China
| | - Aysha Kamran
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, University of Goettingen, Büsgenweg 2, 37077 Goettingen, Germany
- Present Address: Institute for Microbiology and Genetics, University of Goettingen, 37077 Goettingen, Germany
| | - Cut Yulvizar
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, University of Goettingen, Büsgenweg 2, 37077 Goettingen, Germany
| | - Ursula Kües
- Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, University of Goettingen, Büsgenweg 2, 37077 Goettingen, Germany
- Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
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Analysis of allosteric communication in a multienzyme complex by ancestral sequence reconstruction. Proc Natl Acad Sci U S A 2019; 117:346-354. [PMID: 31871208 DOI: 10.1073/pnas.1912132117] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tryptophan synthase (TS) is a heterotetrameric αββα complex. It is characterized by the channeling of the reaction intermediate indole and the mutual activation of the α-subunit TrpA and the β-subunit TrpB via a complex allosteric network. We have analyzed this allosteric network by means of ancestral sequence reconstruction (ASR), which is an in silico method to resurrect extinct ancestors of modern proteins. Previously, the sequences of TrpA and TrpB from the last bacterial common ancestor (LBCA) have been computed by means of ASR and characterized. LBCA-TS is similar to modern TS by forming a αββα complex with indole channeling taking place. However, LBCA-TrpA allosterically decreases the activity of LBCA-TrpB, whereas, for example, the modern ncTrpA from Neptuniibacter caesariensis allosterically increases the activity of ncTrpB. To identify amino acid residues that are responsible for this inversion of the allosteric effect, all 6 evolutionary TrpA and TrpB intermediates that stepwise link LBCA-TS with ncTS were characterized. Remarkably, the switching from TrpB inhibition to TrpB activation by TrpA occurred between 2 successive TS intermediates. Sequence comparison of these 2 intermediates and iterative rounds of site-directed mutagenesis allowed us to identify 4 of 413 residues from TrpB that are crucial for its allosteric activation by TrpA. The effect of our mutational studies was rationalized by a community analysis based on molecular dynamics simulations. Our findings demonstrate that ancestral sequence reconstruction can efficiently identify residues contributing to allosteric signal propagation in multienzyme complexes.
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Semmelmann F, Hupfeld E, Heizinger L, Merkl R, Sterner R. A Fold-Independent Interface Residue Is Crucial for Complex Formation and Allosteric Signaling in Class I Glutamine Amidotransferases. Biochemistry 2019; 58:2584-2588. [DOI: 10.1021/acs.biochem.9b00286] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Florian Semmelmann
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
| | - Enrico Hupfeld
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
| | - Leonhard Heizinger
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
| | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany
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