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Chatterjee S, Fellner M, Rankin J, Thomas MG, J S Rifayee SB, Christov CZ, Hu J, Hausinger RP. Structural, Spectroscopic, and Computational Insights from Canavanine-Bound and Two Catalytically Compromised Variants of the Ethylene-Forming Enzyme. Biochemistry 2024; 63:1038-1050. [PMID: 38577885 PMCID: PMC11025135 DOI: 10.1021/acs.biochem.4c00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/16/2024] [Accepted: 03/22/2024] [Indexed: 04/06/2024]
Abstract
The ethylene-forming enzyme (EFE) is an Fe(II), 2-oxoglutarate (2OG), and l-arginine (l-Arg)-dependent oxygenase that either forms ethylene and three CO2/bicarbonate from 2OG or couples the decarboxylation of 2OG to C5 hydroxylation of l-Arg. l-Arg binds with C5 toward the metal center, causing 2OG to change from monodentate to chelate metal interaction and OD1 to OD2 switch of D191 metal coordination. We applied anaerobic UV-visible spectroscopy, X-ray crystallography, and computational approaches to three EFE systems with high-resolution structures. The ineffective l-Arg analogue l-canavanine binds to the EFE with O5 pointing away from the metal center while promoting chelate formation by 2OG but fails to switch the D191 metal coordination from OD1 to OD2. Substituting alanine for R171 that interacts with 2OG and l-Arg inactivates the protein, prevents metal chelation by 2OG, and weakens l-Arg binding. The R171A EFE had electron density at the 2OG binding site that was identified by mass spectrometry as benzoic acid. The substitution by alanine of Y306 in the EFE, a residue 12 Å away from the catalytic metal center, generates an interior cavity that leads to multiple local and distal structural changes that reduce l-Arg binding and significantly reduce the enzyme activity. Flexibility analyses revealed correlated and anticorrelated motions in each system, with important distinctions from the wild-type enzyme. In combination, the results are congruent with the currently proposed enzyme mechanism, reinforce the importance of metal coordination by OD2 of D191, and highlight the importance of the second coordination sphere and longer range interactions in promoting EFE activity.
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Affiliation(s)
- Shramana Chatterjee
- Department
of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Matthias Fellner
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - JoelA. Rankin
- Department
of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan 48824, United States
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
| | - Midhun G. Thomas
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Jian Hu
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Robert P. Hausinger
- Department
of Microbiology, Genetics, and Immunology, Michigan State University, East Lansing, Michigan 48824, United States
- Department
of Biochemistry and Molecular Biology, Michigan
State University, East Lansing, Michigan 48824, United States
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2
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Jo J, Upadhyay T, Woods EC, Park KW, Pedowitz NJ, Jaworek-Korjakowska J, Wang S, Valdez TA, Fellner M, Bogyo M. Development of Oxadiazolone Activity-Based Probes Targeting FphE for Specific Detection of Staphylococcus aureus Infections. J Am Chem Soc 2024; 146:6880-6892. [PMID: 38411555 DOI: 10.1021/jacs.3c13974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Staphylococcus aureus (S. aureus) is a major human pathogen that is responsible for a wide range of systemic infections. Since its propensity to form biofilms in vivo poses formidable challenges for both detection and treatment, tools that can be used to specifically image S. aureus biofilms are highly valuable for clinical management. Here, we describe the development of oxadiazolone-based activity-based probes to target the S. aureus-specific serine hydrolase FphE. Because this enzyme lacks homologues in other bacteria, it is an ideal target for selective imaging of S. aureus infections. Using X-ray crystallography, direct cell labeling, and mouse models of infection, we demonstrate that oxadiazolone-based probes enable specific labeling of S. aureus bacteria through the direct covalent modification of the FphE active site serine. These results demonstrate the utility of the oxadizolone electrophile for activity-based probes and validate FphE as a target for the development of imaging contrast agents for the rapid detection of S. aureus infections.
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Affiliation(s)
- Jeyun Jo
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Tulsi Upadhyay
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Emily C Woods
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Ki Wan Park
- Department of Otolaryngology-Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Nichole J Pedowitz
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | | | - Sijie Wang
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Tulio A Valdez
- Department of Otolaryngology-Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Matthias Fellner
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
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Jo J, Upadhyay T, Woods EC, Park KW, Pedowitz NJ, Jaworek-Korjakowska J, Wang S, Valdez TA, Fellner M, Bogyo M. Development of Oxadiazolone Activity-Based Probes Targeting FphE for Specific Detection of S. aureus Infections. bioRxiv 2023:2023.12.11.571116. [PMID: 38168396 PMCID: PMC10760020 DOI: 10.1101/2023.12.11.571116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Staphylococcus aureus is a major human pathogen responsible for a wide range of systemic infections. Since its propensity to form biofilms in vivo poses formidable challenges for both detection and treatment, tools that can be used to specifically image S. aureus biofilms are highly valuable for clinical management. Here we describe the development of oxadiazolonebased activity-based probes to target the S. aureus-specific serine hydrolase FphE. Because this enzyme lacks homologs in other bacteria, it is an ideal target for selective imaging of S. aureus infections. Using X-ray crystallography, direct cell labeling and mouse models of infection we demonstrate that oxadiazolone-based probes enable specific labeling of S. aureus bacteria through the direct covalent modification of the FphE active site serine. These results demonstrate the utility of the oxadizolone electrophile for activity-based probes (ABPs) and validate FphE as a target for development of imaging contrast agents for the rapid detection of S. aureus infections.
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Affiliation(s)
- Jeyun Jo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tulsi Upadhyay
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Emily C. Woods
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ki Wan Park
- Department of Otolaryngology–Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nichole J. Pedowitz
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Sijie Wang
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tulio A. Valdez
- Department of Otolaryngology–Head & Neck Surgery Divisions, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthias Fellner
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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4
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Fellner M, Walsh A, Dela Ahator S, Aftab N, Sutherland B, Tan EW, Bakker AT, Martin NI, van der Stelt M, Lentz CS. Biochemical and Cellular Characterization of the Function of Fluorophosphonate-Binding Hydrolase H (FphH) in Staphylococcus aureus Support a Role in Bacterial Stress Response. ACS Infect Dis 2023; 9:2119-2132. [PMID: 37824340 PMCID: PMC10644348 DOI: 10.1021/acsinfecdis.3c00246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Indexed: 10/14/2023]
Abstract
The development of new treatment options for bacterial infections requires access to new targets for antibiotics and antivirulence strategies. Chemoproteomic approaches are powerful tools for profiling and identifying novel druggable target candidates, but their functions often remain uncharacterized. Previously, we used activity-based protein profiling in the opportunistic pathogen Staphylococcus aureus to identify active serine hydrolases termed fluorophosphonate-binding hydrolases (Fph). Here, we provide the first characterization of S. aureus FphH, a conserved, putative carboxylesterase (referred to as yvaK in Bacillus subtilis) at the molecular and cellular level. First, phenotypic characterization of fphH-deficient transposon mutants revealed phenotypes during growth under nutrient deprivation, biofilm formation, and intracellular survival. Biochemical and structural investigations revealed that FphH acts as an esterase and lipase based on a fold well suited to act on a small to long hydrophobic unbranched lipid group within its substrate and can be inhibited by active site-targeting oxadiazoles. Prompted by a previous observation that fphH expression was upregulated in response to fusidic acid, we found that FphH can deacetylate this ribosome-targeting antibiotic, but the lack of FphH function did not infer major changes in antibiotic susceptibility. In conclusion, our results indicate a functional role of this hydrolase in S. aureus stress responses, and hypothetical functions connecting FphH with components of the ribosome rescue system that are conserved in the same gene cluster across Bacillales are discussed. Our atomic characterization of FphH will facilitate the development of specific FphH inhibitors and probes to elucidate its physiological role and validity as a drug target.
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Affiliation(s)
- Matthias Fellner
- Biochemistry
Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Annabel Walsh
- Biochemistry
Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Stephen Dela Ahator
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Nadia Aftab
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Ben Sutherland
- Department
of Chemistry, Division of Sciences, University
of Otago, Dunedin 9054, New Zealand
| | - Eng W. Tan
- Department
of Chemistry, Division of Sciences, University
of Otago, Dunedin 9054, New Zealand
| | - Alexander T. Bakker
- Department
of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands
| | - Nathaniel I. Martin
- Biological
Chemistry Group, Institute of Biology Leiden, Leiden University, 2333
BE Leiden, The Netherlands
| | - Mario van der Stelt
- Department
of Molecular Physiology, Leiden Institute of Chemistry, Leiden University, 2333 CC Leiden, The Netherlands
| | - Christian S. Lentz
- Research
Group for Host-Microbe Interactions, Department of Medical Biology
and Centre for New Antibacterial Strategies (CANS) UiT, The Arctic University of Norway, 9037 Tromsø, Norway
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Tessadori F, Duran K, Knapp K, Fellner M, Smithson S, Beleza Meireles A, Elting MW, Waisfisz Q, O’Donnell-Luria A, Nowak C, Douglas J, Ronan A, Brunet T, Kotzaeridou U, Svihovec S, Saenz MS, Thiffault I, Del Viso F, Devine P, Rego S, Tenney J, van Haeringen A, Ruivenkamp CA, Koene S, Robertson SP, Deshpande C, Pfundt R, Verbeek N, van de Kamp JM, Weiss JM, Ruiz A, Gabau E, Banne E, Pepler A, Bottani A, Laurent S, Guipponi M, Bijlsma E, Bruel AL, Sorlin A, Willis M, Powis Z, Smol T, Vincent-Delorme C, Baralle D, Colin E, Revencu N, Calpena E, Wilkie AO, Chopra M, Cormier-Daire V, Keren B, Afenjar A, Niceta M, Terracciano A, Specchio N, Tartaglia M, Rio M, Barcia G, Rondeau S, Colson C, Bakkers J, Mace PD, Bicknell LS, van Haaften G, van Haaften G. Recurrent de novo missense variants across multiple histone H4 genes underlie a neurodevelopmental syndrome. Am J Hum Genet 2022; 109:750-758. [PMID: 35202563 PMCID: PMC9069069 DOI: 10.1016/j.ajhg.2022.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/03/2022] [Indexed: 12/12/2022] Open
Abstract
Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 Utrecht, the Netherlands.
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Fellner M. Newly discovered Staphylococcus aureus serine hydrolase probe and drug targets. ADMET DMPK 2022; 10:107-114. [PMID: 35350120 PMCID: PMC8957240 DOI: 10.5599/admet.1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 10/25/2021] [Indexed: 11/18/2022] Open
Abstract
There is an urgent need for new diagnosis and treatment options for the bacterial pathogen Staphylococcus aureus. This review will summarize data on ten recently discovered biofilm-associated serine hydrolases called fluorophosphonate-binding hydrolases (FphA-J). Based on the summarized findings, many of these proteins represent intriguing new targets for probe and drug development.
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Affiliation(s)
- Matthias Fellner
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand. ; Tel.: +64 34797897
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Schwarze M, Fieguth V, Schuch F, Sandner P, Edelmann E, Händel A, Kettler M, Hanke A, Kück M, Stein L, Stille C, Fellner M, De Angelis V, Touissant S, Specker C. [Disease-related knowledge acquisition through structured patient information in rheumatoid arthritis (StruPI-RA) : First results of the StruPI-RA study in Germany]. Z Rheumatol 2021; 80:364-372. [PMID: 32926219 PMCID: PMC8096752 DOI: 10.1007/s00393-020-00871-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND/OBJECTIVE The structured patient information for rheumatoid arthritis (StruPi-RA) program was the first standardized outpatient education program in rheumatoid arthritis (RA) in Germany. The main objective of the study was to determine the efficacy of the StruPi-RA program concerning disease-specific knowledge acquisition in patients with early stage RA or after changing the treatment regimen. METHODS A total of 61 patients were included in a control group design, 32 in the intervention group (IG) and 29 in the control group (CG). Patients of the IG attended 3 modules of 90 min in a structured patient information program (StruPI-RA) including the topics of diagnostics, treatment and living with RA. Patients in the CG only received information material from the German Rheumatism League. The primary target criterion was the disease-related acquisition of knowledge, measured with the patient knowledge questionnaire (PKQ). Data were collected before and after participation in StruPI-RA. RESULTS The improvement in knowledge in the IG attending the StruPI-RA compared to the CG was significant in time and group comparisons. No influence of disease duration or educational level was observed. The subscale treatment alone showed a significant difference in the group and time comparison. CONCLUSION Participation in the StruPI-RA program in early RA was associated with a significant increase in disease-specific knowledge compared to the control group of patients. This leads to better decision-making in terms of treatment, a more beneficial doctor-patient communication and better self-management. In the long term an improvement in treatment adherence and quality of life is expected.
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Affiliation(s)
- M Schwarze
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland.
| | - V Fieguth
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland
| | - F Schuch
- Rheumatologische Schwerpunktpraxis, Erlangen, Deutschland
| | - P Sandner
- Rheumatologische Schwerpunktpraxis, Erlangen, Deutschland
| | - E Edelmann
- Rheumazentrum Bad Aibling-Erding, Bad Aibling, Deutschland
| | - A Händel
- Rheumazentrum Bad Aibling-Erding, Bad Aibling, Deutschland
| | - M Kettler
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland
| | - A Hanke
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland
| | - M Kück
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland
| | - L Stein
- Institut für Sportmedizin, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland
| | - C Stille
- Rheumatologie-Praxis, Hannover, Deutschland
| | - M Fellner
- Rheumatologie-Praxis, Hannover, Deutschland
| | | | - S Touissant
- Rheumatologie Centrum, Leverkusen, Deutschland
| | - C Specker
- Klinik für Rheumatologie & Klinische Immunologie, Kliniken Essen-Mitte, Essen, Deutschland
- Arbeitsgemeinschaft Regionaler Kooperativer Rheumazentren in der Deutschen Gesellschaft für Rheumatologie e. V. (DGRh), Berlin, Deutschland
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Chen S, Lovell S, Lee S, Fellner M, Mace PD, Bogyo M. Identification of highly selective covalent inhibitors by phage display. Nat Biotechnol 2021; 39:490-498. [PMID: 33199876 PMCID: PMC8043995 DOI: 10.1038/s41587-020-0733-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/09/2020] [Indexed: 12/20/2022]
Abstract
Molecules that covalently bind macromolecular targets have found widespread applications as activity-based probes and as irreversibly binding drugs. However, the general reactivity of the electrophiles needed for covalent bond formation makes control of selectivity difficult. There is currently no rapid, unbiased screening method to identify new classes of covalent inhibitors from highly diverse pools of candidate molecules. Here we describe a phage display method to directly screen for ligands that bind to protein targets through covalent bond formation. This approach makes use of a reactive linker to form cyclic peptides on the phage surface while simultaneously introducing an electrophilic 'warhead' to covalently react with a nucleophile on the target. Using this approach, we identified cyclic peptides that irreversibly inhibited a cysteine protease and a serine hydrolase with nanomolar potency and exceptional specificity. This approach should enable rapid, unbiased screening to identify new classes of highly selective covalent inhibitors for diverse molecular targets.
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Affiliation(s)
- Shiyu Chen
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Scott Lovell
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sumin Lee
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Matthias Fellner
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Peter D Mace
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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Reddington CJ, Fellner M, Burgess AE, Mace PD. Molecular Regulation of the Polycomb Repressive-Deubiquitinase. Int J Mol Sci 2020; 21:ijms21217837. [PMID: 33105797 PMCID: PMC7660087 DOI: 10.3390/ijms21217837] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/16/2022] Open
Abstract
Post-translational modification of histone proteins plays a major role in histone–DNA packaging and ultimately gene expression. Attachment of ubiquitin to the C-terminal tail of histone H2A (H2AK119Ub in mammals) is particularly relevant to the repression of gene transcription, and is removed by the Polycomb Repressive-Deubiquitinase (PR-DUB) complex. Here, we outline recent advances in the understanding of PR-DUB regulation, which have come through structural studies of the Drosophila melanogaster PR-DUB, biochemical investigation of the human PR-DUB, and functional studies of proteins that associate with the PR-DUB. In humans, mutations in components of the PR-DUB frequently give rise to malignant mesothelioma, melanomas, and renal cell carcinoma, and increase disease risk from carcinogens. Diverse mechanisms may underlie disruption of the PR-DUB across this spectrum of disease. Comparing and contrasting the PR-DUB in mammals and Drosophila reiterates the importance of H2AK119Ub through evolution, provides clues as to how the PR-DUB is dysregulated in disease, and may enable new treatment approaches in cancers where the PR-DUB is disrupted.
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10
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Desguin B, Urdiain-Arraiza J, Da Costa M, Fellner M, Hu J, Hausinger RP, Desmet T, Hols P, Soumillion P. Uncovering a superfamily of nickel-dependent hydroxyacid racemases and epimerases. Sci Rep 2020; 10:18123. [PMID: 33093595 PMCID: PMC7583248 DOI: 10.1038/s41598-020-74802-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/06/2020] [Indexed: 12/13/2022] Open
Abstract
Isomerization reactions are fundamental in biology. Lactate racemase, which isomerizes L- and D-lactate, is composed of the LarA protein and a nickel-containing cofactor, the nickel-pincer nucleotide (NPN). In this study, we show that LarA is part of a superfamily containing many different enzymes. We overexpressed and purified 13 lactate racemase homologs, incorporated the NPN cofactor, and assayed the isomerization of different substrates guided by gene context analysis. We discovered two malate racemases, one phenyllactate racemase, one α-hydroxyglutarate racemase, two D-gluconate 2-epimerases, and one short-chain aliphatic α-hydroxyacid racemase among the tested enzymes. We solved the structure of a malate racemase apoprotein and used it, along with the previously described structures of lactate racemase holoprotein and D-gluconate epimerase apoprotein, to identify key residues involved in substrate binding. This study demonstrates that the NPN cofactor is used by a diverse superfamily of α-hydroxyacid racemases and epimerases, widely expanding the scope of NPN-dependent enzymes.
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Affiliation(s)
- Benoît Desguin
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, 1348, Louvain-La-Neuve, Belgium.
| | - Julian Urdiain-Arraiza
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, 1348, Louvain-La-Neuve, Belgium
| | | | - Matthias Fellner
- Biochemistry, University of Otago, PO Box 56, Dunedin, Otago, 9054, New Zealand.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Tom Desmet
- Department of Biotechnology, Ghent University, 9000, Ghent, Belgium
| | - Pascal Hols
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, 1348, Louvain-La-Neuve, Belgium
| | - Patrice Soumillion
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, 1348, Louvain-La-Neuve, Belgium
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11
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Fellner M, Lentz CS, Jamieson SA, Brewster JL, Chen L, Bogyo M, Mace PD. Structural Basis for the Inhibitor and Substrate Specificity of the Unique Fph Serine Hydrolases of Staphylococcus aureus. ACS Infect Dis 2020; 6:2771-2782. [PMID: 32865965 DOI: 10.1021/acsinfecdis.0c00503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Staphylococcus aureus is a prevalent bacterial pathogen in both community and hospital settings, and its treatment is made particularly difficult by resilience within biofilms. Within this niche, serine hydrolase enzymes play a key role in generating and maintaining the biofilm matrix. Activity-based profiling has previously identified a family of serine hydrolases, designated fluorophosphonate-binding hydrolases (Fph's), some of which contribute to the virulence of S. aureus in vivo. These 10 Fph proteins have limited annotation and have few, if any, characterized bacterial or mammalian homologues. This suggests unique hydrolase functions even within bacterial species. Here we report structures of one of the most abundant Fph family members, FphF. Our structures capture FphF alone, covalently bound to a substrate analogue and bound to small molecule inhibitors that occupy the hydrophobic substrate-binding pocket. In line with these findings, we show that FphF has promiscuous esterase activity toward hydrophobic lipid substrates. We present docking studies that characterize interactions of inhibitors and substrates within the active site environment, which can be extended to other Fph family members. Comparison of FphF to other esterases and the wider Fph protein family suggest that FphF forms a new esterase subfamily. Our data suggest that other Fph enzymes, including the virulence factor FphB, are likely to have more restricted substrate profiles than FphF. This work demonstrates a clear molecular rationale for the specificity of fluorophosphonate probes that target FphF and provides a structural template for the design of enhanced probes and inhibitors of the Fph family of serine hydrolases.
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Affiliation(s)
- Matthias Fellner
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Christian S. Lentz
- Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
- Centre for New Antibacterial Strategies (CANS) and Research Group for Host-Microbe Interactions, Department of Medical Biology, UiT − The Arctic University of Norway, Tromsø N-9037, Norway
| | - Sam A. Jamieson
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Jodi L. Brewster
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Linhai Chen
- Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Matthew Bogyo
- Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Peter D. Mace
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
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12
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Good NM, Fellner M, Demirer K, Hu J, Hausinger RP, Martinez-Gomez NC. Lanthanide-dependent alcohol dehydrogenases require an essential aspartate residue for metal coordination and enzymatic function. J Biol Chem 2020; 295:8272-8284. [PMID: 32366463 PMCID: PMC7294098 DOI: 10.1074/jbc.ra120.013227] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/30/2020] [Indexed: 01/07/2023] Open
Abstract
The lanthanide elements (Ln3+), those with atomic numbers 57-63 (excluding promethium, Pm3+), form a cofactor complex with pyrroloquinoline quinone (PQQ) in bacterial XoxF methanol dehydrogenases (MDHs) and ExaF ethanol dehydrogenases (EDHs), expanding the range of biological elements and opening novel areas of metabolism and ecology. Other MDHs, known as MxaFIs, are related in sequence and structure to these proteins, yet they instead possess a Ca2+-PQQ cofactor. An important missing piece of the Ln3+ puzzle is defining what features distinguish enzymes that use Ln3+-PQQ cofactors from those that do not. Here, using XoxF1 MDH from the model methylotrophic bacterium Methylorubrum extorquens AM1, we investigated the functional importance of a proposed lanthanide-coordinating aspartate residue. We report two crystal structures of XoxF1, one with and another without PQQ, both with La3+ bound in the active-site region and coordinated by Asp320 Using constructs to produce either recombinant XoxF1 or its D320A variant, we show that Asp320 is needed for in vivo catalytic function, in vitro activity, and La3+ coordination. XoxF1 and XoxF1 D320A, when produced in the absence of La3+, coordinated Ca2+ but exhibited little or no catalytic activity. We also generated the parallel substitution in ExaF to produce ExaF D319S and found that this variant loses the capacity for efficient ethanol oxidation with La3+ These results provide evidence that a Ln3+-coordinating aspartate is essential for the enzymatic functions of XoxF MDHs and ExaF EDHs, supporting the notion that sequences of these enzymes, and the genes that encode them, are markers for Ln3+ metabolism.
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Affiliation(s)
- Nathan M. Good
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Matthias Fellner
- Department of Biochemistry, Michigan State University, East Lansing, Michigan, USA,Department of Biochemistry, University of Otago, Dunedin, Otago, New Zealand
| | - Kemal Demirer
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA,Okemos High School, Okemos, Michigan, USA
| | - Jian Hu
- Department of Biochemistry, Michigan State University, East Lansing, Michigan, USA,Department of Chemistry, Michigan State University, East Lansing, Michigan, USA
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA,Department of Biochemistry, Michigan State University, East Lansing, Michigan, USA
| | - N. Cecilia Martinez-Gomez
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA, For correspondence: N. Cecilia Martinez-Gomez,
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13
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Affiliation(s)
- Matthias Fellner
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Robert P. Hausinger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
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14
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Fellner M, Rankin JA, Desguin B, Hu J, Hausinger RP. Analysis of the Active Site Cysteine Residue of the Sacrificial Sulfur Insertase LarE from Lactobacillus plantarum. Biochemistry 2018; 57:5513-5523. [PMID: 30157639 DOI: 10.1021/acs.biochem.8b00601] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
LarE from Lactobacillus plantarum is an ATP-dependent sulfur transferase that sacrifices its Cys176 sulfur atom to form a dehydroalanine (Dha) side chain during biosynthesis of the covalently linked nickel-pincer nucleotide (NPN) cofactor (pyridinium 3-thioamide-5-thiocarboxylic acid mononucleotide) of lactate racemase. Coenzyme A (CoA) stabilizes LarE and forms a CoA-Cys176 mixed disulfide with the protein. This study presents the crystal structure of the LarE/CoA complex, revealing protein interactions with CoA that mimic those for binding ATP. CoA weakly inhibits LarE activity, and the persulfide of CoA is capable of partially regenerating functional LarE from the Dha176 form of the protein. The physiological relevance of this cycling reaction is unclear. A new form of LarE was discovered, an NPN-LarE covalent adduct, explaining prior results in which activation of the lactate racemase apoprotein required only the isolated LarE. The crystal structure of the inactive C176A variant revealed a fold essentially identical to that of wild-type LarE. Additional active site variants of LarE were created and their activities characterized, with all LarE variants analyzed in terms of the structure. Finally, the L. plantarum LarE structure was compared to a homology model of Thermoanaerobacterium thermosaccharolyticum LarE, predicted to contain three cysteine residues at the active site, and to other proteins with a similar fold and multiple active site cysteine residues. These findings suggest that some LarE orthologs may not be sacrificial but instead may catalyze sulfur transfer by using a persulfide mechanism or from a labile site on a [4Fe-4S] cluster at this position.
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Affiliation(s)
- Matthias Fellner
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Joel A Rankin
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Benoît Desguin
- Institute of Life Sciences , Université catholique de Louvain , B-1348 Louvain-La-Neuve , Belgium
| | - Jian Hu
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States.,Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States.,Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , Michigan 48824 , United States
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15
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Hausinger RP, Desguin B, Fellner M, Rankin JA, Hu J. Nickel-pincer nucleotide cofactor. Curr Opin Chem Biol 2018; 47:18-23. [PMID: 30015232 DOI: 10.1016/j.cbpa.2018.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/15/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022]
Abstract
A novel organometallic cofactor, nickel pyridinium-3,5-dithiocarboxylic acid mononucleotide, was recently discovered in lactate racemase (LarA) of Lactobacillus plantarum. This review summarizes the substantial progress made in uncovering the function of this cofactor as a transient hydride acceptor in the LarA mechanism. The latest developments related to cofactor biosynthesis reveal insights into a pathway in which LarB serves as a nicotinic acid adenine dinucleotide hydrolase/carboxylase, LarE acts as a sacrificial sulfur transferase, and LarC functions as a nickel insertase, forming the nickel-pincer nucleotide cofactor that becomes covalently tethered to LarA in some bacteria. Bioinformatic studies reveal a widespread occurrence of larA, larB, larC, and larE orthologs in microorganisms, and additional roles for the cofactor are considered.
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Affiliation(s)
- Robert P Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
| | - Benoît Desguin
- Institute of Life Sciences, Université catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium
| | - Matthias Fellner
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Joel A Rankin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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16
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Desguin B, Fellner M, Riant O, Hu J, Hausinger RP, Hols P, Soumillion P. Biosynthesis of the nickel-pincer nucleotide cofactor of lactate racemase requires a CTP-dependent cyclometallase. J Biol Chem 2018; 293:12303-12317. [PMID: 29887527 DOI: 10.1074/jbc.ra118.003741] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/29/2018] [Indexed: 11/06/2022] Open
Abstract
Bacterial lactate racemase is a nickel-dependent enzyme that contains a cofactor, nickel pyridinium-3,5-bisthiocarboxylic acid mononucleotide, hereafter named nickel-pincer nucleotide (NPN). The LarC enzyme from the bacterium Lactobacillus plantarum participates in NPN biosynthesis by inserting nickel ion into pyridinium-3,5-bisthiocarboxylic acid mononucleotide. This reaction, known in organometallic chemistry as a cyclometalation, is characterized by the formation of new metal-carbon and metal-sulfur σ bonds. LarC is therefore the first cyclometallase identified in nature, but the molecular mechanism of LarC-catalyzed cyclometalation is unknown. Here, we show that LarC activity requires Mn2+-dependent CTP hydrolysis. The crystal structure of the C-terminal domain of LarC at 1.85 Å resolution revealed a hexameric ferredoxin-like fold and an unprecedented CTP-binding pocket. The loss-of-function of LarC variants with alanine variants of acidic residues leads us to propose a carboxylate-assisted mechanism for nickel insertion. This work also demonstrates the in vitro synthesis and purification of the NPN cofactor, opening new opportunities for the study of this intriguing cofactor and of NPN-utilizing enzymes.
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Affiliation(s)
| | | | - Olivier Riant
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium and
| | - Jian Hu
- the Departments of Biochemistry and Molecular Genetics.,Chemistry, and
| | - Robert P Hausinger
- the Departments of Biochemistry and Molecular Genetics.,Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
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17
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Rankin JA, Mauban RC, Fellner M, Desguin B, McCracken J, Hu J, Varganov SA, Hausinger RP. Lactate Racemase Nickel-Pincer Cofactor Operates by a Proton-Coupled Hydride Transfer Mechanism. Biochemistry 2018; 57:3244-3251. [PMID: 29489337 DOI: 10.1021/acs.biochem.8b00100] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lactate racemase (LarA) of Lactobacillus plantarum contains a novel organometallic cofactor with nickel coordinated to a covalently tethered pincer ligand, pyridinium-3-thioamide-5-thiocarboxylic acid mononucleotide, but its function in the enzyme mechanism has not been elucidated. This study presents direct evidence that the nickel-pincer cofactor facilitates a proton-coupled hydride transfer (PCHT) mechanism during LarA-catalyzed lactate racemization. No signal was detected by electron paramagnetic resonance spectroscopy for LarA in the absence or presence of substrate, consistent with a +2 metal oxidation state and inconsistent with a previously proposed proton-coupled electron transfer mechanism. Pyruvate, the predicted intermediate for a PCHT mechanism, was observed in quenched solutions of LarA. A normal substrate kinetic isotope effect ( kH/ kD of 3.11 ± 0.17) was established using 2-α-2H-lactate, further supporting a PCHT mechanism. UV-visible spectroscopy revealed a lactate-induced perturbation of the cofactor spectrum, notably increasing the absorbance at 340 nm, and demonstrated an interaction of the cofactor with the inhibitor sulfite. A crystal structure of LarA provided greater resolution (2.4 Å) than previously reported and revealed sulfite binding to the pyridinium C4 atom of the reduced pincer cofactor, mimicking hydride reduction during a PCHT catalytic cycle. Finally, computational modeling supports hydride transfer to the cofactor at the C4 position or to the nickel atom, but with formation of a nickel-hydride species requiring dissociation of the His200 metal ligand. In aggregate, these studies provide compelling evidence that the nickel-pincer cofactor acts by a PCHT mechanism.
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Affiliation(s)
| | - Robert C Mauban
- Department of Chemistry , University of Nevada , Reno , Nevada 89557 , United States
| | | | - Benoît Desguin
- Institute of Life Sciences , Université catholique de Louvain , B-1348 Louvain-La-Neuve , Belgium
| | | | | | - Sergey A Varganov
- Department of Chemistry , University of Nevada , Reno , Nevada 89557 , United States
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18
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Tchesnokov EP, Faponle AS, Davies CG, Quesne MG, Turner R, Fellner M, Souness RJ, Wilbanks SM, de Visser SP, Jameson GNL. An iron-oxygen intermediate formed during the catalytic cycle of cysteine dioxygenase. Chem Commun (Camb) 2018; 52:8814-7. [PMID: 27297454 PMCID: PMC5043143 DOI: 10.1039/c6cc03904a] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Combined spectroscopic, kinetic and computational studies provide first evidence of a short-lived intermediate in the catalytic cycle of cysteine dioxygenase.
Cysteine dioxygenase is a key enzyme in the breakdown of cysteine, but its mechanism remains controversial. A combination of spectroscopic and computational studies provides the first evidence of a short-lived intermediate in the catalytic cycle. The intermediate decays within 20 ms and has absorption maxima at 500 and 640 nm.
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Affiliation(s)
- E P Tchesnokov
- Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - A S Faponle
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - C G Davies
- Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - M G Quesne
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - R Turner
- Centre for Free Radical Research, University of Otago, 2 Riccarton Ave, PO Box 4345, Christchurch, New Zealand
| | - M Fellner
- Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - R J Souness
- Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology University of Otago, PO Box 56, Dunedin 9054, New Zealand.
| | - S M Wilbanks
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - S P de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - G N L Jameson
- Department of Chemistry & MacDiarmid Institute for Advanced Materials and Nanotechnology University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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19
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Martinez S, Fellner M, Herr CQ, Ritchie A, Hu J, Hausinger RP. Structures and Mechanisms of the Non-Heme Fe(II)- and 2-Oxoglutarate-Dependent Ethylene-Forming Enzyme: Substrate Binding Creates a Twist. J Am Chem Soc 2017; 139:11980-11988. [PMID: 28780854 PMCID: PMC5599930 DOI: 10.1021/jacs.7b06186] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The ethylene-forming enzyme (EFE) from Pseudomonas syringae pv. phaseolicola PK2 is a member of the mononuclear nonheme Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenase superfamily. EFE converts 2OG into ethylene plus three CO2 molecules while also catalyzing the C5 hydroxylation of l-arginine (l-Arg) driven by the oxidative decarboxylation of 2OG to form succinate and CO2. Here we report 11 X-ray crystal structures of EFE that provide insight into the mechanisms of these two reactions. Binding of 2OG in the absence of l-Arg resulted in predominantly monodentate metal coordination, distinct from the typical bidentate metal-binding species observed in other family members. Subsequent addition of l-Arg resulted in compression of the active site, a conformational change of the carboxylate side chain metal ligand to allow for hydrogen bonding with the substrate, and creation of a twisted peptide bond involving this carboxylate and the following tyrosine residue. A reconfiguration of 2OG achieves bidentate metal coordination. The dioxygen binding site is located on the metal face opposite to that facing l-Arg, thus requiring reorientation of the generated ferryl species to catalyze l-Arg hydroxylation. Notably, a phenylalanyl side chain pointing toward the metal may hinder such a ferryl flip and promote ethylene formation. Extensive site-directed mutagenesis studies supported the importance of this phenylalanine and confirmed the essential residues used for substrate binding and catalysis. The structural and functional characterization described here suggests that conversion of 2OG to ethylene, atypical among Fe(II)/2OG oxygenases, is facilitated by the binding of l-Arg which leads to an altered positioning of the carboxylate metal ligand, a resulting twisted peptide bond, and the off-line geometry for dioxygen coordination.
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Affiliation(s)
- Salette Martinez
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
| | - Matthias Fellner
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Caitlyn Q Herr
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Anastasia Ritchie
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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20
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Zhang T, Liu J, Fellner M, Zhang C, Sui D, Hu J. Crystal structures of a ZIP zinc transporter reveal a binuclear metal center in the transport pathway. Sci Adv 2017; 3:e1700344. [PMID: 28875161 PMCID: PMC5573306 DOI: 10.1126/sciadv.1700344] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/26/2017] [Indexed: 05/20/2023]
Abstract
Zrt/Irt-like proteins (ZIPs) play fundamental roles in metal metabolism/homeostasis and are broadly involved in numerous physiological and pathological processes. The lack of high-resolution structure of the ZIPs hinders understanding of the metal transport mechanism. We report two crystal structures of a prokaryotic ZIP in lipidic cubic phase with bound metal substrates (Cd2+ at 2.7 Å and Zn2+ at 2.4 Å). The structures revealed a novel 3+2+3TM architecture and an inward-open conformation occluded at the extracellular side. Two metal ions were trapped halfway through the membrane, unexpectedly forming a binuclear metal center. The Zn2+-substituted structure suggested asymmetric functions of the two metal-binding sites and also revealed a route for zinc release. Mapping of disease-causing mutations, structure-guided mutagenesis, and cell-based zinc transport assay demonstrated the crucial role of the binuclear metal center for human ZIP4. A metal transport mechanism for the ZIP from Bordetella bronchiseptica was proposed, which is likely applicable to other ZIPs.
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Affiliation(s)
- Tuo Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Matthias Fellner
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Chi Zhang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Dexin Sui
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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21
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Fellner M, Siakkou E, Faponle AS, Tchesnokov EP, de Visser SP, Wilbanks SM, Jameson GNL. Influence of cysteine 164 on active site structure in rat cysteine dioxygenase. J Biol Inorg Chem 2016; 21:501-10. [PMID: 27193596 DOI: 10.1007/s00775-016-1360-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/07/2016] [Indexed: 11/29/2022]
Abstract
Cysteine dioxygenase is a non-heme mononuclear iron enzyme with unique structural features, namely an intramolecular thioether cross-link between cysteine 93 and tyrosine 157, and a disulfide bond between substrate L-cysteine and cysteine 164 in the entrance channel to the active site. We investigated how these posttranslational modifications affect catalysis through a kinetic, crystallographic and computational study. The enzyme kinetics of a C164S variant are identical to WT, indicating that disulfide formation at C164 does not significantly impair access to the active site at physiological pH. However, at high pH, the cysteine-tyrosine cross-link formation is enhanced in C164S. This supports the view that disulfide formation at position 164 can limit access to the active site. The C164S variant yielded crystal structures of unusual clarity in both resting state and with cysteine bound. Both show that the iron in the cysteine-bound complex is a mixture of penta- and hexa-coordinate with a water molecule taking up the final site (60 % occupancy), which is where dioxygen is believed to coordinate during turnover. The serine also displays stronger hydrogen bond interactions to a water bound to the amine of the substrate cysteine. However, the interactions between cysteine and iron appear unchanged. DFT calculations support this and show that WT and C164S have similar binding energies for the water molecule in the final site. This variant therefore provides evidence that WT also exists in an equilibrium between penta- and hexa-coordinate forms and the presence of the sixth ligand does not strongly affect dioxygen binding.
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Affiliation(s)
- Matthias Fellner
- Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Eleni Siakkou
- Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Abayomi S Faponle
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Egor P Tchesnokov
- Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Sam P de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Sigurd M Wilbanks
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Guy N L Jameson
- Department of Chemistry, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
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22
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Fellner M, Aloi S, Tchesnokov EP, Wilbanks SM, Jameson GNL. Substrate and pH-Dependent Kinetic Profile of 3-Mercaptopropionate Dioxygenase from Pseudomonas aeruginosa. Biochemistry 2016; 55:1362-71. [DOI: 10.1021/acs.biochem.5b01203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthias Fellner
- Department of Chemistry and ‡Department of
Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Sekotilani Aloi
- Department of Chemistry and ‡Department of
Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Egor P. Tchesnokov
- Department of Chemistry and ‡Department of
Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Sigurd M. Wilbanks
- Department of Chemistry and ‡Department of
Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Guy N. L. Jameson
- Department of Chemistry and ‡Department of
Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
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Tchesnokov EP, Fellner M, Siakkou E, Kleffmann T, Martin LW, Aloi S, Lamont IL, Wilbanks SM, Jameson GNL. The cysteine dioxygenase homologue from Pseudomonas aeruginosa is a 3-mercaptopropionate dioxygenase. J Biol Chem 2015; 290:24424-37. [PMID: 26272617 PMCID: PMC4591825 DOI: 10.1074/jbc.m114.635672] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 08/02/2015] [Indexed: 02/02/2023] Open
Abstract
Thiol dioxygenation is the initial oxidation step that commits a thiol to important catabolic or biosynthetic pathways. The reaction is catalyzed by a family of specific non-heme mononuclear iron proteins each of which is reported to react efficiently with only one substrate. This family of enzymes includes cysteine dioxygenase, cysteamine dioxygenase, mercaptosuccinate dioxygenase, and 3-mercaptopropionate dioxygenase. Using sequence alignment to infer cysteine dioxygenase activity, a cysteine dioxygenase homologue from Pseudomonas aeruginosa (p3MDO) has been identified. Mass spectrometry of P. aeruginosa under standard growth conditions showed that p3MDO is expressed in low levels, suggesting that this metabolic pathway is available to the organism. Purified recombinant p3MDO is able to oxidize both cysteine and 3-mercaptopropionic acid in vitro, with a marked preference for 3-mercaptopropionic acid. We therefore describe this enzyme as a 3-mercaptopropionate dioxygenase. Mössbauer spectroscopy suggests that substrate binding to the ferrous iron is through the thiol but indicates that each substrate could adopt different coordination geometries. Crystallographic comparison with mammalian cysteine dioxygenase shows that the overall active site geometry is conserved but suggests that the different substrate specificity can be related to replacement of an arginine by a glutamine in the active site.
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Affiliation(s)
| | | | | | - Torsten Kleffmann
- Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Lois W Martin
- Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | | | - Iain L Lamont
- Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Sigurd M Wilbanks
- Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
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Davies CG, Fellner M, Tchesnokov EP, Wilbanks SM, Jameson GNL. The Cys-Tyr cross-link of cysteine dioxygenase changes the optimal pH of the reaction without a structural change. Biochemistry 2014; 53:7961-8. [PMID: 25390690 DOI: 10.1021/bi501277a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cysteine dioxygenase (CDO) is a non-heme monoiron enzyme with an unusual posttranslational modification in the proximity of the ferrous iron active site. This modification, a cysteine to tyrosine thioether bond, cross-links two β-strands of the β-barrel. We have investigated its role in catalysis through a combined crystallographic and kinetic approach. The C93G variant lacks the cross-link and shows little change in structure from that of the wild type, suggesting that the cross-link does not stabilize an otherwise unfavorable conformation. A pH-dependent kinetic study shows that both cross-linked and un-cross-linked CDO are active but the optimal pH decreases with the presence of the cross-link. This result reflects the effect of the thioether bond on the pKa of Y157 and this residue's role in catalysis. At higher pH values, kcat is also higher for the cross-linked form, extending the pH range of activity. We therefore propose that the cross-link also increases activity by controlling deleterious interactions involving the thiol/ate of C93.
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Affiliation(s)
- Casey G Davies
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology and ‡Department of Biochemistry, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand
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Fellner M, Doughty LM, Jameson GN, Wilbanks SM. A chromogenic assay of substrate depletion by thiol dioxygenases. Anal Biochem 2014; 459:56-60. [DOI: 10.1016/j.ab.2014.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 12/01/2022]
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Kurz T, Fellner M, Becker T, Delgado A. Observation and Control of the Beer Fermentation Using Cognitive Methods. Journal of the Institute of Brewing 2013. [DOI: 10.1002/j.2050-0416.1953.tb06933.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kurz T, Fellner M, Becker T, Delgado A. Observation and Control of the Beer Fermentation Using Cognitive Methods. Journal of the Institute of Brewing 2012. [DOI: 10.1002/j.2050-0416.2001.tb00096.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dieber-Rotheneder M, Beganovic S, Fellner M, Lang U, Desoye G, Cervar-Zivkovic M. Endothelin/endothelin receptor system is upregulated in preeclampsia with or without fetal growth restriction in contrast to gestational diabetes. Geburtshilfe Frauenheilkd 2011. [DOI: 10.1055/s-0031-1286419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Fellner M, Riss P, Loktionova NS, Zhernosekov KP, Thews O, Geraldes CFGC, Kovacs Z, Lukes I, Rösch F. Comparison of different phosphorus-containing ligands complexing 68Ga for PET-imaging of bone metabolism. RADIOCHIM ACTA 2010. [DOI: 10.1524/ract.2011.1791] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Abstract
99mTc-phosphonate structures are well established tracers for bone tumour imaging. Our objective was to investigate different 68Ga-labelled phosphonate ligands concerning labelling kinetics, binding to hydroxyapatite and bone imaging using μ-PET. Seven macrocyclic phosphorus-containing ligands and EDTMP were labelled in nanomolar scale with n.c.a. 68Ga in Na-HEPES buffer at pH∼4. Except for DOTP, all ligands were labelled with >92% yield. Binding of the 68Ga-ligand complexes on hydroxyapatite was analysed to evaluate the effect of the number of the phosphorus acid groups on adsorption parameters. Adsorption of 68Ga-EDTMP and 68Ga-DOTP was >83%. For the 68Ga-NOTA-phosphonates an increasing binding with increasing number of phosphonate groups was observed but was still lower than 68Ga-DOTP and 68Ga-EDTMP. μ-PET studies in vivo were performed with 68Ga-EDTMP and 68Ga-DOTP with Wistar rats. While 68Ga-EDTMP-PET showed uptake on bone structures, an excess amount of the ligand (>1.5 mg EDTMP/kg body weight) had to be used, otherwise the 68Ga3+ is released from the complex and forms gallium hydroxide or it is transchelated to 68Ga-transferrin. As a result, the main focus of further phosphonate structures has to be on complex formation in high radiochemical yields with macrocyclic ligands with phosphonate groups that are not required for complexing 68Ga.
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Affiliation(s)
- M. Fellner
- Johannes Gutenberg University of Mainz, Institute of Nuclear Chemistry, Mainz
| | - P. Riss
- Universität Mainz, Institute of Nuclear Chemistry, Mainz
| | | | - K. P. Zhernosekov
- Johannes Gutenberg-Universität of Mainz, Institute of Nuclear Chemistry, Mainz
| | - O. Thews
- Johannes Gutenberg University of Mainz, Institute of Pathophysiology, Mainz
| | | | - Z. Kovacs
- University of Texas Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX 75235-9085, U.S.A
| | - I. Lukes
- Charles University, Department of Inorganic Chemistry, Prague, Tschechische Republik
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Fellner M, Delgado A, Becker T. Functional nodes in dynamic neural networks for bioprocess modelling. Bioprocess Biosyst Eng 2003; 25:263-70. [PMID: 14505169 DOI: 10.1007/s00449-002-0297-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2002] [Accepted: 07/30/2002] [Indexed: 10/24/2022]
Abstract
This contribution presents a novel method for the direct integration of a-priori knowledge in a neural network and its application for the online determination of a secondary metabolite during industrial yeast fermentation. Hereby, existing system knowledge is integrated in an artificial neural network (ANN) by means of 'functional nodes'. A generalized backpropagation algorithm is presented. For illustration, a set of ordinary differential equations describing the diacetyl formation and degradation during the cultivation is incorporated in a functional node and integrated in a dynamic feedforward neural network in a hybrid manner. The results show that a hybrid modelling approach exploiting available a-priori knowledge and experimental data can considerably outperform a pure data-based modelling approach with respect to robustness, generalization and necessary amount of training data. The number of training sets were decreased by 50%, obtaining the same accuracy as in a conventional approach. All incorrect decisions, according to defined cost criteria obtained with the conventional ANN, were avoided.
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Affiliation(s)
- M Fellner
- Lehrstuhl für Fluidmechanik und Prozessautomation, Technische Universität München, Aussenstelle Freising-Weihenstephan, Weihenstephaner Steig 23, 85350 Freising, Germany.
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Fellner M, Zhang R, Pharis RP, Sawhney VK. Reduced de-etiolation of hypocotyl growth in a tomato mutant is associated with hypersensitivity to, and high endogenous levels of, abscisic acid. J Exp Bot 2001; 52:725-738. [PMID: 11413209 DOI: 10.1093/jexbot/52.357.725] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A recessive single gene mutant, 7B-1, in tomato was originally selected for its photoperiod-dependent male sterility. The 7B-1 mutant also has some pleiotropic effects including reduced light-induced inhibition, i.e. de-etiolation, of the hypocotyl in long days (LD), increased seed size and weight, and reduced transpiration rate. These traits led us to investigate the sensitivity of 7B-1 to exogenous hormones and the interaction of these responses with daylength. In LD, but not in short days (SD), 7B-1 was more sensitive than wild-type (WT) to exogenous abscisic acid (ABA) for inhibition of seed germination, root elongation and transpiration rate. 7B-1 mutant also exhibited reduced responses to exogenous gibberellin (GA(3)) for hypocotyl elongation, and to inhibitors of GA biosynthesis for seed germination and root and hypocotyl elongation. 7B-1 hypocotyls contained a higher level of endogenous ABA than WT in both photoperiods, although ABA levels were higher in LD than in SD. In contrast, growth-active GAs, i.e. GA(1), GA(3) and GA(4), and IAA were low in the mutant hypocotyls. The 7B-1 mutant appears to be an ABA-overproducer, and the photoperiod-regulated ABA levels may be responsible for the hypersensitivity of the mutant to exogenous ABA.
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Affiliation(s)
- M Fellner
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
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Ephritikhine G, Fellner M, Vannini C, Lapous D, Barbier-Brygoo H. The sax1 dwarf mutant of Arabidopsis thaliana shows altered sensitivity of growth responses to abscisic acid, auxin, gibberellins and ethylene and is partially rescued by exogenous brassinosteroid. Plant J 1999; 18:303-14. [PMID: 10377995 DOI: 10.1046/j.1365-313x.1999.00454.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Genetic approaches using Arabidopsis thaliana aimed at the identification of mutations affecting events involved in auxin signalling have usually led to the isolation of auxin-resistant mutants. From a selection screen specifically developed to isolate auxin-hypersensitive mutants, one mutant line was selected for its increased sensitivity to auxin (x 2 to 3) for the root elongation response. The genetic analysis of sax1 (hypersensitive to abscisic acid and auxin) indicated that the mutant phenotype segregates as a single recessive Mendelian locus, mapping to the lower arm of chromosome 1. Sax1 seedlings grown in vitro showed a short curled primary root and small, round, dark-green cotyledons. In the greenhouse, adult sax1 plants were characterized by a dwarf phenotype, delayed development and reduced fertility. Further physiological characterization of sax1 seedlings revealed that the most striking trait was a large increase (x 40) in ABA-sensitivity of root elongation and, to a lesser extent, of ABA-induced stomatal closure; in other respects, hypocotyl elongation was resistant to gibberellins and ethylene. These alterations in hormone sensitivity in sax1 plants co-segregated with the dwarf phenotype suggesting that processes involved in cell elongation are modified. Treatment of mutant seedlings with an exogenous brassinosteroid partially rescued a wild-type size, suggesting that brassinosteroid biosynthesis might be affected in sax1 plants. Wild-type sensitivities to ABA, auxin and gibberellins were also restored in sax1 plants by exogenous application of brassinosteroid, illustrating the pivotal importance of the BR-related SAX1 gene.
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Affiliation(s)
- G Ephritikhine
- Institut des Sciences Végétales, Centre National de la Recherche Scientifique, Gif sur Yvette, France.
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Beckerman A, Fellner M, Fisher L. Penicillin-induced skin eruption. Int J Dermatol 1984; 23:149. [PMID: 6230330 DOI: 10.1111/j.1365-4362.1984.tb05692.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Cleland CC, Hereford SM, Fellner M, Lawrence W. Parental behaviors in profoundly retarded subjects. Percept Mot Skills 1973; 36:215-8. [PMID: 4686713 DOI: 10.2466/pms.1973.36.1.215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The behavior of 13 male and 16 female profoundly retarded adults (18 to 30 yr. old) in response to the visual stimulus of a human infant was observed. Little support was obtained for the ethologically based hypothesis that the infant as a sign-stimulus would release parental (i.e., approach) behavior. However, significantly more active-approach behavior was observed in female than male Ss.
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Hereford SM, Cleland CC, Fellner M. Territoriality and scent-marking: a study of profoundly retarded enuretics and encopretics. Am J Ment Defic 1973; 77:426-30. [PMID: 4706403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Fellner M. V. Bemerkungen über psoriasiforme Salvarsan – (Syntharsan) Exantheme und Beeinflussung der morphologischen Gestaltung der Psoriasis bei einem Luetiker durch spezifische Therapie. Dermatology 1931. [DOI: 10.1159/000257651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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