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Taylor J, Ayres-Galhardo PH, Brown BL. Elucidating the Role of Human ALAS2 C-terminal Mutations Resulting in Loss of Function and Disease. Biochemistry 2024; 63:1636-1646. [PMID: 38888931 PMCID: PMC11223264 DOI: 10.1021/acs.biochem.4c00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 06/20/2024]
Abstract
The conserved enzyme aminolevulinic acid synthase (ALAS) initiates heme biosynthesis in certain bacteria and eukaryotes by catalyzing the condensation of glycine and succinyl-CoA to yield aminolevulinic acid. In humans, the ALAS isoform responsible for heme production during red blood cell development is the erythroid-specific ALAS2 isoform. Owing to its essential role in erythropoiesis, changes in human ALAS2 (hALAS2) function can lead to two different blood disorders. X-linked sideroblastic anemia results from loss of ALAS2 function, while X-linked protoporphyria results from gain of ALAS2 function. Interestingly, mutations in the ALAS2 C-terminal extension can be implicated in both diseases. Here, we investigate the molecular basis for enzyme dysfunction mediated by two previously reported C-terminal loss-of-function variants, hALAS2 V562A and M567I. We show that the mutations do not result in gross structural perturbations, but the enzyme stability for V562A is decreased. Additionally, we show that enzyme stability moderately increases with the addition of the pyridoxal 5'-phosphate (PLP) cofactor for both variants. The variants display differential binding to PLP and the individual substrates compared to wild-type hALAS2. Although hALAS2 V562A is a more active enzyme in vitro, it is less efficient concerning succinyl-CoA binding. In contrast, the M567I mutation significantly alters the cooperativity of substrate binding. In combination with previously reported cell-based studies, our work reveals the molecular basis by which hALAS2 C-terminal mutations negatively affect ALA production necessary for proper heme biosynthesis.
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Affiliation(s)
- Jessica
L. Taylor
- Department
of Biochemistry, Center for Structural Biology, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
| | - Pedro H. Ayres-Galhardo
- Department
of Biochemistry, Center for Structural Biology, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
| | - Breann L. Brown
- Department
of Biochemistry, Center for Structural Biology, Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
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Thomas B, Visanica S, Poussing S, Gérard D, Perrin J. Is this really thalassemia? Am J Hematol 2023; 98:1814-1815. [PMID: 36932887 DOI: 10.1002/ajh.26913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/19/2023]
Affiliation(s)
- Benoit Thomas
- Laboratoire de biologie médicale, UNEOS Metz, Metz, France
| | | | | | - Delphine Gérard
- Hématologie biologique, CHRU Nancy, Vandoeuvre les Nancy, France
| | - Julien Perrin
- Hématologie biologique, CHRU Nancy, Vandoeuvre les Nancy, France
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Zagubnaya OA, Nartsissov YR. MOLECULAR MECHANISMS UNDERLYING THERAPEUTIC ACTION OF VITAMIN B6. PHARMACY & PHARMACOLOGY 2023. [DOI: 10.19163/2307-9266-2022-10-6-500-514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The aim of the study was to analyze the molecular mechanisms that determine the possibility of using vitamin B6 in clinical practice for the correction of various pathological conditions.Materials and methods. Information retrieval (Scopus, PubMed) and library (eLibrary) databases were used as research tools. In some cases, the ResearchGate application was used for a semantic search. The analysis and generalization of the scientific literature on the topic of research, covering the period from 1989 to the present, has been carried out in the work.Results. It has been shown that all chemical forms of vitamin B6 are able to penetrate the membranes of most cells by free diffusion, while forming phosphorylated forms inside. Pyridoxal phosphate is a biologically important metabolite that is directly involved as a cofactor in a variety of intracellular reactions. Requirements for this cofactor depend on the age, sex and condition of the patient. Pregnancy and lactation play a special role in the consumption of vitamin B6. In most cases, a balanced diet will provide an acceptable level of this vitamin. At the same time, its deficiency leads to the development of a number of pathological conditions, including neurodegenerative diseases, inflammations and diabetes. Negative manifestations from the central nervous system are also possible with an excessive consumption of B6.Conclusion. Replenishment of the vitamin B6 level in case of its identified deficiency is a necessary condition for the successful treatment of the central nervous system diseases, diabetes and correction of patients’ immune status. At the same time, it is necessary to observe a balanced intake of this cofactor in order to avoid negative effects on metabolism in case of its excess.
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Affiliation(s)
- O. A. Zagubnaya
- Institute of Cytochemistry and Molecular Pharmacology;
Biomedical Research Group, BiDiPharma GmbH
| | - Y. R. Nartsissov
- Institute of Cytochemistry and Molecular Pharmacology;
Biomedical Research Group, BiDiPharma GmbH
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4
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Cheng Z, McLaughlin DL, Little MW, Ferris C, Salavati M, Ingvartsen KL, Crowe MA, Wathes DC. Proportion of Concentrate in the Diet of Early Lactation Dairy Cows Has Contrasting Effects on Circulating Leukocyte Global Transcriptomic Profiles, Health and Fertility According to Parity. Int J Mol Sci 2022; 24:ijms24010039. [PMID: 36613482 PMCID: PMC9820068 DOI: 10.3390/ijms24010039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
The functionality of circulating leukocytes in dairy cows is suppressed after calving, with negative energy balance as a risk factor. Leukocyte transcriptomic profiles were compared separately in 44 multiparous (MP) and 18 primiparous (PP) Holstein-Friesian cows receiving diets differing in concentrate proportion to test whether immune dysfunction could be mitigated by appropriate nutrition. After calving, cows were offered either (1) low concentrate (LC); (2) medium concentrate (MC) or (3) high concentrate (HC) diets with proportions of concentrate to grass silage of 30%:70%, 50%:50% and 70%:30%, respectively. Cow phenotype data collected included circulating metabolites, milk yield and health and fertility records. RNA sequencing of circulating leukocytes at 14 days in milk was performed. The HC diet improved energy balance in both age groups. There were more differentially expressed genes in PP than MP cows (460 vs. 173, HC vs. LC comparison) with few overlaps. The MP cows on the LC diet showed upregulation of the complement and coagulation cascade and innate immune defence mechanisms against pathogens and had a trend of more cases of mastitis and poorer fertility. In contrast, the PP cows on the HC diet showed greater immune responses based on both gene expression and phenotypic data and longer interval of calving to conception. The leukocytes of MP and PP cows therefore responded differentially to the diets between age, nutrient supply and immunity affecting their health and subsequent fertility.
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Affiliation(s)
- Zhangrui Cheng
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
- Correspondence:
| | - Danielle L. McLaughlin
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
| | - Mark W. Little
- Agri-Food and Biosciences Institute, Belfast BT9 5PX, UK
| | - Conrad Ferris
- Agri-Food and Biosciences Institute, Belfast BT9 5PX, UK
| | - Mazdak Salavati
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, Easter Bush Campus, The University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Klaus L. Ingvartsen
- Department of Animal and Veterinary Science, Aarhus University, 8000 Tjele, Denmark
| | - Mark A. Crowe
- School of Veterinary Medicine, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - D. Claire Wathes
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
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Hunter GA, Ferreira GC. An Extended C-Terminus, the Possible Culprit for Differential Regulation of 5-Aminolevulinate Synthase Isoforms. Front Mol Biosci 2022; 9:920668. [PMID: 35911972 PMCID: PMC9329541 DOI: 10.3389/fmolb.2022.920668] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/30/2022] [Indexed: 12/05/2022] Open
Abstract
5-Aminolevulinate synthase (ALAS; E.C. 2.3.1.37) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that catalyzes the key regulatory step of porphyrin biosynthesis in metazoa, fungi, and α-proteobacteria. ALAS is evolutionarily related to transaminases and is therefore classified as a fold type I PLP-dependent enzyme. As an enzyme controlling the key committed and rate-determining step of a crucial biochemical pathway ALAS is ideally positioned to be subject to allosteric feedback inhibition. Extensive kinetic and mutational studies demonstrated that the overall enzyme reaction is limited by subtle conformational changes of a hairpin loop gating the active site. These findings, coupled with structural information, facilitated early prediction of allosteric regulation of activity via an extended C-terminal tail unique to eukaryotic forms of the enzyme. This prediction was subsequently supported by the discoveries that mutations in the extended C-terminus of the erythroid ALAS isoform (ALAS2) cause a metabolic disorder known as X-linked protoporphyria not by diminishing activity, but by enhancing it. Furthermore, kinetic, structural, and molecular modeling studies demonstrated that the extended C-terminal tail controls the catalytic rate by modulating conformational flexibility of the active site loop. However, the precise identity of any such molecule remains to be defined. Here we discuss the most plausible allosteric regulators of ALAS activity based on divergences in AlphaFold-predicted ALAS structures and suggest how the mystery of the mechanism whereby the extended C-terminus of mammalian ALASs allosterically controls the rate of porphyrin biosynthesis might be unraveled.
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Affiliation(s)
- Gregory A. Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- *Correspondence: Gregory A. Hunter, ; Gloria C. Ferreira,
| | - Gloria C. Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
- Department of Chemistry, College of Arts and Sciences, University of South Florida, Tampa, FL, United States
- Global and Planetary Health, College of Public Health, University of South Florida, Tampa, FL, United States
- *Correspondence: Gregory A. Hunter, ; Gloria C. Ferreira,
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Azuma K, Xiang H, Tagami T, Kasajima R, Kato Y, Karakawa S, Kikuchi S, Imaizumi A, Matsuo N, Ishii H, Tokito T, Kawahara A, Murotani K, Sasada T, Miyagi Y, Hoshino T. Clinical significance of plasma-free amino acids and tryptophan metabolites in patients with non-small cell lung cancer receiving PD-1 inhibitor: a pilot cohort study for developing a prognostic multivariate model. J Immunother Cancer 2022; 10:jitc-2021-004420. [PMID: 35569917 PMCID: PMC9109096 DOI: 10.1136/jitc-2021-004420] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2022] [Indexed: 12/18/2022] Open
Abstract
Background Amino acid metabolism is essential for tumor cell proliferation and regulation of immune cell function. However, the clinical significance of free amino acids (plasma-free amino acids (PFAAs)) and tryptophan-related metabolites in plasma has not been fully understood in patients with non-small cell lung cancer (NSCLC) who receive immune checkpoint inhibitors. Methods We conducted a single cohort observational study. Peripheral blood samples were collected from 53 patients with NSCLC before treatment with PD-1 (Programmed cell death-1) inhibitors. The plasma concentrations of 21 PFAAs, 14 metabolites, and neopterin were measured by liquid chromatography–mass spectrometry. Using Cox hazard analysis with these variables, a multivariate model was established to stratify patient overall survival (OS). Gene expression in peripheral blood mononuclear cells (PBMCs) was compared between the high-risk and low-risk patients by this multivariate model. Results On Cox proportional hazard analysis, higher concentrations of seven PFAAs (glycine, histidine, threonine, alanine, citrulline, arginine, and tryptophan) as well as lower concentrations of three metabolites (3h-kynurenine, anthranilic acid, and quinolinic acid) and neopterin in plasma were significantly correlated with better OS (p<0.05). In particular, the multivariate model, composed of a combination of serine, glycine, arginine, and quinolinic acid, could most efficiently stratify patient OS (concordance index=0.775, HR=3.23, 95% CI 2.04 to 5.26). From the transcriptome analysis in PBMCs, this multivariate model was significantly correlated with the gene signatures related to immune responses, such as CD8 T-cell activation/proliferation and proinflammatory immune responses, and 12 amino acid-related genes were differentially expressed between the high-risk and low-risk groups. Conclusions The multivariate model with PFAAs and metabolites in plasma might be useful for stratifying patients who will benefit from PD-1 inhibitors.
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Affiliation(s)
- Koichi Azuma
- Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Huihui Xiang
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Tomoyuki Tagami
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co Inc, Kawasaki, Japan
| | - Rika Kasajima
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Yumiko Kato
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co Inc, Kawasaki, Japan
| | - Sachise Karakawa
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co Inc, Kawasaki, Japan
| | - Shinya Kikuchi
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co Inc, Kawasaki, Japan
| | - Akira Imaizumi
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co Inc, Kawasaki, Japan
| | - Norikazu Matsuo
- Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Hidenobu Ishii
- Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Takaaki Tokito
- Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Akihiko Kawahara
- Department of Diagnostic Pathology, Kurume University Hospital, Kurume, Japan
| | - Kenta Murotani
- Biostatistics Center, Kurume University School of Medicine, Kurume, Japan
| | - Tetsuro Sasada
- Division of Cancer Immunotherapy, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Yohei Miyagi
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Tomoaki Hoshino
- Division of Respirology, Neurology, and Rheumatology Department of Internal Medicine, Kurume University School of Medicine, Kurume, Japan
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