1
|
Stuart D, Zakhrabekova S, Jørgensen ME, Dockter C, Hansson M. A pipeline for identification of causal mutations in barley identifies Xantha-j as the chlorophyll synthase gene. PLANT PHYSIOLOGY 2024; 195:2877-2890. [PMID: 38630859 PMCID: PMC11288739 DOI: 10.1093/plphys/kiae218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/14/2024] [Accepted: 03/21/2024] [Indexed: 04/19/2024]
Abstract
Thousands of barley (Hordeum vulgare L.) mutants have been isolated over the last century, and many are stored in gene banks across various countries. In the present work, we developed a pipeline to efficiently identify causal mutations in barley. The pipeline is also efficient for mutations located in centromeric regions. Through bulked segregant analyses using whole genome sequencing of pooled F2 seedlings, we mapped 2 mutations and identified a limited number of candidate genes. We applied the pipeline on F2 mapping populations made from xan-j.59 (unknown mutation) and xan-l.82 (previously known). The Xantha-j (xan-j) gene was identified as encoding chlorophyll synthase, which catalyzes the last step in the chlorophyll biosynthetic pathway: the addition of a phytol moiety to the propionate side chain of chlorophyllide. Key amino acid residues in the active site, including the binding sites of the isoprenoid and chlorophyllide substrates, were analyzed in an AlphaFold2-generated structural model of the barley chlorophyll synthase. Three allelic mutants, xan-j.19, xan-j.59, and xan-j.64, were characterized. While xan-j.19 is a 1 base pair deletion and xan-j.59 is a nonsense mutation, xan-j.64 causes an S212F substitution in chlorophyll synthase. Our analyses of xan-j.64 and treatment of growing barley with clomazone, an inhibitor of chloroplastic isoprenoid biosynthesis, suggest that binding of the isoprenoid substrate is a prerequisite for the stable maintenance of chlorophyll synthase in the plastid. We further suggest that chlorophyll synthase is a sensor for coordinating chlorophyll and isoprenoid biosynthesis.
Collapse
Affiliation(s)
- David Stuart
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden
| | | | | | - Christoph Dockter
- Carlsberg Research Laboratory, J. C. Jacobsens Gade 4, 1799 Copenhagen V, Denmark
| | - Mats Hansson
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden
| |
Collapse
|
2
|
Caron-Godon CA, Collington E, Wolf JL, Coletta G, Glerum DM. More than Just Bread and Wine: Using Yeast to Understand Inherited Cytochrome Oxidase Deficiencies in Humans. Int J Mol Sci 2024; 25:3814. [PMID: 38612624 PMCID: PMC11011759 DOI: 10.3390/ijms25073814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Inherited defects in cytochrome c oxidase (COX) are associated with a substantial subset of diseases adversely affecting the structure and function of the mitochondrial respiratory chain. This multi-subunit enzyme consists of 14 subunits and numerous cofactors, and it requires the function of some 30 proteins to assemble. COX assembly was first shown to be the primary defect in the majority of COX deficiencies 36 years ago. Over the last three decades, most COX assembly genes have been identified in the yeast Saccharomyces cerevisiae, and studies in yeast have proven instrumental in testing the impact of mutations identified in patients with a specific COX deficiency. The advent of accessible genome-wide sequencing capabilities has led to more patient mutations being identified, with the subsequent identification of several new COX assembly factors. However, the lack of genotype-phenotype correlations and the large number of genes involved in generating a functional COX mean that functional studies must be undertaken to assign a genetic variant as being causal. In this review, we provide a brief overview of the use of yeast as a model system and briefly compare the COX assembly process in yeast and humans. We focus primarily on the studies in yeast that have allowed us to both identify new COX assembly factors and to demonstrate the pathogenicity of a subset of the mutations that have been identified in patients with inherited defects in COX. We conclude with an overview of the areas in which studies in yeast are likely to continue to contribute to progress in understanding disease arising from inherited COX deficiencies.
Collapse
Affiliation(s)
- Chenelle A. Caron-Godon
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Emma Collington
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Jessica L. Wolf
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Genna Coletta
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - D. Moira Glerum
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| |
Collapse
|
3
|
Rivett ED, Dang MA, Hegg EL. Heme o Isolation and Analysis Using Heme o Synthase Heterologously Expressed in Escherichia coli. Methods Mol Biol 2024; 2839:131-149. [PMID: 39008252 DOI: 10.1007/978-1-0716-4043-2_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Heme o is an Fe-porphyrin involved in the majority of aerobic respiration pathways found in all three domains of life. In eukaryotes and most aerobic prokaryotes, heme o functions solely as the precursor for the synthesis of heme a, a necessary cofactor for most heme-copper terminal oxidases. In some prokaryotes, such as Escherichia coli (E. coli), heme o can serve as a cofactor for heme-copper oxidases instead of heme a. Given its role as a key substrate or cofactor, purified heme o promises to be a valuable resource for the study of heme-copper oxidase assembly and activity. However, commercially available heme o is sold in limited quantities at a relatively high cost (compared to the prototypical heme b), making the use of heme o purchased from suppliers unfeasible for such studies. In this chapter, we present step-by-step methods both for heme o isolation from E. coli overexpressing heme o synthase and for HPLC analysis of cellular hemes (i.e., heme o and heme b).
Collapse
Affiliation(s)
- Elise D Rivett
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Minh Anh Dang
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
4
|
Snider AP, Gomes RS, Summers AF, Tenley SC, Abedal-Majed MA, McFee RM, Wood JR, Davis JS, Cupp AS. Identification of Lipids and Cytokines in Plasma and Follicular Fluid before and after Follicle-Stimulating Hormone Stimulation as Potential Markers for Follicular Maturation in Cattle. Animals (Basel) 2023; 13:3289. [PMID: 37894013 PMCID: PMC10603728 DOI: 10.3390/ani13203289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 10/29/2023] Open
Abstract
The process of follicle maturation leading to ovulation is a key milestone in female fertility. It is known that circulating lipids and cytokines play a role in the follicle's ability to go through follicular maturation and the ovulatory processes. However, the specific mechanisms are not well understood. We posit that dysregulation of granulosa cells influences the ovarian environment, which tries to adapt by changing released lipids and cytokines to achieve follicular maturation. Eleven non-lactating adult females underwent estrus synchronization with two injections of PGF2α 14 days apart. Daily blood samples were collected for 28 days to monitor steroid hormone production after the second injection. To understand the potential impacts of lipids and cytokines during ovulation, a low-dose FSH stimulation (FSHLow) was performed after resynchronization of cows, and daily blood samples were collected for 14 days to monitor steroid hormone production until ovariectomies. The lipidomic analysis demonstrated increased circulating diacylglycerides and triacylglycerides during the mid-luteal phase and after FSHLow treatment. Cholesteryl esters decreased in circulation but increased in follicular fluid (FF) after FSHLow. Increased circulating concentrations of TNFα and reduced CXCL9 were observed in response to FSHLow. Therefore, specific circulating lipids and cytokines may serve as markers of normal follicle maturation.
Collapse
Affiliation(s)
- Alexandria P. Snider
- United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA;
| | - Renata S. Gomes
- Department of Animal Science, University of Nebraska–Lincoln, 3940 Fair Street, Lincoln, NE 68583, USA; (R.S.G.); (J.R.W.)
| | | | - Sarah C. Tenley
- Department of Animal Science, University of Nebraska–Lincoln, 3940 Fair Street, Lincoln, NE 68583, USA; (R.S.G.); (J.R.W.)
| | - Mohamed A. Abedal-Majed
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan;
| | - Renee M. McFee
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
| | - Jennifer R. Wood
- Department of Animal Science, University of Nebraska–Lincoln, 3940 Fair Street, Lincoln, NE 68583, USA; (R.S.G.); (J.R.W.)
| | - John S. Davis
- Olson Center for Women’s Health, University of Nebraska Medical Center, 983255 Nebraska Medical Center, Omaha, NE 68198, USA;
- VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Andrea S. Cupp
- Department of Animal Science, University of Nebraska–Lincoln, 3940 Fair Street, Lincoln, NE 68583, USA; (R.S.G.); (J.R.W.)
| |
Collapse
|
5
|
Rivett ED, Addis HG, Dietz JV, Carroll-Deaton JA, Gupta S, Foreman KL, Dang MA, Fox JL, Khalimonchuk O, Hegg EL. Evidence that the catalytic mechanism of heme a synthase involves the formation of a carbocation stabilized by a conserved glutamate. Arch Biochem Biophys 2023; 744:109665. [PMID: 37348627 PMCID: PMC10529832 DOI: 10.1016/j.abb.2023.109665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/24/2023]
Abstract
In eukaryotes and many aerobic prokaryotes, the final step of aerobic respiration is catalyzed by an aa3-type cytochrome c oxidase, which requires a modified heme cofactor, heme a. The conversion of heme b, the prototypical cellular heme, to heme o and ultimately to heme a requires two modifications, the latter of which is conversion of a methyl group to an aldehyde, catalyzed by heme a synthase (HAS). The N- and C-terminal halves of HAS share homology, and each half contains a heme-binding site. Previous reports indicate that the C-terminal site is occupied by a heme b cofactor. The N-terminal site may function as the substrate (heme o) binding site, although this has not been confirmed experimentally. Here, we assess the role of conserved residues from the N- and C-terminal heme-binding sites in HAS from prokaryotic (Shewanella oneidensis) and eukaryotic (Saccharomyces cerevisiae) species - SoHAS/CtaA and ScHAS/Cox15, respectively. A glutamate within the N-terminal site is found to be critical for activity in both types of HAS, consistent with the hypothesis that a carbocation forms transiently during catalysis. In contrast, the residue occupying the analogous C-terminal position is dispensable for enzyme activity. In SoHAS, the C-terminal heme ligands are critical for stability, while in ScHAS, substitutions in either heme-binding site have little effect on global structure. In both species, in vivo accumulation of heme o requires the presence of an inactive HAS variant, highlighting a potential regulatory role for HAS in heme o biosynthesis.
Collapse
Affiliation(s)
- Elise D Rivett
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Hannah G Addis
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC, 29424, USA
| | - Jonathan V Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE, 68588, USA
| | - Jayda A Carroll-Deaton
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC, 29424, USA
| | - Shipra Gupta
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Koji L Foreman
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Minh Anh Dang
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Jennifer L Fox
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC, 29424, USA.
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE, 68588, USA; Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE, 68588, USA; Fred & Pamela Buffett Cancer Center, Omaha, NE, 68198, USA.
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
| |
Collapse
|
6
|
Pisanti S, Rimondi E, Pozza E, Melloni E, Zauli E, Bifulco M, Martinelli R, Marcuzzi A. Prenylation Defects and Oxidative Stress Trigger the Main Consequences of Neuroinflammation Linked to Mevalonate Pathway Deregulation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159061. [PMID: 35897423 PMCID: PMC9332440 DOI: 10.3390/ijerph19159061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 12/10/2022]
Abstract
The cholesterol biosynthesis represents a crucial metabolic pathway for cellular homeostasis. The end products of this pathway are sterols, such as cholesterol, which are essential components of cell membranes, precursors of steroid hormones, bile acids, and other molecules such as ubiquinone. Furthermore, some intermediates of this metabolic system perform biological activity in specific cellular compartments, such as isoprenoid molecules that can modulate different signal proteins through the prenylation process. The defects of prenylation represent one of the main causes that promote the activation of inflammation. In particular, this mechanism, in association with oxidative stress, induces a dysfunction of the mitochondrial activity. The purpose of this review is to describe the pleiotropic role of prenylation in neuroinflammation and to highlight the consequence of the defects of prenylation.
Collapse
Affiliation(s)
- Simona Pisanti
- Department of Medicine, Surgery and Dentistry ′Scuola Medica Salernitana′, University of Salerno, 84081 Baronissi, Italy; (S.P.); (R.M.)
| | - Erika Rimondi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (E.P.); (E.Z.); (A.M.)
- LTTA Centre, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: (E.R.); (E.M.)
| | - Elena Pozza
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (E.P.); (E.Z.); (A.M.)
| | - Elisabetta Melloni
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (E.P.); (E.Z.); (A.M.)
- LTTA Centre, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: (E.R.); (E.M.)
| | - Enrico Zauli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (E.P.); (E.Z.); (A.M.)
| | - Maurizio Bifulco
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, 80131 Naples, Italy;
| | - Rosanna Martinelli
- Department of Medicine, Surgery and Dentistry ′Scuola Medica Salernitana′, University of Salerno, 84081 Baronissi, Italy; (S.P.); (R.M.)
| | - Annalisa Marcuzzi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (E.P.); (E.Z.); (A.M.)
| |
Collapse
|
7
|
Diversity of Cytochrome c Oxidase Assembly Proteins in Bacteria. Microorganisms 2022; 10:microorganisms10050926. [PMID: 35630371 PMCID: PMC9145763 DOI: 10.3390/microorganisms10050926] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 12/10/2022] Open
Abstract
Cytochrome c oxidase in animals, plants and many aerobic bacteria functions as the terminal enzyme of the respiratory chain where it reduces molecular oxygen to form water in a reaction coupled to energy conservation. The three-subunit core of the enzyme is conserved, whereas several proteins identified to function in the biosynthesis of the common family A1 cytochrome c oxidase show diversity in bacteria. Using the model organisms Bacillus subtilis, Corynebacterium glutamicum, Paracoccus denitrificans, and Rhodobacter sphaeroides, the present review focuses on proteins for assembly of the heme a, heme a3, CuB, and CuA metal centers. The known biosynthesis proteins are, in most cases, discovered through the analysis of mutants. All proteins directly involved in cytochrome c oxidase assembly have likely not been identified in any organism. Limitations in the use of mutants to identify and functionally analyze biosynthesis proteins are discussed in the review. Comparative biochemistry helps to determine the role of assembly factors. This information can, for example, explain the cause of some human mitochondrion-based diseases and be used to find targets for new antimicrobial drugs. It also provides information regarding the evolution of aerobic bacteria.
Collapse
|
8
|
|