1
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Pinotsis N, Krüger A, Tomas N, Chatziefthymiou SD, Litz C, Mortensen SA, Daffé M, Marrakchi H, Antranikian G, Wilmanns M. Discovery of a non-canonical prototype long-chain monoacylglycerol lipase through a structure-based endogenous reaction intermediate complex. Nat Commun 2023; 14:7649. [PMID: 38012138 PMCID: PMC10682391 DOI: 10.1038/s41467-023-43354-4] [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] [Received: 07/13/2022] [Accepted: 11/07/2023] [Indexed: 11/29/2023] Open
Abstract
The identification and characterization of enzyme function is largely lacking behind the rapidly increasing availability of large numbers of sequences and associated high-resolution structures. This is often hampered by lack of knowledge on in vivo relevant substrates. Here, we present a case study of a high-resolution structure of an unusual orphan lipase in complex with an endogenous C18 monoacylglycerol ester reaction intermediate from the expression host, which is insoluble under aqueous conditions and thus not accessible for studies in solution. The data allowed its functional characterization as a prototypic long-chain monoacylglycerol lipase, which uses a minimal lid domain to position the substrate through a hydrophobic tunnel directly to the enzyme's active site. Knowledge about the molecular details of the substrate binding site allowed us to modulate the enzymatic activity by adjusting protein/substrate interactions, demonstrating the potential of our findings for future biotechnology applications.
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Affiliation(s)
- Nikos Pinotsis
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22607, Hamburg, Germany
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Greece
| | - Anna Krüger
- Hamburg University of Technology, Kasernenstrasse 12, 21073, Hamburg, Germany
| | - Nicolas Tomas
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier, Toulouse, France
| | | | - Claudia Litz
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22607, Hamburg, Germany
| | - Simon Arnold Mortensen
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22607, Hamburg, Germany
| | - Mamadou Daffé
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier, Toulouse, France
| | - Hedia Marrakchi
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier, Toulouse, France
| | - Garabed Antranikian
- Hamburg University of Technology, Kasernenstrasse 12, 21073, Hamburg, Germany
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22607, Hamburg, Germany.
- University Hamburg Clinical Center Hamburg-Eppendorf, Martinistrasse 52, 20251, Hamburg, Germany.
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2
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Markham L, Tolbert JD, Kull FJ, Midgett CR, Micalizio GC. An Enantiodefined Conformationally Constrained Fatty Acid Mimetic and Potent Inhibitor of ToxT. ACS Med Chem Lett 2021; 12:1493-1497. [PMID: 34531958 PMCID: PMC8436414 DOI: 10.1021/acsmedchemlett.1c00378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/20/2021] [Indexed: 11/29/2022] Open
Abstract
The chiral conformation that palmitoleic acid takes when it is bound to ToxT, the master regulator of virulence genes in the bacterial pathogen Vibrio cholerae, was used as inspiration to design a novel class of fatty acid mimetics. The best mimetic, based on a chiral hydrindane, was found to be a potent inhibitor of this target. The synthetic chemistry that enabled these studies was based on the sequential use of a stereoselective annulative cross-coupling reaction and dissolving metal reduction to establish the C13 and C9 stereocenters, respectively.
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Affiliation(s)
- Lauren
E. Markham
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - Jessica D. Tolbert
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - F. Jon Kull
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - Charles R. Midgett
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - Glenn C. Micalizio
- Department of Chemistry, Dartmouth College, Burke Laboratory, Hanover, New Hampshire 03755, United States
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3
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Jin R, Hao J, Yi Y, Sauter E, Li B. Regulation of macrophage functions by FABP-mediated inflammatory and metabolic pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158964. [PMID: 33984518 PMCID: PMC8169605 DOI: 10.1016/j.bbalip.2021.158964] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/15/2022]
Abstract
Macrophages are almost everywhere in the body, where they serve pivotal functions in maintaining tissue homeostasis, remodeling, and immunoregulation. Macrophages are traditionally thought to differentiate from bone marrow-derived hematopoietic stem cells (HSCs). Emerging studies suggest that some tissue macrophages at steady state originate from embryonic precursors in the yolk sac or fetal liver and are maintained in situ by self-renewal, but bone marrow-derived monocytes can give rise to tissue macrophages in pathogenic settings, such as inflammatory injuries and cancer. Macrophages are popularly classified as Th1 cytokine (e.g. IFNγ)-activated M1 macrophages (the classical activation) or Th2 cytokine (e.g. IL-4)-activated M2 macrophages (the alternative activation). However, given the myriad arrays of stimuli macrophages may encounter from local environment, macrophages exhibit notorious heterogeneity in their phenotypes and functions. Determining the underlying metabolic pathways engaged during macrophage activation is critical for understanding macrophage phenotypic and functional adaptivity under different disease settings. Fatty acid binding proteins (FABPs) represent a family of evolutionarily conserved proteins facilitating lipid transport, metabolism and responses inside cells. More specifically, adipose-FABP (A-FABP) and epidermal-FABP (E-FABP) are highly expressed in macrophages and play a central role in integrating metabolic and inflammatory pathways. In this review we highlight how A-FABP and E-FABP are respectively upregulated in different subsets of activated macrophages and provide a unique perspective in defining macrophage phenotypic and functional heterogeneity through FABP-regulated lipid metabolic and inflammatory pathways.
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Affiliation(s)
- Rong Jin
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, USA; Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Jiaqing Hao
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, USA
| | - Yanmei Yi
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, USA; School of Basic Medical Sciences, Guangdong Medical University, Zhanjiang, China
| | - Edward Sauter
- Division of Cancer Prevention, NIH/NCI, Bethesda, MD, USA
| | - Bing Li
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, USA.
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4
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Liu L, Jin R, Hao J, Zeng J, Yin D, Yi Y, Zhu M, Mandal A, Hua Y, Ng CK, Egilmez NK, Sauter ER, Li B. Consumption of the Fish Oil High-Fat Diet Uncouples Obesity and Mammary Tumor Growth through Induction of Reactive Oxygen Species in Protumor Macrophages. Cancer Res 2020; 80:2564-2574. [PMID: 32213543 DOI: 10.1158/0008-5472.can-19-3184] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/22/2020] [Accepted: 03/19/2020] [Indexed: 01/22/2023]
Abstract
Obesity is associated with increased risk of many types of cancer and can be induced by various high-fat diets (HFD) from different fat sources. It remains unknown whether fatty acid composition in different HFD influences obesity-associated tumor development. Here we report that consumption of either a cocoa butter or fish oil HFD induced similar obesity in mouse models. While obesity induced by the cocoa butter HFD was associated with accelerated mammary tumor growth, consumption of the fish oil HFD uncoupled obesity from increased mammary tumor growth and exhibited a decrease in protumor macrophages. Compared with fatty acid (FA) components in both HFDs, n-3 FA rich in the fish oil HFD induced significant production of reactive oxygen species (ROS) and macrophage death. Moreover, A-FABP expression in the protumor macrophages facilitated intracellular transportation of n-3 FA and oxidation of mitochondrial FA. A-FABP deficiency diminished n-3 FA-mediated ROS production and macrophage death in vitro and in vivo. Together, our results demonstrate a novel mechanism by which n-3 FA induce ROS-mediated protumor macrophage death in an A-FABP-dependent manner. SIGNIFICANCE: This study provides mechanistic insight into dietary supplementation with fish oil for breast cancer prevention and advances a new concept that not all HFDs leading to obesity are tumorigenic. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/12/2564/F1.large.jpg.
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MESH Headings
- Animals
- Carcinogenesis/immunology
- Carcinogenesis/metabolism
- Cell Line, Tumor/transplantation
- Diet, High-Fat/adverse effects
- Diet, High-Fat/methods
- Dietary Fats/adverse effects
- Fatty Acid-Binding Proteins/genetics
- Fatty Acid-Binding Proteins/metabolism
- Female
- Fish Oils/administration & dosage
- Humans
- Macrophages/cytology
- Macrophages/immunology
- Macrophages/metabolism
- Mammary Glands, Animal/cytology
- Mammary Glands, Animal/immunology
- Mammary Glands, Animal/pathology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/immunology
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/prevention & control
- Mice
- Mice, Knockout
- Mitochondria/metabolism
- Obesity/complications
- Obesity/immunology
- Obesity/metabolism
- Primary Cell Culture
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Lianliang Liu
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | - Rong Jin
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Jiaqing Hao
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | - Jun Zeng
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
- School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Di Yin
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
- School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Yanmei Yi
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
- Department of Histology and Embryology, Guangdong Medical University, Guangdong, China
| | - Mingming Zhu
- Department of Radiology, University of Louisville, Louisville, Kentucky
| | - Anita Mandal
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | - Yuan Hua
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | - Chin K Ng
- Department of Radiology, University of Louisville, Louisville, Kentucky
| | - Nejat K Egilmez
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky
| | - Edward R Sauter
- Division of Cancer Prevention, NCI, NIH, Rockville, Maryland
| | - Bing Li
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky.
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5
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Hao J, Zhang Y, Yan X, Yan F, Sun Y, Zeng J, Waigel S, Yin Y, Fraig MM, Egilmez NK, Suttles J, Kong M, Liu S, Cleary MP, Sauter E, Li B. Circulating Adipose Fatty Acid Binding Protein Is a New Link Underlying Obesity-Associated Breast/Mammary Tumor Development. Cell Metab 2018; 28:689-705.e5. [PMID: 30100196 PMCID: PMC6221972 DOI: 10.1016/j.cmet.2018.07.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 04/24/2018] [Accepted: 07/11/2018] [Indexed: 12/26/2022]
Abstract
It is clear that obesity increases the risk of many types of cancer, including breast cancer. However, the underlying molecular mechanisms by which obesity is linked to cancer risk remain to be defined. Herein, we report that circulating adipose fatty acid binding protein (A-FABP) promotes obesity-associated breast cancer development. Using clinical samples, we demonstrated that circulating A-FABP levels were significantly increased in obese patients with breast cancer in comparison with those without breast cancer. Circulating A-FABP released by adipose tissue directly targeted mammary tumor cells, enhancing tumor stemness and aggressiveness through activation of the IL-6/STAT3/ALDH1 pathway. Importantly, genetic deletion of A-FABP successfully reduced tumor ALHD1 activation and obesity-associated mammary tumor growth and development in different mouse models. Collectively, these data suggest circulating A-FABP as a new link between obesity and breast cancer risk, thereby revealing A-FABP as a potential new therapeutic target for treatment of obesity-associated cancers.
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Affiliation(s)
- Jiaqing Hao
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA
| | - Yuwen Zhang
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA
| | - Xiaofang Yan
- Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA
| | - Fei Yan
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Yanwen Sun
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA
| | - Jun Zeng
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA; School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Sabine Waigel
- Genomics Facility and Life Tech Supply Center, University of Louisville, Louisville, KY, USA
| | - Yanhui Yin
- Department of Immunology, Peking University Health Science Center, Beijing, China
| | - Mostafa M Fraig
- Department of Pathology and Laboratory Medicine, University of Louisville, Louisville, KY, USA
| | - Nejat K Egilmez
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA
| | - Jill Suttles
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA
| | - Maiying Kong
- Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA
| | - Shujun Liu
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Margot P Cleary
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Edward Sauter
- Hartford Healthcare Cancer Institute, Hartford, CT, USA
| | - Bing Li
- Department of Microbiology and Immunology, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA.
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6
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Zeng J, Zhang Y, Hao J, Sun Y, Liu S, Bernlohr DA, Sauter ER, Cleary MP, Suttles J, Li B. Stearic Acid Induces CD11c Expression in Proinflammatory Macrophages via Epidermal Fatty Acid Binding Protein. THE JOURNAL OF IMMUNOLOGY 2018; 200:3407-3419. [PMID: 29626089 DOI: 10.4049/jimmunol.1701416] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/10/2018] [Indexed: 12/21/2022]
Abstract
Obesity is associated with elevated levels of free fatty acids (FAs) and proinflammatory CD11c+ macrophages. However, whether and how free FAs contribute to CD11c+ macrophage differentiation and proinflammatory functions remain unclear. Here we report that dietary saturated FAs, but not unsaturated FAs, promoted the differentiation and function of CD11c+ macrophages. Specifically, we demonstrated that stearic acid (SA) significantly induced CD11c expression in monocytes through activation of the nuclear retinoid acid receptor. More importantly, cytosolic expression of epidermal FA binding protein (E-FABP) in monocytes/macrophages was shown to be critical to the mediation of the SA-induced effect. Depletion of E-FABP not only inhibited SA-induced CD11c upregulation in macrophages in vitro but also abrogated high-saturated-fat diet-induced skin lesions in obese mouse models in vivo. Altogether, our data demonstrate a novel mechanism by which saturated FAs promote obesity-associated inflammation through inducing E-FABP/retinoid acid receptor-mediated differentiation of CD11c+ macrophages.
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Affiliation(s)
- Jun Zeng
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202.,School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China 511436
| | - Yuwen Zhang
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202
| | - Jiaqing Hao
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202
| | - Yanwen Sun
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202
| | - Shujun Liu
- The Hormel Institute, University of Minnesota, Austin, MN 55912
| | - David A Bernlohr
- College of Biological Sciences, University of Minnesota, Minneapolis, MN 55455; and
| | | | - Margot P Cleary
- The Hormel Institute, University of Minnesota, Austin, MN 55912
| | - Jill Suttles
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202
| | - Bing Li
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202;
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7
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Zhang Y, Hao J, Zeng J, Li Q, Rao E, Sun Y, Liu L, Mandal A, Landers VD, Morris RJ, Cleary MP, Suttles J, Li B. Epidermal FABP Prevents Chemical-Induced Skin Tumorigenesis by Regulation of TPA-Induced IFN/p53/SOX2 Pathway in Keratinocytes. J Invest Dermatol 2018; 138:1925-1934. [PMID: 29559340 DOI: 10.1016/j.jid.2018.02.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/06/2018] [Accepted: 02/26/2018] [Indexed: 12/15/2022]
Abstract
Skin lipids (e.g., fatty acids) are essential for normal skin functions. Epidermal FABP (E-FABP) is the predominant FABP expressed in skin epidermis. However, the role of E-FABP in skin homeostasis and pathology remains largely unknown. Herein, we utilized the 7,12-dimethylbenz(a)anthracene and 12-O-tetradecanolyphorbol-13-acetate-induced skin tumorigenesis model to assess the role of E-FABP in chemical-induced skin tumorigenesis. Compared to their wild-type littermates, mice deficient in E-FABP, but not adipose FABP, developed more skin tumors with higher incidence. 12-O-tetradecanolyphorbol-13-acetate functioning as a tumor promoter induced E-FABP expression and initiated extensive flaring inflammation in skin. Interestingly, 12-O-tetradecanolyphorbol-13-acetate -induced production of IFN-β and IFN-λ in the skin tissue was dependent on E-FABP expression. Further protein and gene expression arrays demonstrated that E-FABP was critical in enhancing IFN-induced p53 responses and in suppressing SOX2 expression in keratinocytes. Thus, E-FABP expression in skin suppresses chemical-induced skin tumorigenesis through regulation of IFN/p53/SOX2 pathway. Collectively, our data suggest an unknown function of E-FABP in prevention of skin tumor development, and offer E-FABP as a therapeutic target for improving skin innate immunity in chemical-induced skin tumor prevention.
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Affiliation(s)
- Yuwen Zhang
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Jiaqing Hao
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Jun Zeng
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA; School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Qiang Li
- Department of Burn and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Enyu Rao
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Yanwen Sun
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Lianliang Liu
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Anita Mandal
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - V Douglas Landers
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Rebecca J Morris
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Margot P Cleary
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Jill Suttles
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Bing Li
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA.
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8
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McClelland LJ, Steele HBB, Whitby FG, Mou TC, Holley D, Alexander Ross JB, Sprang SR, Bowler BE. Cytochrome c Can Form a Well-Defined Binding Pocket for Hydrocarbons. J Am Chem Soc 2016; 138:16770-16778. [PMID: 27990813 PMCID: PMC5564421 DOI: 10.1021/jacs.6b10745] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cytochrome c can acquire peroxidase activity when it binds to cardiolipin in mitochondrial membranes. The resulting oxygenation of cardiolipin by cytochrome c provides an early signal for the onset of apoptosis. The structure of this enzyme-substrate complex is a matter of considerable debate. We present three structures at 1.7-2.0 Å resolution of a domain-swapped dimer of yeast iso-1-cytochrome c with the detergents, CYMAL-5, CYMAL-6, and ω-undecylenyl-β-d-maltopyranoside, bound in a channel that places the hydrocarbon moieties of these detergents next to the heme. The heme is poised for peroxidase activity with water bound in place of Met80, which serves as the axial heme ligand when cytochrome c functions as an electron carrier. The hydroxyl group of Tyr67 sits 3.6-4.0 Å from the nearest carbon of the detergents, positioned to act as a relay in radical abstraction during peroxidase activity. Docking studies with linoleic acid, the most common fatty acid component of cardiolipin, show that C11 of linoleic acid can sit adjacent to Tyr67 and the heme, consistent with the oxygenation pattern observed in lipidomics studies. The well-defined hydrocarbon binding pocket provides atomic resolution evidence for the extended lipid anchorage model for cytochrome c/cardiolipin binding. Dimer dissociation/association kinetics for yeast versus equine cytochrome c indicate that formation of mammalian cytochrome c dimers in vivo would require catalysis. However, the dimer structure shows that only a modest deformation of monomeric cytochrome c would suffice to form the hydrocarbon binding site occupied by these detergents.
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Affiliation(s)
- Levi J. McClelland
- Department of Chemistry & Biochemistry, University of Montana, Missoula, Montana, 59812, United States
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Harmen B. B. Steele
- Department of Chemistry & Biochemistry, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Frank G. Whitby
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, 84112, United States
| | - Tung-Chung Mou
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - David Holley
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - J. B. Alexander Ross
- Department of Chemistry & Biochemistry, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Stephen R. Sprang
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Bruce E. Bowler
- Department of Chemistry & Biochemistry, University of Montana, Missoula, Montana, 59812, United States
- Center for Biomolecular Structure & Dynamics, University of Montana, Missoula, Montana, 59812, United States
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