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Jasuja R, Spencer D, Jayaraj A, Peng L, Krishna M, Lawney B, Patel P, Jayaram B, Thayer KM, Beveridge DL, Bhasin S. Estradiol induces allosteric coupling and partitioning of sex-hormone-binding globulin monomers among conformational states. iScience 2021; 24:102414. [PMID: 34041454 PMCID: PMC8144348 DOI: 10.1016/j.isci.2021.102414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/13/2021] [Accepted: 04/07/2021] [Indexed: 11/24/2022] Open
Abstract
Sex-hormone-binding globulin (SHBG) regulates the transport and bioavailability of estradiol. The dynamics of estradiol's binding to SHBG are incompletely understood, although it is believed that estradiol binds to each monomer of SHBG dimer with identical affinity (Kd ∼2 nM). Contrary to the prevalent view, we show that estradiol's binding to SHBG is nonlinear, and the "apparent" Kd changes with varying estradiol and SHBG concentrations. Estradiol's binding to each SHBG monomer influences residues in the ligand-binding pocket of both monomers and differentially alters the conformational and energy landscapes of both monomers. Monomers are not energetically or conformationally equivalent even in fully bound state. Estradiol's binding to SHBG involves bidirectional, inter-monomeric allostery that changes the distribution of both monomers among various energy and conformational states. Inter-monomeric allostery offers a mechanism to extend the binding range of SHBG and regulate hormone bioavailability as estradiol concentrations vary widely during life.
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Affiliation(s)
- Ravi Jasuja
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Function Promoting Therapies, Waltham, MA, USA
| | - Daniel Spencer
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Abhilash Jayaraj
- Supercomputing Facility for Bioinformatics and Computational Biology, Indian Institute of Technology, New Delhi, 110 016 India
- Departments of Chemistry, Molecular Biology, and Biochemistry and Molecular Biophysics Program, Wesleyan University, Middletown, CT, USA
| | - Liming Peng
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Meenakshi Krishna
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brian Lawney
- Center for Cancer Computational Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
- Function Promoting Therapies, Waltham, MA, USA
| | - Priyank Patel
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bhyravabhotla Jayaram
- Supercomputing Facility for Bioinformatics and Computational Biology, Indian Institute of Technology, New Delhi, 110 016 India
| | - Kelly M. Thayer
- Departments of Chemistry, Molecular Biology, and Biochemistry and Molecular Biophysics Program, Wesleyan University, Middletown, CT, USA
| | - David L. Beveridge
- Departments of Chemistry, Molecular Biology, and Biochemistry and Molecular Biophysics Program, Wesleyan University, Middletown, CT, USA
| | - Shalender Bhasin
- Research Program in Men's Health: Aging and Metabolism, Boston Claude D. Pepper Older Americans Independence Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Guadarrama-García C, Bello M, Soriano-Ursúa M. Molecular insights into how SHBG dimerization exerts changes on ligand molecular recognition. J Steroid Biochem Mol Biol 2020; 197:105502. [PMID: 31689504 DOI: 10.1016/j.jsbmb.2019.105502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/28/2019] [Accepted: 10/16/2019] [Indexed: 02/07/2023]
Abstract
Sex hormone binding globulin (SHBG) is a homodimeric glycoprotein and is the major carrier protein for sex steroids in plasma, regulating sex hormone availability in most vertebrate groups. Although it was initially thought that human dimeric SHBG bound a single ligand at the homodimer interface, studies demonstrated that dimeric SHBG binds a ligand to each subunit with similar affinity. In fact, the findings from recent experimental studies suggest that ligand binding to the SHBG dimer involves a complex allosteric mechanism involving conformational changes that limit observations of the presence of allosteric regulation. Therefore, we combined structural data with molecular dynamics simulations using Molecular Mechanics Generalized-Born Surface Area (MMGBSA) to dissect the structural and energetic basis for molecular recognition between five ligands whose affinities and binding positions on SHBG are known, i.e., 3β,17α-diol; 3β,17β-diol; DHT; norgestrel (NOG); and estradiol (E2), and monomeric and dimeric SHBG. Protein-ligand complexes, involving dimeric SHBG saturated with two ligands on each subunit, reproduce the experimental affinity tendency and allow the observation that dimerization exerts disparate effects on binding affinity, characteristic of negative cooperativity for E2, DHT, and NOG, whereas 3β-17α-diol and 3β-17β-diol lack allostery.
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Affiliation(s)
- Concepción Guadarrama-García
- Laboratorio de Modelado Molecular y Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, 11340 México City, Mexico
| | - Martiniano Bello
- Laboratorio de Modelado Molecular y Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, 11340 México City, Mexico.
| | - Marvin Soriano-Ursúa
- Departamento de Fisiología y Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, 11340 México City, Mexico
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Bobe J, Guiguen Y, Fostier A. Diversity and biological significance of sex hormone-binding globulin in fish, an evolutionary perspective. Mol Cell Endocrinol 2010; 316:66-78. [PMID: 19772892 DOI: 10.1016/j.mce.2009.09.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 09/15/2009] [Accepted: 09/16/2009] [Indexed: 11/16/2022]
Abstract
In fish, two different genes, shbga and shbgb, exist that encode for very different proteins. Shbga is the ortholog of mammalian Shbg and was found in all investigated teleosts. In contrast, Shbgb is highly divergent and appears to be a salmonid-specific protein. Here, we review existing data on fish Shbga and Shbgb that have been obtained in chondrichthyes and osteichtyes. Even though other significant expression sites exist, existing data indicate that Shbga is mainly expressed in liver and subsequently secreted into the blood as a homodimer. In contrast, Shbgb is mainly expressed in the ovary, probably secreted as a monomer, and could contribute to the regulation of local steroid action. Binding studies indicate a specialization of circulating Shbg during evolution towards the preferential binding of estradiol and testosterone in teleosts. In contrast, specific fish steroids such as 11-oxo-androgens and oocyte maturation-inducing steroids that are crucial for reproduction are poorly bound by either form of Shbg.
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Affiliation(s)
- Julien Bobe
- INRA, UR1037 SCRIBE, IFR140, Fish Reproduction Group, Ouest-Genopole, F-35000 Rennes, France.
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Marshall SH. DNA shuffling: induced molecular breeding to produce new generation long-lasting vaccines. Biotechnol Adv 2004; 20:229-38. [PMID: 14550030 DOI: 10.1016/s0734-9750(02)00015-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The paradigm for classic vaccines has been to mimic natural infection, and their success relies mostly on the induction of neutralizing antibodies followed by long-lasting immunity. The outcome of aggressive chronic infections such as HIV and HCV, the reappearance of fastidious diseases such as tuberculosis and the progression of cancer growth suggest that natural immune responses are definitely insufficient in many cases. A new paradigm is needed to design and develop a new high-efficiency generation of vaccines ideally able to surpass the capabilities of natural immune responses. In vitro evolution is a new, important laboratory method to evolve molecules with desired properties, which appears as an appealing alternative to achieve this goal. In its battle against disease, the vertebrate immune system triggers a series of well-known molecular events in order to produce protective neutralizing antibodies. This natural in vivo response shares remarkable similarities with the in vitro technique known as molecular breeding or "DNA shuffling." This method exploits the recombination between genes to dramatically accelerate the rate at which genes can be evolved under selection pressure in the laboratory, producing optimized high-efficiency mutant proteins. Since new generation vaccines are aimed to overcome natural selection and environmental pressures to fully inactivate rapidly developing pathogen variants, they could be engineered, developed and selected through the application of directed DNA shuffling procedures. This review highlights the potential of the procedure in the complex context of natural immune responses and the equilibrium and interaction existing in nature between hosts and pathogens.
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Affiliation(s)
- Sergio H Marshall
- Laboratorio de Genética e Immunologi;a Molecular, Instituto de Biología, Facultad de Ciencias Básicas y Matemáticas, Universidad Católica de Valparaíso, Casilla 4059, Valparaiso, Chile.
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Grishkovskaya I, Avvakumov GV, Hammond GL, Catalano MG, Muller YA. Steroid ligands bind human sex hormone-binding globulin in specific orientations and produce distinct changes in protein conformation. J Biol Chem 2002; 277:32086-93. [PMID: 12065592 DOI: 10.1074/jbc.m203999200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amino-terminal laminin G-like domain of human sex hormone-binding globulin (SHBG) contains a single high affinity steroid-binding site. Crystal structures of this domain in complex with several different steroid ligands have revealed that estradiol occupies the SHBG steroid-binding site in an opposite orientation when compared with 5 alpha-dihydrotestosterone or C19 androgen metabolites (5 alpha-androstan-3 beta,17 beta-diol and 5 alpha-androstan-3 beta,17 alpha-diol) or the synthetic progestin levonorgestrel. Substitution of specific residues within the SHBG steroid-binding site confirmed that Ser(42) plays a key role in determining high affinity interactions by hydrogen bonding to functional groups at C3 of the androstanediols and levonorgestrel and the hydroxyl at C17 of estradiol. Among residues participating in the hydrogen bond network with hydroxy groups at C17 of C19 steroids or C3 of estradiol, Asp(65) appears to be the most important. The different binding mode of estradiol is associated with a difference in the position/orientation of residues (Leu(131) and Lys(134)) in the loop segment (Leu(131)-His(136)) that covers the steroid-binding site as well as others (Leu(171)-Lys(173) and Trp(84)) on the surface of human SHBG and may provide a basis for ligand-dependent interactions between SHBG and other macromolecules. These new crystal structures have also enabled us to construct a simple space-filling model that can be used to predict the characteristics of novel SHBG ligands.
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Affiliation(s)
- Irina Grishkovskaya
- Forschungsgruppe Kristallographie, Max-Delbrück-Centrum für Molekulare Medizin, D-13092 Berlin, Germany
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