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Cortez-Romero CR, Lyu J, Pillai AS, Langanowsky A, Thornton JW. Imperfect symmetry facilitated the evolution of specificity and high-order stoichiometry in vertebrate hemoglobin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.24.604985. [PMID: 39091803 PMCID: PMC11291130 DOI: 10.1101/2024.07.24.604985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Many proteins form paralogous multimers - molecular complexes in which evolutionarily related proteins are arranged into specific quaternary structures. Little is known about the mechanisms by which they acquired their stoichiometry (the number of total subunits in the complex) and heterospecificity (the preference of subunits for their paralogs rather than other copies of the same protein). Here we use ancestral protein reconstruction and biochemical experiments to study historical increases in stoichiometry and specificity during the evolution of vertebrate hemoglobin (Hb), a α2β2 heterotetramer that evolved from a homodimeric ancestor after a gene duplication. We show that the mechanisms for this evolutionary transition was simple. One hydrophobic substitution in subunit β after the gene duplication was sufficient to cause the ancestral dimer to homotetramerize with high affinity across a new interface. During this same interval, a single-residue deletion in subunit α at the older interface conferred specificity for the heterotetrameric form and the trans-orientation of subunits within it. These sudden transitions in stoichiometry and specificity were possible because the interfaces in Hb are isologous - involving the same surface patch on interacting subunits, rotated 180° relative to each other - but the symmetry is slightly imperfect. This architecture amplifies the impacts of individual mutations on stoichiometry and specificity, especially in higher-order complexes, and allows single substitutions to differentially affect heteromeric vs homomeric interactions. Many multimers are isologous, and symmetry in proteins is always imperfect; our findings therefore suggest that elaborate and specific molecular complexes may often evolve via simple genetic and physical mechanisms.
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Affiliation(s)
| | - Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, TX, 77843
| | - Arvind S Pillai
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, 60637
- Institute of Protein Design, University of Washington, Seattle, WA, 98195
| | - Arthur Langanowsky
- Department of Chemistry, Texas A&M University, College Station, TX, 77843
| | - Joseph W Thornton
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, 60637
- Department of Chemistry, Texas A&M University, College Station, TX, 77843
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2
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Tian T, Wu X, Wu P, Lu X, Wang Q, Lin Y, Liu C, Zhou J, Yu Y, Lu H. High-level expression of leghemoglobin in Kluyveromyces marxianus by remodeling the heme metabolism pathway. Front Bioeng Biotechnol 2024; 11:1329016. [PMID: 38264583 PMCID: PMC10804453 DOI: 10.3389/fbioe.2023.1329016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/19/2023] [Indexed: 01/25/2024] Open
Abstract
Soy leghemoglobin, when bound to heme, imparts a meat-like color and flavor and can serve as a substitute for animal-derived proteins. Enhancing cellular heme synthesis improves the recombinant expression of leghemoglobin in yeast. To achieve high-level expression of leghemoglobin A (LBA) in Kluyveromyces marxianus, a food-safe yeast, large-scale heme synthesis modules were transferred into K. marxianus using yeast artificial chromosomes (KmYACs). These modules contained up to 8 native and heterologous genes to promote the supply of heme precursors and downstream synthesis. Next, eight genes inhibiting heme or LBA synthesis were individually or combinatorially deleted, with the lsc1Δssn3Δ mutant yielding the best results. Subsequently, heme synthesis modules were combined with the lsc1Δssn3Δ mutant. In the resulting strains, the module genes were all actively expressed. Among these module genes, heterologous S. cerevisiae genes in the downstream heme synthesis pathway significantly enhanced the expression of their counterparts in K. marxianus, resulting in high heme content and LBA yield. After optimizing the medium recipe by adjusting the concentrations of glucose, glycine, and FeSO4·7H2O, a heme content of 66.32 mg/L and an intracellular LBA titer of 7.27 g/L were achieved in the engineered strain in a 5 L fermentor. This represents the highest intracellular expression of leghemoglobin in microorganisms to date. The leghemoglobin produced by K. marxianus can be utilized as a safe ingredient for plant-based protein products.
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Affiliation(s)
- Tian Tian
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Xinwei Wu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Pingping Wu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Xinyi Lu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Qi Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Yifan Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Canjie Liu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Jungang Zhou
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Yao Yu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Hong Lu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
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Natarajan C, Signore AV, Bautista NM, Hoffmann FG, Tame JRH, Fago A, Storz JF. Evolution and molecular basis of a novel allosteric property of crocodilian hemoglobin. Curr Biol 2023; 33:98-108.e4. [PMID: 36549299 PMCID: PMC9839640 DOI: 10.1016/j.cub.2022.11.049] [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: 09/07/2022] [Revised: 10/25/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022]
Abstract
The extraordinary breath-hold diving capacity of crocodilians has been ascribed to a unique mode of allosterically regulating hemoglobin (Hb)-oxygenation in circulating red blood cells. We investigated the origin and mechanistic basis of this novel biochemical phenomenon by performing directed mutagenesis experiments on resurrected ancestral Hbs. Comparisons of Hb function between the common ancestor of archosaurs (the group that includes crocodilians and birds) and the last common ancestor of modern crocodilians revealed that regulation of Hb-O2 affinity via allosteric binding of bicarbonate ions represents a croc-specific innovation that evolved in combination with the loss of allosteric regulation by ATP binding. Mutagenesis experiments revealed that evolution of the novel allosteric function in crocodilians and the concomitant loss of ancestral function were not mechanistically coupled and were caused by different sets of substitutions. The gain of bicarbonate sensitivity in crocodilian Hb involved the direct effect of few amino acid substitutions at key sites in combination with indirect effects of numerous other substitutions at structurally disparate sites. Such indirect interaction effects suggest that evolution of the novel protein function was conditional on neutral mutations that produced no adaptive benefit when they first arose but that contributed to a permissive background for subsequent function-altering mutations at other sites. Due to the context dependence of causative substitutions, the unique allosteric properties of crocodilian Hb cannot be easily transplanted into divergent homologs of other species.
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Affiliation(s)
| | - Anthony V Signore
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Naim M Bautista
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA
| | - Jeremy R H Tame
- Drug Design Laboratory, Yokohama City University, Yokohama 230-0045, Japan
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, DK-8000 Aarhus, Denmark
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA.
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Charbe NB, Castillo F, Tambuwala MM, Prasher P, Chellappan DK, Carreño A, Satija S, Singh SK, Gulati M, Dua K, González-Aramundiz JV, Zacconi FC. A new era in oxygen therapeutics? From perfluorocarbon systems to haemoglobin-based oxygen carriers. Blood Rev 2022; 54:100927. [PMID: 35094845 DOI: 10.1016/j.blre.2022.100927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 12/14/2021] [Accepted: 01/12/2022] [Indexed: 02/09/2023]
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5
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Kettisen K, Bülow L. Introducing Negatively Charged Residues on the Surface of Fetal Hemoglobin Improves Yields in Escherichia coli. Front Bioeng Biotechnol 2021; 9:721794. [PMID: 34552916 PMCID: PMC8450383 DOI: 10.3389/fbioe.2021.721794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/20/2021] [Indexed: 11/14/2022] Open
Abstract
Fetal hemoglobin (HbF) has been developed into an important alternative protein for oxygen therapeutics. Such applications require extensive amounts of proteins, which only can be achieved via recombinant means. However, the expression of vertebrate hemoglobins in heterologous hosts is far from trivial. There are several issues that need to be dealt with. These include, among others, the solubility of the globin chains, equimolar expression of the globin chains, and access to high levels of free heme. In this study, we examined the impact of introducing negative charges on the surface of HbF. Three different HbF mutants were examined, carrying four additional negative charges on the α-subunit (rHbFα4), two additional negative charges on the γ-subunit (rHbFγ2) or a combination of these (rHbFα4/γ2). The increase in negative surface charge in these HbF mutants required the development of an alternate initial capture step in the downstream purification procedures. For the rHbFα4 mutant, we achieved a significantly enhanced yield of purified HbF with no apparent adverse effects on Hb functionality. However, the presence of non-functional Hb portions in the rHbFγ2 and rHbFα4/γ2 samples reduced the yields significantly for those mutants and indicated an imbalanced expression/association of globin chains. Furthermore, the autoxidation studies indicated that the rHbFγ2 and rHbFα4/γ2 mutants also were less oxidatively stable than rHbFα4 and wt rHbF. The study further verified the need for an improved flask culture protocol by optimizing cultivation parameters to enable yield-improving qualities of surface-located mutations.
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Affiliation(s)
- Karin Kettisen
- Division of Pure and Applied Biochemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - Leif Bülow
- Division of Pure and Applied Biochemistry, Department of Chemistry, Lund University, Lund, Sweden
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Evolved increases in hemoglobin-oxygen affinity and the Bohr effect coincided with the aquatic specialization of penguins. Proc Natl Acad Sci U S A 2021; 118:2023936118. [PMID: 33753505 PMCID: PMC8020755 DOI: 10.1073/pnas.2023936118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In diving birds like penguins, physiologic considerations suggest that increased hemoglobin (Hb)-O2 affinity may improve pulmonary O2 extraction and enhance dive capacity. We integrated experimental tests on whole-blood and native Hbs of penguins with protein engineering experiments on reconstructed ancestral Hbs. The experiments involving ancestral protein resurrection enabled us to test for evolved changes in Hb function in the stem lineage of penguins after divergence from their closest nondiving relatives. We demonstrate that penguins evolved an increased Hb-O2 affinity in conjunction with a greatly augmented Bohr effect (i.e., reduction in Hb-O2 affinity at low pH) that should maximize pulmonary O2 extraction without compromising O2 delivery at systemic capillaries. Dive capacities of air-breathing vertebrates are dictated by onboard O2 stores, suggesting that physiologic specialization of diving birds such as penguins may have involved adaptive changes in convective O2 transport. It has been hypothesized that increased hemoglobin (Hb)-O2 affinity improves pulmonary O2 extraction and enhances the capacity for breath-hold diving. To investigate evolved changes in Hb function associated with the aquatic specialization of penguins, we integrated comparative measurements of whole-blood and purified native Hb with protein engineering experiments based on site-directed mutagenesis. We reconstructed and resurrected ancestral Hb representing the common ancestor of penguins and the more ancient ancestor shared by penguins and their closest nondiving relatives (order Procellariiformes, which includes albatrosses, shearwaters, petrels, and storm petrels). These two ancestors bracket the phylogenetic interval in which penguin-specific changes in Hb function would have evolved. The experiments revealed that penguins evolved a derived increase in Hb-O2 affinity and a greatly augmented Bohr effect (i.e., reduced Hb-O2 affinity at low pH). Although an increased Hb-O2 affinity reduces the gradient for O2 diffusion from systemic capillaries to metabolizing cells, this can be compensated by a concomitant enhancement of the Bohr effect, thereby promoting O2 unloading in acidified tissues. We suggest that the evolved increase in Hb-O2 affinity in combination with the augmented Bohr effect maximizes both O2 extraction from the lungs and O2 unloading from the blood, allowing penguins to fully utilize their onboard O2 stores and maximize underwater foraging time.
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7
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Effect of NH2-terminal acetylation on the oxygenation properties of vertebrate haemoglobin. Biochem J 2021; 477:3839-3850. [PMID: 32936244 DOI: 10.1042/bcj20200623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 01/07/2023]
Abstract
In vertebrate haemoglobin (Hb), the NH2-terminal residues of the α- and β-chain subunits are thought to play an important role in the allosteric binding of protons (Bohr effect), CO2 (as carbamino derivatives), chloride ions, and organic phosphates. Accordingly, acetylation of the α- and/or β-chain NH2-termini may have significant effects on the oxygenation properties of Hb. Here we investigate the effect of NH2-terminal acetylation by using a newly developed expression plasmid system that enables us to compare recombinantly expressed Hbs that are structurally identical except for the presence or absence of NH2-terminal acetyl groups. Experiments with native and recombinant Hbs of representative vertebrates reveal that NH2-terminal acetylation does not impair the Bohr effect, nor does it significantly diminish responsiveness to allosteric cofactors, such as chloride ions or organic phosphates. These results suggest that observed variation in the oxygenation properties of vertebrate Hbs is principally explained by amino acid divergence in the constituent globin chains rather than post-translational modifications of the globin chain NH2-termini.
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8
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Zhao X, Zhou J, Du G, Chen J. Recent Advances in the Microbial Synthesis of Hemoglobin. Trends Biotechnol 2020; 39:286-297. [PMID: 32912649 DOI: 10.1016/j.tibtech.2020.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/27/2020] [Accepted: 08/11/2020] [Indexed: 01/08/2023]
Abstract
Hemoglobin is a cofactor-containing protein with heme that plays important roles in transporting and storing oxygen. Hemoglobins have been widely applied as acellular oxygen carriers, bioavailable iron-supplying agents, and food-grade coloring and flavoring agents. To meet increasing demands and overcome the drawbacks of chemical extraction, the biosynthesis of hemoglobin has become an attractive alternative. Several hemoglobins have recently been synthesized by various microorganisms through metabolic engineering and synthetic biology. In this review, we summarize the novel strategies that have been used to biosynthesize hemoglobin. These strategies can also serve as references for producing other heme-binding proteins.
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Affiliation(s)
- Xinrui Zhao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China; National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
| | - Guocheng Du
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jian Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China; National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
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9
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Natarajan C, Signore AV, Kumar V, Storz JF. Synthesis of Recombinant Human Hemoglobin With NH 2 -Terminal Acetylation in Escherichia coli. ACTA ACUST UNITED AC 2020; 101:e112. [PMID: 32687676 DOI: 10.1002/cpps.112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The development of new technologies for the efficient expression of recombinant hemoglobin (rHb) is of interest for experimental studies of protein biochemistry and the development of cell-free blood substitutes in transfusion medicine. Expression of rHb in Escherichia coli host cells has numerous advantages, but one disadvantage of using prokaryotic systems to express eukaryotic proteins is that they are incapable of performing post-translational modifications such as NH2 -terminal acetylation. One possible solution is to coexpress additional enzymes that can perform the necessary modifications in the host cells. Here, we report a new method for synthesizing human rHb with proper NH2 -terminal acetylation. Mass spectrometry experiments involving native and recombinant human Hb confirmed the efficacy of the new technique in producing correctly acetylated globin chains. Finally, functional experiments provided insights into the effects of NH2 -terminal acetylation on O2 binding properties. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Gene synthesis and cloning the cassette to the expression plasmid Basic Protocol 2: Selection of E. coli expression strains for coexpression Basic Protocol 3: Large-scale recombinant hemoglobin expression and purification Support Protocol 1: Measuring O2 equilibration curves Support Protocol 2: Mass spectrometry to confirm NH2 -terminal acetylation.
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Affiliation(s)
| | - Anthony V Signore
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
| | - Vikas Kumar
- Mass Spectrometry and Proteomics Core Facility, University of Nebraska Medical Center, Omaha, Nebraska
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
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10
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Signore AV, Storz JF. Biochemical pedomorphosis and genetic assimilation in the hypoxia adaptation of Tibetan antelope. SCIENCE ADVANCES 2020; 6:eabb5447. [PMID: 32596473 PMCID: PMC7299627 DOI: 10.1126/sciadv.abb5447] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/11/2020] [Indexed: 05/17/2023]
Abstract
Developmental shifts in stage-specific gene expression can provide a ready mechanism of phenotypic change by altering the rate or timing of ontogenetic events. We found that the high-altitude Tibetan antelope (Panthelops hodgsonii) has evolved an adaptive increase in blood-O2 affinity by truncating the ancestral ontogeny of globin gene expression such that a high-affinity juvenile hemoglobin isoform (isoHb) completely supplants the lower-affinity isoHb that is expressed in the adult red blood cells of other bovids. This juvenilization of blood properties represents a canalization of an acclimatization response to hypoxia that has been well documented in adult goats and sheep. We also found the genomic mechanism underlying this regulatory isoHb switch, revealing how a reversible acclimatization response became genetically assimilated as an irreversible adaptation to chronic hypoxia.
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Affiliation(s)
- Anthony V. Signore
- University of Nebraska, School of Biological Sciences, Lincoln, NE 68588, USA
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11
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Pillai AS, Chandler SA, Liu Y, Signore AV, Cortez-Romero CR, Benesch JLP, Laganowsky A, Storz JF, Hochberg GKA, Thornton JW. Origin of complexity in haemoglobin evolution. Nature 2020; 581:480-485. [PMID: 32461643 PMCID: PMC8259614 DOI: 10.1038/s41586-020-2292-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 04/07/2020] [Indexed: 02/02/2023]
Abstract
Most proteins associate into multimeric complexes with specific architectures1,2, which often have functional properties such as cooperative ligand binding or allosteric regulation3. No detailed knowledge is available about how any multimer and its functions arose during evolution. Here we use ancestral protein reconstruction and biophysical assays to elucidate the origins of vertebrate haemoglobin, a heterotetramer of paralogous α- and β-subunits that mediates respiratory oxygen transport and exchange by cooperatively binding oxygen with moderate affinity. We show that modern haemoglobin evolved from an ancient monomer and characterize the historical 'missing link' through which the modern tetramer evolved-a noncooperative homodimer with high oxygen affinity that existed before the gene duplication that generated distinct α- and β-subunits. Reintroducing just two post-duplication historical substitutions into the ancestral protein is sufficient to cause strong tetramerization by creating favourable contacts with more ancient residues on the opposing subunit. These surface substitutions markedly reduce oxygen affinity and even confer cooperativity, because an ancient linkage between the oxygen binding site and the multimerization interface was already an intrinsic feature of the protein's structure. Our findings establish that evolution can produce new complex molecular structures and functions via simple genetic mechanisms that recruit existing biophysical features into higher-level architectures.
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Affiliation(s)
- Arvind S Pillai
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Shane A Chandler
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Yang Liu
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Anthony V Signore
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | | | - Justin L P Benesch
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Georg K A Hochberg
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Joseph W Thornton
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA.
- Department of Human Genetics, University of Chicago, Chicago, IL, USA.
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12
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Zhang G, Zhao X, Li X, Du G, Zhou J, Chen J. Challenges and possibilities for bio-manufacturing cultured meat. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2020.01.026] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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13
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Signore AV, Yang YZ, Yang QY, Qin G, Moriyama H, Ge RL, Storz JF. Adaptive Changes in Hemoglobin Function in High-Altitude Tibetan Canids Were Derived via Gene Conversion and Introgression. Mol Biol Evol 2020; 36:2227-2237. [PMID: 31362306 PMCID: PMC6759075 DOI: 10.1093/molbev/msz097] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A key question in evolutionary biology concerns the relative importance of different sources of adaptive genetic variation, such as de novo mutations, standing variation, and introgressive hybridization. A corollary question concerns how allelic variants derived from these different sources may influence the molecular basis of phenotypic adaptation. Here, we use a protein-engineering approach to examine the phenotypic effect of putatively adaptive hemoglobin (Hb) mutations in the high-altitude Tibetan wolf that were selectively introgressed into the Tibetan mastiff, a high-altitude dog breed that is renowned for its hypoxia tolerance. Experiments revealed that the introgressed coding variants confer an increased Hb–O2 affinity in conjunction with an enhanced Bohr effect. We also document that affinity-enhancing mutations in the β-globin gene of Tibetan wolf were originally derived via interparalog gene conversion from a tandemly linked β-globin pseudogene. Thus, affinity-enhancing mutations were introduced into the β-globin gene of Tibetan wolf via one form of intragenomic lateral transfer (ectopic gene conversion) and were subsequently introduced into the Tibetan mastiff genome via a second form of lateral transfer (introgression). Site-directed mutagenesis experiments revealed that the increased Hb–O2 affinity requires a specific two-site combination of amino acid replacements, suggesting that the molecular underpinnings of Hb adaptation in Tibetan mastiff (involving mutations that arose in a nonexpressed gene and which originally fixed in Tibetan wolf) may be qualitatively distinct from functionally similar changes in protein function that could have evolved via sequential fixation of de novo mutations during the breed’s relatively short duration of residency at high altitude.
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Affiliation(s)
| | - Ying-Zhong Yang
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Quan-Yu Yang
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Ga Qin
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, NE
| | - Ri-Li Ge
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE
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14
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Signore AV, Paijmans JLA, Hofreiter M, Fago A, Weber RE, Springer MS, Campbell KL. Emergence of a Chimeric Globin Pseudogene and Increased Hemoglobin Oxygen Affinity Underlie the Evolution of Aquatic Specializations in Sirenia. Mol Biol Evol 2019; 36:1134-1147. [PMID: 30828717 PMCID: PMC6526914 DOI: 10.1093/molbev/msz044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/13/2019] [Accepted: 02/27/2019] [Indexed: 12/13/2022] Open
Abstract
As limits on O2 availability during submergence impose severe constraints on aerobic respiration, the oxygen binding globin proteins of marine mammals are expected to have evolved under strong evolutionary pressures during their land-to-sea transition. Here, we address this question for the order Sirenia by retrieving, annotating, and performing detailed selection analyses on the globin repertoire of the extinct Steller’s sea cow (Hydrodamalis gigas), dugong (Dugong dugon), and Florida manatee (Trichechus manatus latirostris) in relation to their closest living terrestrial relatives (elephants and hyraxes). These analyses indicate most loci experienced elevated nucleotide substitution rates during their transition to a fully aquatic lifestyle. While most of these genes evolved under neutrality or strong purifying selection, the rate of nonsynonymous/synonymous replacements increased in two genes (Hbz-T1 and Hba-T1) that encode the α-type chains of hemoglobin (Hb) during each stage of life. Notably, the relaxed evolution of Hba-T1 is temporally coupled with the emergence of a chimeric pseudogene (Hba-T2/Hbq-ps) that contributed to the tandemly linked Hba-T1 of stem sirenians via interparalog gene conversion. Functional tests on recombinant Hb proteins from extant and ancestral sirenians further revealed that the molecular remodeling of Hba-T1 coincided with increased Hb–O2 affinity in early sirenians. Available evidence suggests that this trait evolved to maximize O2 extraction from finite lung stores and suppress tissue O2 offloading, thereby facilitating the low metabolic intensities of extant sirenians. In contrast, the derived reduction in Hb–O2 affinity in (sub)Arctic Steller’s sea cows is consistent with fueling increased thermogenesis by these once colossal marine herbivores.
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Affiliation(s)
- Anthony V Signore
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada.,School of Biological Sciences, University of Nebraska, Lincoln, NE
| | | | - Michael Hofreiter
- Institute of Biochemistry and Biology, University of Potsdam, Germany
| | - Angela Fago
- Department of Bioscience, Zoophysiology, Aarhus University, Denmark
| | - Roy E Weber
- Department of Bioscience, Zoophysiology, Aarhus University, Denmark
| | - Mark S Springer
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA
| | - Kevin L Campbell
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada
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15
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Storz JF, Natarajan C, Signore AV, Witt CC, McCandlish DM, Stoltzfus A. The role of mutation bias in adaptive molecular evolution: insights from convergent changes in protein function. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180238. [PMID: 31154983 DOI: 10.1098/rstb.2018.0238] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
An underexplored question in evolutionary genetics concerns the extent to which mutational bias in the production of genetic variation influences outcomes and pathways of adaptive molecular evolution. In the genomes of at least some vertebrate taxa, an important form of mutation bias involves changes at CpG dinucleotides: if the DNA nucleotide cytosine (C) is immediately 5' to guanine (G) on the same coding strand, then-depending on methylation status-point mutations at both sites occur at an elevated rate relative to mutations at non-CpG sites. Here, we examine experimental data from case studies in which it has been possible to identify the causative substitutions that are responsible for adaptive changes in the functional properties of vertebrate haemoglobin (Hb). Specifically, we examine the molecular basis of convergent increases in Hb-O2 affinity in high-altitude birds. Using a dataset of experimentally verified, affinity-enhancing mutations in the Hbs of highland avian taxa, we tested whether causative changes are enriched for mutations at CpG dinucleotides relative to the frequency of CpG mutations among all possible missense mutations. The tests revealed that a disproportionate number of causative amino acid replacements were attributable to CpG mutations, suggesting that mutation bias can influence outcomes of molecular adaptation. This article is part of the theme issue 'Convergent evolution in the genomics era: new insights and directions'.
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Affiliation(s)
- Jay F Storz
- 1 School of Biological Sciences, University of Nebraska , Lincoln, NE 68588 , USA
| | | | - Anthony V Signore
- 1 School of Biological Sciences, University of Nebraska , Lincoln, NE 68588 , USA
| | - Christopher C Witt
- 2 Department of Biology, University of New Mexico , Albuquerque, NM 87131 , USA.,3 Museum of Southwestern Biology, University of New Mexico , Albuquerque, NM 87131 , USA
| | | | - Arlin Stoltzfus
- 5 Office of Data and Informatics, Material Measurement Laboratory, NIST, and Institute for Bioscience and Biotechnology Research , Rockville, MD 20850 , USA
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16
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Chromatographic separation of hemoglobin variants using robust molecularly imprinted polymers. Talanta 2019; 199:27-31. [PMID: 30952256 DOI: 10.1016/j.talanta.2019.01.125] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 11/20/2022]
Abstract
Devising a robust, efficient and cost effective hemoglobin (Hb) purification strategy is one of the key challenges in the development of Hb-based blood substitutes. The aim of this study was to use molecularly imprinted polymers (MIPs) as a novel and efficient chromatographic resin to selectively recognize and purify different Hb variants. The results showed that the Hb-MIP material developed here could selectively recognize and purify various Hb directly from either crude E. coli extracts or human body fluids, such as blood plasma and cerebrospinal fluid (CSF), in one-step. The dynamic binding capacity at 10% breakthrough was around 7.4 mg mL-1resin for adult Hb (HbA) and fetal Hb (HbF). This chromatographic material also allowed identification of changes related to amino acid substitutions on the Hb protein surface. For instance, when an additional lysine residue was introduced, the HbA αY42K mutant eluted later in an Hb-MIP column than wildtype HbA. Additional negative charges on the protein surface, such as aspartate, mitigated the interaction between the protein and imprinted polymers, and therefore an αA19D-αA12D HbF mutant eluted earlier, at -2.7 column volumes compared to wildtype HbF.
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17
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Hickey JM, Toprani VM, Kaur K, Mishra RP, Goel A, Oganesyan N, Lees A, Sitrin R, Joshi SB, Volkin DB. Analytical Comparability Assessments of 5 Recombinant CRM 197 Proteins From Different Manufacturers and Expression Systems. J Pharm Sci 2018. [DOI: 10.1016/j.xphs.2018.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Molecular basis of hemoglobin adaptation in the high-flying bar-headed goose. PLoS Genet 2018; 14:e1007331. [PMID: 29608560 PMCID: PMC5903655 DOI: 10.1371/journal.pgen.1007331] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/17/2018] [Accepted: 03/23/2018] [Indexed: 01/14/2023] Open
Abstract
During the adaptive evolution of a particular trait, some selectively fixed mutations may be directly causative and others may be purely compensatory. The relative contribution of these two classes of mutation to adaptive phenotypic evolution depends on the form and prevalence of mutational pleiotropy. To investigate the nature of adaptive substitutions and their pleiotropic effects, we used a protein engineering approach to characterize the molecular basis of hemoglobin (Hb) adaptation in the high-flying bar-headed goose (Anser indicus), a hypoxia-tolerant species renowned for its trans-Himalayan migratory flights. To test the effects of observed substitutions on evolutionarily relevant genetic backgrounds, we synthesized all possible genotypic intermediates in the line of descent connecting the wildtype bar-headed goose genotype with the most recent common ancestor of bar-headed goose and its lowland relatives. Site-directed mutagenesis experiments revealed one major-effect mutation that significantly increased Hb-O2 affinity on all possible genetic backgrounds. Two other mutations exhibited smaller average effect sizes and less additivity across backgrounds. One of the latter mutations produced a concomitant increase in the autoxidation rate, a deleterious side-effect that was fully compensated by a second-site mutation at a spatially proximal residue. The experiments revealed three key insights: (i) subtle, localized structural changes can produce large functional effects; (ii) relative effect sizes of function-altering mutations may depend on the sequential order in which they occur; and (iii) compensation of deleterious pleiotropic effects may play an important role in the adaptive evolution of protein function.
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19
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Divergent and parallel routes of biochemical adaptation in high-altitude passerine birds from the Qinghai-Tibet Plateau. Proc Natl Acad Sci U S A 2018; 115:1865-1870. [PMID: 29432191 DOI: 10.1073/pnas.1720487115] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
When different species experience similar selection pressures, the probability of evolving similar adaptive solutions may be influenced by legacies of evolutionary history, such as lineage-specific changes in genetic background. Here we test for adaptive convergence in hemoglobin (Hb) function among high-altitude passerine birds that are native to the Qinghai-Tibet Plateau, and we examine whether convergent increases in Hb-O2 affinity have a similar molecular basis in different species. We documented that high-altitude parid and aegithalid species from the Qinghai-Tibet Plateau have evolved derived increases in Hb-O2 affinity in comparison with their closest lowland relatives in East Asia. However, convergent increases in Hb-O2 affinity and convergence in underlying functional mechanisms were seldom attributable to the same amino acid substitutions in different species. Using ancestral protein resurrection and site-directed mutagenesis, we experimentally confirmed two cases in which parallel substitutions contributed to convergent increases in Hb-O2 affinity in codistributed high-altitude species. In one case involving the ground tit (Parus humilis) and gray-crested tit (Lophophanes dichrous), parallel amino acid replacements with affinity-enhancing effects were attributable to nonsynonymous substitutions at a CpG dinucleotide, suggesting a possible role for mutation bias in promoting recurrent changes at the same site. Overall, most altitude-related changes in Hb function were caused by divergent amino acid substitutions, and a select few were caused by parallel substitutions that produced similar phenotypic effects on the divergent genetic backgrounds of different species.
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20
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Bracke A, Hoogewijs D, Dewilde S. Exploring three different expression systems for recombinant expression of globins: Escherichia coli, Pichia pastoris and Spodoptera frugiperda. Anal Biochem 2017; 543:62-70. [PMID: 29203135 DOI: 10.1016/j.ab.2017.11.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 12/17/2022]
Abstract
Globins are among the best investigated proteins in biological and medical sciences and represent a prime tool for the study of the evolution of genes and the structure-function relationship of proteins. Here, we explore the recombinant expression of globins in three different expression systems: Escherichia coli, Pichia pastoris and the baculovirus infected Spodoptera frugiperda. We expressed two different human globin types in these three expression systems: I) the well-characterized neuroglobin and II) the uncharacterized, circular permutated globin domain of the large chimeric globin androglobin. It is clear from the literature that E.coli is the most used expression system for expression and purification of recombinant globins. However, the major disadvantage of E. coli is the formation of insoluble aggregates. We experienced that, for more complex multi-domain globins, like the chimeric globin androglobin, it is recommended to switch to a higher eukaryotic expression system.
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Affiliation(s)
- An Bracke
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, Antwerp 2610, Belgium
| | - David Hoogewijs
- Department of Medicine/Physiology, University of Fribourg, Chemin du Musée 5, CH 1700 Fribourg, Switzerland
| | - Sylvia Dewilde
- Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, Antwerp 2610, Belgium.
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21
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Acclimation to prolonged hypoxia alters hemoglobin isoform expression and increases hemoglobin oxygen affinity and aerobic performance in a marine fish. Sci Rep 2017; 7:7834. [PMID: 28798467 PMCID: PMC5552867 DOI: 10.1038/s41598-017-07696-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/03/2017] [Indexed: 12/21/2022] Open
Abstract
Hemoglobin (Hb) multiplicity is common in fish, yet despite its ubiquitous nature, the functional significance is unclear. Here we explore the hypothesis that Hb multiplicity plays a role in hypoxia tolerance using the red drum (Sciaenops ocellatus). Red drum is an economically and ecologically important species native to coastal regions and estuaries of the Gulf of Mexico – habitats that routinely experience pronounced hypoxic events. Using a transcriptomic approach, we demonstrate that red drum red blood cells express 7 and 5 Hbα and Hbβ isoforms, respectively. Phylogenetic analysis grouped these isoforms into distinct isoHb clades, and provided evidence of lineage specific expression of particular isoHbs. In normoxia, three isoHbs predominated (Hbα-3.1, -3.2, and Hbβ-3.1). A three-week hypoxia acclimation (48 mmHg) resulted in significant up-regulation of Hbα-2, Hbα-3.2, and Hbβ-3.1, effectively switching the predominantly expressed isoforms. Changes in subunit expression were correlated with a decrease in non-stripped hemolysate P50. Similarly, hypoxia acclimation resulted in a 20% reduction in whole animal critical oxygen threshold (Pcrit). Hypoxia acclimation was not associated with changes in gill morphology, hematocrit, or relative ventricular mass. Overall, these data provide support for the hypothesis that Hb isoform switching can provide a physiological benefit to counteract environmental stress in fishes.
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22
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Kumar A, Natarajan C, Moriyama H, Witt CC, Weber RE, Fago A, Storz JF. Stability-Mediated Epistasis Restricts Accessible Mutational Pathways in the Functional Evolution of Avian Hemoglobin. Mol Biol Evol 2017; 34:1240-1251. [PMID: 28201714 PMCID: PMC5400398 DOI: 10.1093/molbev/msx085] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
If the fitness effects of amino acid mutations are conditional on genetic background, then mutations can have different effects depending on the sequential order in which they occur during evolutionary transitions in protein function. A key question concerns the fraction of possible mutational pathways connecting alternative functional states that involve transient reductions in fitness. Here we examine the functional effects of multiple amino acid substitutions that contributed to an evolutionary transition in the oxygenation properties of avian hemoglobin (Hb). The set of causative changes included mutations at intradimer interfaces of the Hb tetramer. Replacements at such sites may be especially likely to have epistatic effects on Hb function since residues at intersubunit interfaces are enmeshed in networks of salt bridges and hydrogen bonds between like and unlike subunits; mutational reconfigurations of these atomic contacts can affect allosteric transitions in quaternary structure and the propensity for tetramer-dimer dissociation. We used ancestral protein resurrection in conjunction with a combinatorial protein engineering approach to synthesize genotypes representing the complete set of mutational intermediates in all possible forward pathways that connect functionally distinct ancestral and descendent genotypes. The experiments revealed that 1/2 of all possible forward pathways included mutational intermediates with aberrant functional properties because particular combinations of mutations promoted tetramer-dimer dissociation. The subset of mutational pathways with unstable intermediates may be selectively inaccessible, representing evolutionary roads not taken. The experimental results also demonstrate how epistasis for particular functional properties of proteins may be mediated indirectly by mutational effects on quaternary structural stability.
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Affiliation(s)
- Amit Kumar
- School of Biological Sciences, University of Nebraska, Lincoln, NE
| | | | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, NE
| | - Christopher C. Witt
- Department of Biology, University of New Mexico, Albuquerque, NM
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM
| | - Roy E. Weber
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE
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23
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Natarajan C, Hoffmann FG, Weber RE, Fago A, Witt CC, Storz JF. Predictable convergence in hemoglobin function has unpredictable molecular underpinnings. Science 2017; 354:336-339. [PMID: 27846568 DOI: 10.1126/science.aaf9070] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/20/2016] [Indexed: 12/28/2022]
Abstract
To investigate the predictability of genetic adaptation, we examined the molecular basis of convergence in hemoglobin function in comparisons involving 56 avian taxa that have contrasting altitudinal range limits. Convergent increases in hemoglobin-oxygen affinity were pervasive among high-altitude taxa, but few such changes were attributable to parallel amino acid substitutions at key residues. Thus, predictable changes in biochemical phenotype do not have a predictable molecular basis. Experiments involving resurrected ancestral proteins revealed that historical substitutions have context-dependent effects, indicating that possible adaptive solutions are contingent on prior history. Mutations that produce an adaptive change in one species may represent precluded possibilities in other species because of differences in genetic background.
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Affiliation(s)
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology and Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA
| | - Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, DK-8000 Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, DK-8000 Aarhus, Denmark
| | - Christopher C Witt
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
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24
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Inoguchi N, Mizuno N, Baba S, Kumasaka T, Natarajan C, Storz JF, Moriyama H. Alteration of the α1β2/α2β1 subunit interface contributes to the increased hemoglobin-oxygen affinity of high-altitude deer mice. PLoS One 2017; 12:e0174921. [PMID: 28362841 PMCID: PMC5376325 DOI: 10.1371/journal.pone.0174921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 03/17/2017] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Deer mice (Peromyscus maniculatus) that are native to high altitudes in the Rocky Mountains have evolved hemoglobins with an increased oxygen-binding affinity relative to those of lowland conspecifics. To elucidate the molecular mechanisms responsible for the evolved increase in hemoglobin-oxygen affinity, the crystal structure of the highland hemoglobin variant was solved and compared with the previously reported structure for the lowland variant. RESULTS Highland hemoglobin yielded at least two crystal types, in which the longest axes were 507 and 230 Å. Using the smaller unit cell crystal, the structure was solved at 2.2 Å resolution. The asymmetric unit contained two tetrameric hemoglobin molecules. CONCLUSIONS The analyses revealed that αPro50 in the highland hemoglobin variant promoted a stable interaction between αHis45 and heme that was not seen in the αHis50 lowland variant. The αPro50 mutation also altered the nature of atomic contacts at the α1β2/α2β1 intersubunit interfaces. These results demonstrate how affinity-altering changes in intersubunit interactions can be produced by mutations at structurally remote sites.
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Affiliation(s)
- Noriko Inoguchi
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Nobuhiro Mizuno
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Sayo, Japan
| | - Seiki Baba
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Sayo, Japan
| | - Takashi Kumasaka
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Sayo, Japan
| | - Chandrasekhar Natarajan
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
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25
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Natarajan C, Projecto-Garcia J, Moriyama H, Weber RE, Muñoz-Fuentes V, Green AJ, Kopuchian C, Tubaro PL, Alza L, Bulgarella M, Smith MM, Wilson RE, Fago A, McCracken KG, Storz JF. Convergent Evolution of Hemoglobin Function in High-Altitude Andean Waterfowl Involves Limited Parallelism at the Molecular Sequence Level. PLoS Genet 2015; 11:e1005681. [PMID: 26637114 PMCID: PMC4670201 DOI: 10.1371/journal.pgen.1005681] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/27/2015] [Indexed: 11/18/2022] Open
Abstract
A fundamental question in evolutionary genetics concerns the extent to which adaptive phenotypic convergence is attributable to convergent or parallel changes at the molecular sequence level. Here we report a comparative analysis of hemoglobin (Hb) function in eight phylogenetically replicated pairs of high- and low-altitude waterfowl taxa to test for convergence in the oxygenation properties of Hb, and to assess the extent to which convergence in biochemical phenotype is attributable to repeated amino acid replacements. Functional experiments on native Hb variants and protein engineering experiments based on site-directed mutagenesis revealed the phenotypic effects of specific amino acid replacements that were responsible for convergent increases in Hb-O2 affinity in multiple high-altitude taxa. In six of the eight taxon pairs, high-altitude taxa evolved derived increases in Hb-O2 affinity that were caused by a combination of unique replacements, parallel replacements (involving identical-by-state variants with independent mutational origins in different lineages), and collateral replacements (involving shared, identical-by-descent variants derived via introgressive hybridization). In genome scans of nucleotide differentiation involving high- and low-altitude populations of three separate species, function-altering amino acid polymorphisms in the globin genes emerged as highly significant outliers, providing independent evidence for adaptive divergence in Hb function. The experimental results demonstrate that convergent changes in protein function can occur through multiple historical paths, and can involve multiple possible mutations. Most cases of convergence in Hb function did not involve parallel substitutions and most parallel substitutions did not affect Hb-O2 affinity, indicating that the repeatability of phenotypic evolution does not require parallelism at the molecular level. The convergent evolution of similar traits in different species could be due to repeated changes at the genetic level or different changes that produce the same phenotypic effect. To investigate the extent to which convergence in phenotype is caused by repeated mutations, we investigated the molecular basis of convergent changes in the oxygenation properties of hemoglobin (Hb) in eight pairs of high- and low-altitude waterfowl taxa from the Andes. The results revealed that convergent increases in Hb-O2 affinity in highland taxa involved a combination of unique and repeated amino acid replacements. However, convergent changes in Hb function generally did not involve parallel substitutions, indicating that repeatability in the evolution of protein function does not require repeatability at the sequence level.
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Affiliation(s)
- Chandrasekhar Natarajan
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Joana Projecto-Garcia
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Roy E. Weber
- Department of Bioscience, Zoophysiology, Aarhus University, Aarhus, Denmark
| | - Violeta Muñoz-Fuentes
- Estación Biológica de Doñana-CSIC, Sevilla, Spain
- Conservation Genetics Group, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany
| | | | - Cecilia Kopuchian
- Centro de Ecología Aplicada del Litoral (CECOAL), Consejo Nacional de Investigaciones Cientificas y Técnicas (CONICET), Corrientes, Argentina
| | - Pablo L. Tubaro
- División Ornitología, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ (MACN-CONICET), Buenos Aires, Argentina
| | - Luis Alza
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Mariana Bulgarella
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Matthew M. Smith
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Robert E. Wilson
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
| | - Angela Fago
- Department of Bioscience, Zoophysiology, Aarhus University, Aarhus, Denmark
| | - Kevin G. McCracken
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, Florida, United States of America
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
- * E-mail:
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26
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Contribution of a mutational hot spot to hemoglobin adaptation in high-altitude Andean house wrens. Proc Natl Acad Sci U S A 2015; 112:13958-63. [PMID: 26460028 DOI: 10.1073/pnas.1507300112] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A key question in evolutionary genetics is why certain mutations or certain types of mutation make disproportionate contributions to adaptive phenotypic evolution. In principle, the preferential fixation of particular mutations could stem directly from variation in the underlying rate of mutation to function-altering alleles. However, the influence of mutation bias on the genetic architecture of phenotypic evolution is difficult to evaluate because data on rates of mutation to function-altering alleles are seldom available. Here, we report the discovery that a single point mutation at a highly mutable site in the β(A)-globin gene has contributed to an evolutionary change in hemoglobin (Hb) function in high-altitude Andean house wrens (Troglodytes aedon). Results of experiments on native Hb variants and engineered, recombinant Hb mutants demonstrate that a nonsynonymous mutation at a CpG dinucleotide in the β(A)-globin gene is responsible for an evolved difference in Hb-O2 affinity between high- and low-altitude house wren populations. Moreover, patterns of genomic differentiation between high- and low-altitude populations suggest that altitudinal differentiation in allele frequencies at the causal amino acid polymorphism reflects a history of spatially varying selection. The experimental results highlight the influence of mutation rate on the genetic basis of phenotypic evolution by demonstrating that a large-effect allele at a highly mutable CpG site has promoted physiological differentiation in blood O2 transport capacity between house wren populations that are native to different elevations.
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27
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Storz JF, Natarajan C, Moriyama H, Hoffmann FG, Wang T, Fago A, Malte H, Overgaard J, Weber RE. Oxygenation properties and isoform diversity of snake hemoglobins. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1178-91. [PMID: 26354849 DOI: 10.1152/ajpregu.00327.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/02/2015] [Indexed: 11/22/2022]
Abstract
Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis platura (Elapidae). We analyzed allosteric properties of snake Hbs in terms of the Monod-Wyman-Changeux model and Adair four-step thermodynamic model. Hbs from each of the three species exhibited high intrinsic O2 affinities, low cooperativities, small Bohr factors in the absence of phosphates, and high sensitivities to ATP. Oxygenation properties of the snake Hbs could be explained entirely by allosteric transitions in the quaternary structure of intact tetramers, suggesting that ligation-dependent dissociation of Hb tetramers into αβ-dimers is not a universal feature of snake Hbs. Surprisingly, the major Hb isoform of the South American rattlesnake is homologous to the minor HbD of other amniotes and, contrary to the pattern of Hb isoform differentiation in birds and turtles, exhibits a lower O2 affinity than the HbA isoform.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska;
| | | | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, Mississippi; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, Mississippi; and
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Hans Malte
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Johannes Overgaard
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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28
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Natarajan C, Hoffmann FG, Lanier HC, Wolf CJ, Cheviron ZA, Spangler ML, Weber RE, Fago A, Storz JF. Intraspecific polymorphism, interspecific divergence, and the origins of function-altering mutations in deer mouse hemoglobin. Mol Biol Evol 2015; 32:978-97. [PMID: 25556236 PMCID: PMC4379404 DOI: 10.1093/molbev/msu403] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Major challenges for illuminating the genetic basis of phenotypic evolution are to identify causative mutations, to quantify their functional effects, to trace their origins as new or preexisting variants, and to assess the manner in which segregating variation is transduced into species differences. Here, we report an experimental analysis of genetic variation in hemoglobin (Hb) function within and among species of Peromyscus mice that are native to different elevations. A multilocus survey of sequence variation in the duplicated HBA and HBB genes in Peromyscus maniculatus revealed that function-altering amino acid variants are widely shared among geographically disparate populations from different elevations, and numerous amino acid polymorphisms are also shared with closely related species. Variation in Hb-O2 affinity within and among populations of P. maniculatus is attributable to numerous amino acid mutations that have individually small effects. One especially surprising feature of the Hb polymorphism in P. maniculatus is that an appreciable fraction of functional standing variation in the two transcriptionally active HBA paralogs is attributable to recurrent gene conversion from a tandemly linked HBA pseudogene. Moreover, transpecific polymorphism in the duplicated HBA genes is not solely attributable to incomplete lineage sorting or introgressive hybridization; instead, it is mainly attributable to recurrent interparalog gene conversion that has occurred independently in different species. Partly as a result of concerted evolution between tandemly duplicated globin genes, the same amino acid changes that contribute to variation in Hb function within P. maniculatus also contribute to divergence in Hb function among different species of Peromyscus. In the case of function-altering Hb mutations in Peromyscus, there is no qualitative or quantitative distinction between segregating variants within species and fixed differences between species.
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Affiliation(s)
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University
| | - Hayley C Lanier
- Department of Zoology and Physiology, University of Wyoming at Casper
| | - Cole J Wolf
- Department of Animal Biology, School of Integrative Biology, University of Illinois, Urbana-Champaign
| | - Zachary A Cheviron
- Department of Animal Biology, School of Integrative Biology, University of Illinois, Urbana-Champaign
| | | | - Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln
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29
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Tufts DM, Natarajan C, Revsbech IG, Projecto-Garcia J, Hoffmann FG, Weber RE, Fago A, Moriyama H, Storz JF. Epistasis constrains mutational pathways of hemoglobin adaptation in high-altitude pikas. Mol Biol Evol 2014; 32:287-98. [PMID: 25415962 PMCID: PMC4298171 DOI: 10.1093/molbev/msu311] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A fundamental question in evolutionary genetics concerns the roles of mutational pleiotropy and epistasis in shaping trajectories of protein evolution. This question can be addressed most directly by using site-directed mutagenesis to explore the mutational landscape of protein function in experimentally defined regions of sequence space. Here, we evaluate how pleiotropic trade-offs and epistatic interactions influence the accessibility of alternative mutational pathways during the adaptive evolution of hemoglobin (Hb) function in high-altitude pikas (Mammalia: Lagomorpha). By combining ancestral protein resurrection with a combinatorial protein-engineering approach, we examined the functional effects of sequential mutational steps in all possible pathways that produced an increased Hb–O2 affinity. These experiments revealed that the effects of mutations on Hb–O2 affinity are highly dependent on the temporal order in which they occur: Each of three β-chain substitutions produced a significant increase in Hb–O2 affinity on the ancestral genetic background, but two of these substitutions produced opposite effects when they occurred as later steps in the pathway. The experiments revealed pervasive epistasis for Hb–O2 affinity, but affinity-altering mutations produced no significant pleiotropic trade-offs. These results provide insights into the properties of adaptive substitutions in naturally evolved proteins and suggest that the accessibility of alternative mutational pathways may be more strongly constrained by sign epistasis for positively selected biochemical phenotypes than by antagonistic pleiotropy.
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Affiliation(s)
| | | | - Inge G Revsbech
- Department of Bioscience, Zoophysiology, Aarhus University, Aarhus, Denmark
| | | | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University
| | - Roy E Weber
- Department of Bioscience, Zoophysiology, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Department of Bioscience, Zoophysiology, Aarhus University, Aarhus, Denmark
| | | | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln
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30
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Cheviron ZA, Natarajan C, Projecto-Garcia J, Eddy DK, Jones J, Carling MD, Witt CC, Moriyama H, Weber RE, Fago A, Storz JF. Integrating evolutionary and functional tests of adaptive hypotheses: a case study of altitudinal differentiation in hemoglobin function in an Andean Sparrow, Zonotrichia capensis. Mol Biol Evol 2014; 31:2948-62. [PMID: 25135942 PMCID: PMC4209134 DOI: 10.1093/molbev/msu234] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In air-breathing vertebrates, the physiologically optimal blood-O2 affinity is jointly determined by the prevailing partial pressure of atmospheric O2, the efficacy of pulmonary O2 transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufous-collared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated a population genomic analysis that included all postnatally expressed Hb genes with functional studies of naturally occurring Hb variants, as well as recombinant Hb (rHb) mutants that were engineered through site-directed mutagenesis. We identified three clinally varying amino acid polymorphisms: Two in the α(A)-globin gene, which encodes the α-chain subunits of the major HbA isoform, and one in the α(D)-globin gene, which encodes the α-chain subunits of the minor HbD isoform. We then constructed and experimentally tested single- and double-mutant rHbs representing each of the alternative α(A)-globin genotypes that predominate at different elevations. Although the locus-specific patterns of altitudinal differentiation suggested a history of spatially varying selection acting on Hb polymorphism, the experimental tests demonstrated that the observed amino acid mutations have no discernible effect on respiratory properties of the HbA or HbD isoforms. These results highlight the importance of experimentally validating the hypothesized effects of genetic changes in protein function to avoid the pitfalls of adaptive storytelling.
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Affiliation(s)
- Zachary A Cheviron
- Department of Animal Biology, School of Integrative Biology, University of Illinois, Urbana-Champaign School of Biological Sciences, University of Nebraska, Lincoln
| | | | | | - Douglas K Eddy
- Department of Animal Biology, School of Integrative Biology, University of Illinois, Urbana-Champaign
| | - Jennifer Jones
- Department of Animal Biology, School of Integrative Biology, University of Illinois, Urbana-Champaign
| | | | - Christopher C Witt
- Department of Biology, University of New Mexico Museum of Southwestern Biology, University of New Mexico
| | | | - Roy E Weber
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln
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31
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Zheng X, Dong S, Zheng J, Li D, Li F, Luo Z. Expression, stabilization and purification of membrane proteins via diverse protein synthesis systems and detergents involving cell-free associated with self-assembly peptide surfactants. Biotechnol Adv 2014; 32:564-74. [PMID: 24566241 DOI: 10.1016/j.biotechadv.2014.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 06/13/2013] [Accepted: 02/17/2014] [Indexed: 12/21/2022]
Abstract
G-protein coupled receptors (GPCRs) are involved in regulating most of physiological actions and metabolism in the bodies, which have become most frequently addressed therapeutic targets for various disorders and diseases. Purified GPCR-based drug discoveries have become routine that approaches to structural study, novel biophysical and biochemical function analyses. However, several bottlenecks that GPCR-directed drugs need to conquer the problems including overexpression, solubilization, and purification as well as stabilization. The breakthroughs are to obtain efficient protein yield and stabilize their functional conformation which are both urgently requiring of effective protein synthesis system methods and optimal surfactants. Cell-free protein synthesis system is superior to the high yields and post-translation modifications, and early signs of self-assembly peptide detergents also emerged to superiority in purification of membrane proteins. We herein focus several predominant protein synthesis systems and surfactants involving the novel peptide detergents, and uncover the advantages of cell-free protein synthesis system with self-assembling peptide detergents in purification of functional GPCRs. This review is useful to further study in membrane proteins as well as the new drug exploration.
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Affiliation(s)
- Xuan Zheng
- College of Basic Medical Sciences, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, China
| | - Shuangshuang Dong
- College of Basic Medical Sciences, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, China
| | - Jie Zheng
- College of laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Duanhua Li
- Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Feng Li
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou, China
| | - Zhongli Luo
- College of Basic Medical Sciences, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, China.
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32
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Repeated elevational transitions in hemoglobin function during the evolution of Andean hummingbirds. Proc Natl Acad Sci U S A 2013; 110:20669-74. [PMID: 24297909 DOI: 10.1073/pnas.1315456110] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animals that sustain high levels of aerobic activity under hypoxic conditions (e.g., birds that fly at high altitude) face the physiological challenge of jointly optimizing blood-O2 affinity for O2 loading in the pulmonary circulation and O2 unloading in the systemic circulation. At high altitude, this challenge is especially acute for small endotherms like hummingbirds that have exceedingly high mass-specific metabolic rates. Here we report an experimental analysis of hemoglobin (Hb) function in South American hummingbirds that revealed a positive correlation between Hb-O2 affinity and native elevation. Protein engineering experiments and ancestral-state reconstructions revealed that this correlation is attributable to derived increases in Hb-O2 affinity in highland lineages, as well as derived reductions in Hb-O2 affinity in lowland lineages. Site-directed mutagenesis experiments demonstrated that repeated evolutionary transitions in biochemical phenotype are mainly attributable to repeated amino acid replacements at two epistatically interacting sites that alter the allosteric regulation of Hb-O2 affinity. These results demonstrate that repeated changes in biochemical phenotype involve parallelism at the molecular level, and that mutations with indirect, second-order effects on Hb allostery play key roles in biochemical adaptation.
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33
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Natarajan C, Inoguchi N, Weber RE, Fago A, Moriyama H, Storz JF. Epistasis among adaptive mutations in deer mouse hemoglobin. Science 2013; 340:1324-7. [PMID: 23766324 DOI: 10.1126/science.1236862] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epistatic interactions between mutant sites in the same protein can exert a strong influence on pathways of molecular evolution. We performed protein engineering experiments that revealed pervasive epistasis among segregating amino acid variants that contribute to adaptive functional variation in deer mouse hemoglobin (Hb). Amino acid mutations increased or decreased Hb-O2 affinity depending on the allelic state of other sites. Structural analysis revealed that epistasis for Hb-O2 affinity and allosteric regulatory control is attributable to indirect interactions between structurally remote sites. The prevalence of sign epistasis for fitness-related biochemical phenotypes has important implications for the evolutionary dynamics of protein polymorphism in natural populations.
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34
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Inoguchi N, Oshlo JR, Natarajan C, Weber RE, Fago A, Storz JF, Moriyama H. Deer mouse hemoglobin exhibits a lowered oxygen affinity owing to mobility of the E helix. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:393-8. [PMID: 23545644 PMCID: PMC3614163 DOI: 10.1107/s1744309113005708] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 02/27/2013] [Indexed: 11/10/2022]
Abstract
The deer mouse, Peromyscus maniculatus, exhibits altitude-associated variation in hemoglobin oxygen affinity. To examine the structural basis of this functional variation, the structure of the hemoglobin was solved. Recombinant hemoglobin was expressed in Escherichia coli and was purified by ion-exchange chromatography. Recombinant hemoglobin was crystallized by the hanging-drop vapor-diffusion method using polyethylene glycol as a precipitant. The obtained orthorhombic crystal contained two subunits in the asymmetric unit. The refined structure was interpreted as the aquo-met form. Structural comparisons were performed among hemoglobins from deer mouse, house mouse and human. In contrast to human hemoglobin, deer mouse hemoglobin lacks the hydrogen bond between α1Trp14 in the A helix and α1Thr67 in the E helix owing to the Thr67Ala substitution. In addition, deer mouse hemoglobin has a unique hydrogen bond at the α1β1 interface between residues α1Cys34 and β1Ser128.
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Affiliation(s)
- Noriko Inoguchi
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Jake R. Oshlo
- Nebraska Wesleyan University, Lincoln, Nebraska, USA
| | | | - Roy E. Weber
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Hideaki Moriyama
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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35
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Li J, Zheng L, Li P, Wang F. Intein-mediated expression, purification, and characterization of thymosin α1–thymopentin fusion peptide in Escherichia coli. Protein Expr Purif 2012; 84:1-8. [DOI: 10.1016/j.pep.2012.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
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36
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Badalucco L, Poudel I, Yamanishi M, Natarajan C, Moriyama H. Crystallization of Chlorella deoxyuridine triphosphatase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1599-602. [PMID: 22139176 PMCID: PMC3232149 DOI: 10.1107/s1744309111038097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 09/18/2011] [Indexed: 11/10/2022]
Abstract
Deoxyuridine triphosphatase (dUTPase) is a ubiquitous enzyme that has been widely studied owing to its function and evolutionary significance. The gene coding for the dUTPase from the Chlorella alga was codon-optimized and synthesized. The synthetic gene was expressed in Escherichia coli and recombinant core Chlorella dUTPase (chdUTPase) was purified. Crystallization of chdUTPase was performed by the repetitive hanging-drop vapor-diffusion method at 298 K with ammonium sulfate as the precipitant. In the presence of 2'-deoxyuridine-5'-[(α,β)-imido]triphosphate and magnesium, the enzyme produced die-shaped hexagonal R3 crystals with unit-cell parameters a = b = 66.9, c = 93.6 Å, γ = 120°. X-ray diffraction data for chdUTPase were collected to 1.6 Å resolution. The crystallization of chdUTPase with manganese resulted in very fragile clusters of needles.
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Affiliation(s)
- Laura Badalucco
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0118, USA
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37
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Altitudinal variation at duplicated β-globin genes in deer mice: effects of selection, recombination, and gene conversion. Genetics 2011; 190:203-16. [PMID: 22042573 DOI: 10.1534/genetics.111.134494] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spatially varying selection on a given polymorphism is expected to produce a localized peak in the between-population component of nucleotide diversity, and theory suggests that the chromosomal extent of elevated differentiation may be enhanced in cases where tandemly linked genes contribute to fitness variation. An intriguing example is provided by the tandemly duplicated β-globin genes of deer mice (Peromyscus maniculatus), which contribute to adaptive differentiation in blood-oxygen affinity between high- and low-altitude populations. Remarkably, the two β-globin genes segregate the same pair of functionally distinct alleles due to a history of interparalog gene conversion and alleles of the same functional type are in perfect coupling-phase linkage disequilibrium (LD). Here we report a multilocus analysis of nucleotide polymorphism and LD in highland and lowland mice with different genetic backgrounds at the β-globin genes. The analysis of haplotype structure revealed a paradoxical pattern whereby perfect LD between the two β-globin paralogs (which are separated by 16.2 kb) is maintained in spite of the fact that LD within both paralogs decays to background levels over physical distances of less than 1 kb. The survey of nucleotide polymorphism revealed that elevated levels of altitudinal differentiation at each of the β-globin genes drop away quite rapidly in the external flanking regions (upstream of the 5' paralog and downstream of the 3' paralog), but the level of differentiation remains unexpectedly high across the intergenic region. Observed patterns of diversity and haplotype structure are difficult to reconcile with expectations of a two-locus selection model with multiplicative fitness.
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