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Astani EK, Ersali S, Lee YC, Lin PJ, Huang YC, Huang PY, Jafarian V, Hosseinkhani S, Chen CJ. Determination and evaluation of secondary structure content derived from calcium-induced conformational changes in wild-type and mutant mnemiopsin 2 by synchrotron-based Fourier-transform infrared spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140528. [PMID: 32853773 DOI: 10.1016/j.bbapap.2020.140528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/04/2020] [Accepted: 08/18/2020] [Indexed: 11/17/2022]
Abstract
Mnemiopsin 2 from a luminous ctenophore with two functional EF-hand motifs is a calcium-regulated photoprotein that is responsible for emitting a bright blue bioluminescence upon reacting with coelenterazine and calcium ions in Mnemiopsis leidyi. Synchrotron radiation-based Fourier-transform infrared (SR-FTIR) spectroscopy was applied to analyze the distribution of secondary structures, the conformational changes resulting from calcium binding and the structural stabilities in wild-type mnemiopsin 2, as well as its mutant type that possesses three EF-hand motifs. The distribution of secondary structures of these proteins indicates that mutant apo-mnemiopsin 2 has a more stable secondary structure than the wild-type. Analyses of the SR-FTIR spectra revealed that the conformational changes at the secondary structures of both mnemiopsin 2 depend on the calcium concentrations, such that the most noticeable changes in structures of wild-type and mutant mnemiopsin 2 occur at optimum concentrations 6 and 2 mM of calcium chloride, respectively. The addition of calcium to both proteins increases the proportions of their secondary structures in the amide I and II regions. The major amide I bands in the IR spectra of both mnemiopsin‑calcium complexes shift towards smaller wavenumbers, whereas their main amide II bands are identified at larger wavenumbers.
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Affiliation(s)
- Elahe K Astani
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan; Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 14115-175, Iran
| | - Sara Ersali
- Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca 400028, Romania
| | - Yao-Chang Lee
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Pei-Ju Lin
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan; Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yen-Chieh Huang
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Pei-Yu Huang
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Vahab Jafarian
- Department of Biology, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Iran
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 14115-175, Iran.
| | - Chun-Jung Chen
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan City 701, Taiwan; Department of Physics, National Tsing Hua University, Hsinchu 30043, Taiwan; Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30010, Taiwan.
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Macrander JC, Dimond JL, Bingham BL, Reitzel AM. Transcriptome sequencing and characterization of Symbiodinium muscatinei and Elliptochloris marina, symbionts found within the aggregating sea anemone Anthopleura elegantissima. Mar Genomics 2017; 37:82-91. [PMID: 28888836 DOI: 10.1016/j.margen.2017.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 08/26/2017] [Accepted: 08/27/2017] [Indexed: 12/20/2022]
Abstract
There is a growing body of literature using transcriptomic data to study how tropical cnidarians and their photosynthetic endosymbionts respond to environmental stressors and participate in metabolic exchange. Despite these efforts, our understanding of how essential genes function to facilitate symbiosis establishment and maintenance remains limited. The inclusion of taxonomically and ecologically diverse endosymbionts will enhance our understanding of these interactions. Here we characterize the transcriptomes of two very different symbionts found within the temperate sea anemone Anthopleura elegantissima: the chlorophyte Elliptochloris marina and the dinoflagellate Symbiodinium muscatinei. We use a multi-level approach to assess the diversity of genes found across S. muscatinei and E. marina transcriptomes, and compare their overall protein domains with other dinoflagellates and chlorophytes. Our analysis identified several genes that are potentially involved in mitigating stress response (e.g., heat shock proteins pathways for mediating reactive oxygen species) and metabolic exchange (e.g., ion transporters). Finally, we show that S. muscatinei and other Symbiodinium strains are equipped with a high salt peridinin-chl-protein (HSPCP) gene previously identified only in free-living dinoflagellates. The addition of these transcriptomes to the cnidarian-symbiont molecular toolkit will aid in understanding how these vitally important symbiotic relationships are established and maintained across a variety of environmental conditions.
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Affiliation(s)
- Jason C Macrander
- Department of Biological Sciences, University of North Carolina, Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA.
| | - James L Dimond
- Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Road, Anacortes, WA 98221, USA
| | - Brian L Bingham
- Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Road, Anacortes, WA 98221, USA; Department of Environmental Sciences, Western Washington University, 516 High Street, Bellingham, WA 98225, USA
| | - Adam M Reitzel
- Department of Biological Sciences, University of North Carolina, Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA
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A unique EF-hand motif in mnemiopsin photoprotein from Mnemiopsis leidyi: implication for its low calcium sensitivity. Biochem Biophys Res Commun 2011; 413:164-70. [PMID: 21871870 DOI: 10.1016/j.bbrc.2011.08.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 08/04/2011] [Indexed: 11/21/2022]
Abstract
Up to now, all reported Ca(2+)-regulated photoproteins, except for mnemiopsin, have been cloned and expressed in Escherichia coli. In this study, the cDNA for an isotype of mnemiopsin, from the ctenophore Mnemiopsis leidyi, has been cloned, sequenced, and functionally expressed. The full length cDNA encoding mnemiopsin of M. leidyi was 624 bp open reading frame encoding a protein of 207 amino acid residues with calculated molecular mass of ∼24 kDa. The deduced amino acid sequence showed 90% and 84% identity to berovine (from ctenophore Beroe abyssicola) and bolinopsin 2 (from the ctenophore Bolinopsis infundibulum) respectively. In contrast to all known EF-hand in photoproteins, a unique EF-hand motif was found in mnemiopsin, in which a conserved glycine is substituted with glutamic acid. According to the results, the optimum pH was 9.0, time course of regeneration was 15 h and its Ca(2+) sensitivity was lower than aequorin. Results of pK(a) calculation for ionizable residues, motif scan and hydrophobic interactions of cavity aromatic residues of mnemiopsin in comparison with aequorin showed different patterns in these two photoproteins. In addition, experimental results are confirmed with the theoretical studies.
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Luan J, Zhang S, Liu Z, Fan C, Ji G, Li L. Characterization, evolution and tissue-specific expression of AmphiCalbin, a novel gene encoding EF-hand calcium-binding protein in amphioxus Branchiostoma belcheri. Acta Biochim Biophys Sin (Shanghai) 2007; 39:891-900. [PMID: 17989881 DOI: 10.1111/j.1745-7270.2007.00353.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
An amphioxus full-length cDNA, AmphiCalbin, encoding a novel EF-hand calcium-binding protein (EFCaBP), was isolated from the gut cDNA library of amphioxus Branchiostoma belcheri. It consists of 1321 bp with a 636 bp open reading frame encoding a protein of 211 amino acids with a molecular mass of approximately 24.5 kDa. The phylogenetic analysis offers two interesting inferences. First, AmphiCalbin clusters with a group of unnamed EFCaBPs that are differentiated from other identified EFCaBPs. Second, AmphiCalbin falls at the base of the vertebrate unnamed EFCaBPs clade, probably representing their prototype. This is also corroborated by the fact that AmphiCalbin has an exon-intron organization identical to that of vertebrate unnamed EFCaBP genes. Both tissue-section in situ hybridization and whole-mount in situ hybridization prove a tissue-specific expression pattern of AmphiCalbin, with high levels of expression in the digestive system and gonads. It is proposed that AmphiCalbin might play a role in the digestive system and gonads. These observations lay the foundation for further understanding of the function of the unnamed EFCaBPs.
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Affiliation(s)
- Jing Luan
- Department of Marine Biology, Ocean University of China, Qingdao 266003, China
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