1
|
Paek S, Kawai F, Venisetty N, Kim Y, Yeo HJ. Crystal structure of Campylobacter jejuni lipoprotein Cj1090c. Proteins 2023; 91:293-299. [PMID: 36201627 DOI: 10.1002/prot.26434] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 09/16/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022]
Abstract
In Gram-negative bacteria, lipopolysaccharide (LPS) is an essential component of the asymmetric outer membrane (OM). LptE is an OM lipoprotein that forms a complex with the β-barrel OM protein, LptD. Incorporation of LPS into the OM outer leaflet is essential for bacterial viability, and mediated by the LptD/E complex. The genome of Campylobacter jejuni, a major foodborne pathogen, contains over 20 putative lipoproteins including Cj1090c. Here, we report the crystal structure of Cj1090c at 2.4 Å resolution, revealing structural evidence for LptE in C. jejuni. The analysis of this crystal structure, along with the genomic context, allows us to propose the C. jejuni LPS transport system for the first time, and permits for discussion of the features of the LptD/E complex of C. jejuni.
Collapse
Affiliation(s)
- Seonghee Paek
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States
| | - Fumihiro Kawai
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States
| | - Nilamani Venisetty
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States
| | - Youngchang Kim
- Structural Biology Center, Argonne National Laboratory, Lemont, Illinois, United States
| | - Hye-Jeong Yeo
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States
| |
Collapse
|
2
|
Kim E, Kubota-Kawai H, Kawai F, Yokono M, Minagawa J. Regulation of light-harvesting systems in plants: Flexible conformation of light-harvesting complex II trimer depending on its binding site. Biophys J 2023; 122:242a. [PMID: 36783190 DOI: 10.1016/j.bpj.2022.11.1411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Eunchul Kim
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan
| | | | - Fumihiro Kawai
- Faculty of Science, Yamagata University, Yamagata, Japan
| | - Makio Yokono
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, Japan
| |
Collapse
|
3
|
Kim E, Kubota-Kawai H, Kawai F, Yokono M, Minagawa J. Conformation of Light-Harvesting Complex II Trimer Depends upon Its Binding Site. J Phys Chem B 2022; 126:5855-5865. [PMID: 35920883 DOI: 10.1021/acs.jpcb.2c04061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The light-harvesting complex II (LHCII) trimer in plants functions as a major antenna complex and a quencher to protect it from photooxidative damage. Theoretical studies on the structure of an LHCII trimer have demonstrated that excitation energy transfer between chlorophylls (Chls) in LHCII can be modulated by its exquisite conformational fluctuation. However, conformational changes depending on its binding location have not yet been investigated, even though reorganization of protein complexes occurs by physiological regulations. In this study, we investigated conformational differences in LHCII by comparing published structures of an identical LHCII trimer in the three different photosystem supercomplexes from the green alga Chlamydomonas reinhardtii. Our results revealed distinct differences in Chl configurations as well as polypeptide conformations of the LHCII trimers depending on its binding location. We propose that these configurational differences readily modulate the function of LHCII and possibly lead to a change in excitation-energy flow over the photosynthetic supercomplex.
Collapse
Affiliation(s)
- Eunchul Kim
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | | | - Fumihiro Kawai
- Faculty of Science, Yamagata University, Yamagata 990-8560, Japan
| | - Makio Yokono
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.,Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| |
Collapse
|
4
|
Kimura K, Kawai F, Kubota-Kawai H, Watanabe Y, Tomii K, Kojima R, Hirata K, Yamamori Y, Endo T, Tamura Y. Crystal structure of Tam41 cytidine diphosphate diacylglycerol synthase from a Firmicutes bacterium. J Biochem 2021; 171:429-441. [PMID: 34964897 DOI: 10.1093/jb/mvab154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Translocator assembly and maintenance 41 (Tam41) catalyzes the synthesis of cytidine diphosphate diacylglycerol (CDP-DAG), which is a high-energy intermediate phospholipid critical for generating cardiolipin in mitochondria. Although Tam41 is present almost exclusively in eukaryotic cells, a Firmicutes bacterium contains the gene encoding Tam41-type CDP-DAG synthase (FbTam41). FbTam41 converted phosphatidic acid (PA) to CDP-DAG using a ternary complex mechanism in vitro. Additionally, FbTam41 functionally substituted yeast Tam41 in vivo. These results demonstrate that Tam41-type CDP-DAG synthase functions in some prokaryotic cells. We determined the crystal structure of FbTam41 lacking the C-terminal 18 residues in the cytidine triphosphate (CTP)-Mg2+ bound form at a resolution of 2.6 Å. The crystal structure showed that FbTam41 contained a positively charged pocket that specifically accommodated CTP-Mg2+ and PA in close proximity. By using this structure, we constructed a model for the full-length structure of FbTam41 containing the last α-helix, which was missing in the crystal structure. Based on this model, we propose a molecular mechanism for CDP-DAG synthesis in bacterial cells and mitochondria.
Collapse
Affiliation(s)
- Keisuke Kimura
- Graduate School of Global Symbiotic Sciences, Yamagata University, Japan
| | | | | | | | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Rieko Kojima
- Faculty of Science, Yamagata University, Japan.,Toyama Prefectural Institute for Pharmaceutical Research, Toyama 939-0363, Japan
| | | | - Yu Yamamori
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
| | | |
Collapse
|
5
|
Iida T, Minagawa Y, Ueno H, Kawai F, Murata T, Iino R. Single-molecule analysis reveals rotational substeps and chemo-mechanical coupling scheme of Enterococcus hirae V 1-ATPase. J Biol Chem 2019; 294:17017-17030. [PMID: 31519751 PMCID: PMC6851342 DOI: 10.1074/jbc.ra119.008947] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/13/2019] [Indexed: 12/13/2022] Open
Abstract
V1-ATPase (V1), the catalytic domain of an ion-pumping V-ATPase, is a molecular motor that converts ATP hydrolysis-derived chemical energy into rotation. Here, using a gold nanoparticle probe, we directly observed rotation of V1 from the pathogen Enterococcus hirae (EhV1). We found that 120° steps in each ATP hydrolysis event are divided into 40 and 80° substeps. In the main pause before the 40° substep and at low ATP concentration ([ATP]), the time constant was inversely proportional to [ATP], indicating that ATP binds during the main pause with a rate constant of 1.0 × 107 m-1 s-1 At high [ATP], we observed two [ATP]-independent time constants (0.5 and 0.7 ms). One of two time constants was prolonged (144 ms) in a rotation driven by slowly hydrolyzable ATPγS, indicating that ATP is cleaved during the main pause. In another subpause before the 80° substep, we noted an [ATP]-independent time constant (2.5 ms). Furthermore, in an ATP-driven rotation of an arginine-finger mutant in the presence of ADP, -80 and -40° backward steps were observed. The time constants of the pauses before -80° backward and +40° recovery steps were inversely proportional to [ADP] and [ATP], respectively, indicating that ADP- and ATP-binding events trigger these steps. Assuming that backward steps are reverse reactions, we conclude that 40 and 80° substeps are triggered by ATP binding and ADP release, respectively, and that the remaining time constant in the main pause represents phosphate release. We propose a chemo-mechanical coupling scheme of EhV1, including substeps largely different from those of F1-ATPases.
Collapse
Affiliation(s)
- Tatsuya Iida
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan.,Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Yoshihiro Minagawa
- Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hiroshi Ueno
- Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Fumihiro Kawai
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Takeshi Murata
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.,Japan Science and Technology Agency (JST), PRESTO, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Ryota Iino
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan .,Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| |
Collapse
|
6
|
Kawai F, Nakamura A, Visootsat A, Iino R. Plasmid-Based One-Pot Saturation Mutagenesis and Robot-Based Automated Screening for Protein Engineering. ACS Omega 2018; 3:7715-7726. [PMID: 30221239 PMCID: PMC6130897 DOI: 10.1021/acsomega.8b00663] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/27/2018] [Indexed: 05/24/2023]
Abstract
We evaluated a method for protein engineering using plasmid-based one-pot saturation mutagenesis and robot-based automated screening. When the biases in nucleotides and amino acids were assessed for a loss-of-function point mutation in green fluorescent protein, the ratios of gain-of-function mutants were not significantly different from the expected values for the primers among the three different suppliers. However, deep sequencing analysis revealed that the ratios of nucleotides in the primers were highly biased among the suppliers. Biases for NNB were less severe than for NNN. We applied this method to screen a fusion protein of two chitinases, ChiA and ChiB (ChiAB). Three NNB codons as well as tyrosine and serine (X1YSX2X3) were inserted to modify the surface structure of ChiAB. We observed significant amino acid bias at the X3 position in water-soluble, active ChiAB-X1YSX2X3 mutants. Examination of the crystal structure of one active mutant, ChiAB-FYSFV, revealed that the X3 residue plays an important role in structure stabilization.
Collapse
Affiliation(s)
- Fumihiro Kawai
- Institute
for Molecular Science, National Institutes
of Natural Sciences, 5-1 Higashiyama Myodaijicho, Okazaki, Aichi 444-8787, Japan
| | - Akihiko Nakamura
- Institute
for Molecular Science, National Institutes
of Natural Sciences, 5-1 Higashiyama Myodaijicho, Okazaki, Aichi 444-8787, Japan
- The
Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Akasit Visootsat
- The
Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Ryota Iino
- Institute
for Molecular Science, National Institutes
of Natural Sciences, 5-1 Higashiyama Myodaijicho, Okazaki, Aichi 444-8787, Japan
- The
Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| |
Collapse
|
7
|
Kaneko M, Futamura Y, Tsukuda S, Kondoh Y, Sekine T, Hirano H, Fukano K, Ohashi H, Saso W, Morishita R, Matsunaga S, Kawai F, Ryo A, Park SY, Suzuki R, Aizaki H, Ohtani N, Sureau C, Wakita T, Osada H, Watashi K. Chemical array system, a platform to identify novel hepatitis B virus entry inhibitors targeting sodium taurocholate cotransporting polypeptide. Sci Rep 2018; 8:2769. [PMID: 29426822 PMCID: PMC5807303 DOI: 10.1038/s41598-018-20987-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 01/29/2018] [Indexed: 12/13/2022] Open
Abstract
Current anti-hepatitis B virus (HBV) agents including interferons and nucleos(t)ide analogs efficiently suppress HBV infection. However, as it is difficult to eliminate HBV from chronically infected liver, alternative anti-HBV agents targeting a new molecule are urgently needed. In this study, we applied a chemical array to high throughput screening of small molecules that interacted with sodium taurocholate cotransporting polypeptide (NTCP), an entry receptor for HBV. From approximately 30,000 compounds, we identified 74 candidates for NTCP interactants, and five out of these were shown to inhibit HBV infection in cell culture. One of such compound, NPD8716, a coumarin derivative, interacted with NTCP and inhibited HBV infection without causing cytotoxicity. Consistent with its NTCP interaction capacity, this compound was shown to block viral attachment to host hepatocytes. NPD8716 also prevented the infection with hepatitis D virus, but not hepatitis C virus, in agreement with NPD8716 specifically inhibiting NTCP-mediated infection. Analysis of derivative compounds showed that the anti-HBV activity of compounds was apparently correlated with the affinity to NTCP and the capacity to impair NTCP-mediated bile acid uptake. These results are the first to show that the chemical array technology represents a powerful platform to identify novel viral entry inhibitors.
Collapse
Affiliation(s)
- Manabu Kaneko
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,Department of Applied Biological Sciences, Tokyo University of Science, Noda, 278-8510, Japan
| | - Yushi Futamura
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science (CSRS), Wako, 351-0198, Japan
| | - Senko Tsukuda
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,Micro-signaling Regulation Technology Unit, RIKEN Center for Life Science Technologies (CLST), Wako, 351-0198, Japan
| | - Yasumitsu Kondoh
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science (CSRS), Wako, 351-0198, Japan
| | - Tomomi Sekine
- Bio-Active Compounds Discovery Research Unit, RIKEN CSRS, Wako, 351-0198, Japan
| | - Hiroyuki Hirano
- Chemical Resource Development Research Unit, RIKEN CSRS, Wako, 351-0198, Japan
| | - Kento Fukano
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,Department of Analytical Biochemistry, Meiji Pharmaceutical University, Kiyose, 204-8588, Japan
| | - Hirofumi Ohashi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,Department of Applied Biological Sciences, Tokyo University of Science, Noda, 278-8510, Japan
| | - Wakana Saso
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.,The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Ryo Morishita
- CellFree Sciences Co., Ltd, Matsuyama, 790-8577, Japan
| | - Satoko Matsunaga
- Department of Microbiology, Yokohama City University Graduate School of Medicine, Yokohama, 236-0027, Japan
| | - Fumihiro Kawai
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, 230-0045, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University Graduate School of Medicine, Yokohama, 236-0027, Japan
| | - Sam-Yong Park
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, 230-0045, Japan
| | - Ryosuke Suzuki
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Hideki Aizaki
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Naoko Ohtani
- Department of Applied Biological Sciences, Tokyo University of Science, Noda, 278-8510, Japan
| | - Camille Sureau
- Laboratoire de Virologie Moléculaire, Institut National de la Transfusion Sanguine, INSERM U1134, Paris, 75015, France
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Hiroyuki Osada
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science (CSRS), Wako, 351-0198, Japan.
| | - Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan. .,Department of Applied Biological Sciences, Tokyo University of Science, Noda, 278-8510, Japan. .,CREST, JST, Saitama, 332-0012, Japan.
| |
Collapse
|
8
|
Iida T, Minagawa Y, Ueno H, Kawai F, Murata T, Iino R. Chemo-Mechanical Coupling of Rotary Molecular Motor Enterococcus Hirae V1-ATPase as Revealed by Single-Molecule Analysis. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
9
|
Shimura S, Watashi K, Fukano K, Peel M, Sluder A, Kawai F, Iwamoto M, Tsukuda S, Takeuchi JS, Miyake T, Sugiyama M, Ogasawara Y, Park SY, Tanaka Y, Kusuhara H, Mizokami M, Sureau C, Wakita T. Cyclosporin derivatives inhibit hepatitis B virus entry without interfering with NTCP transporter activity. J Hepatol 2017; 66:685-692. [PMID: 27890789 PMCID: PMC7172969 DOI: 10.1016/j.jhep.2016.11.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 10/25/2016] [Accepted: 11/14/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS The sodium taurocholate co-transporting polypeptide (NTCP) is the main target of most hepatitis B virus (HBV) specific entry inhibitors. Unfortunately, these agents also block NTCP transport of bile acids into hepatocytes, and thus have the potential to cause adverse effects. We aimed to identify small molecules that inhibit HBV entry while maintaining NTCP transporter function. METHODS We characterized a series of cyclosporine (CsA) derivatives for their anti-HBV activity and NTCP binding specificity using HepG2 cells overexpressing NTCP and primary human hepatocytes. The four most potent derivatives were tested for their capacity to prevent HBV entry, but maintain NTCP transporter function. Their antiviral activity against different HBV genotypes was analysed. RESULTS We identified several CsA derivatives that inhibited HBV infection with a sub-micromolar IC50. Among them, SCY446 and SCY450 showed low activity against calcineurin (CN) and cyclophilins (CyPs), two major CsA cellular targets. This suggested that instead, these compounds interacted directly with NTCP to inhibit viral attachment to host cells, and have no immunosuppressive function. Importantly, we found that SCY450 and SCY995 did not impair the NTCP-dependent uptake of bile acids, and inhibited multiple HBV genotypes including a clinically relevant nucleoside analog-resistant HBV isolate. CONCLUSIONS This is the first example of small molecule selective inhibition of HBV entry with no decrease in NTCP transporter activity. It suggests that the anti-HBV activity can be functionally separated from bile acid transport. These broadly active anti-HBV molecules are potential candidates for developing new drugs with fewer adverse effects. LAY SUMMARY In this study, we identified new compounds that selectively inhibited hepatitis B virus (HBV) entry, and did not impair bile acid uptake. Our evidence offers a new strategy for developing anti-HBV drugs with fewer side effects.
Collapse
Affiliation(s)
- Satomi Shimura
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; SCYNEXIS, Inc., Durham, NC 27713, USA
| | - Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; Department of Applied Biological Science, Tokyo University of Sciences, Noda 278-8510, Japan; CREST, Japan Science and Technology Agency (J.S.T.), Saitama 332-0012, Japan.
| | - Kento Fukano
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; Department of Analytical Biochemistry, Meiji Pharmaceutical University, Kiyose 204-8588, Japan
| | | | | | - Fumihiro Kawai
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama 230-0045, Japan
| | - Masashi Iwamoto
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; Department of Applied Biological Science, Tokyo University of Sciences, Noda 278-8510, Japan
| | - Senko Tsukuda
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan; Micro-signaling Regulation Technology Unit, RIKEN Center for Life Science Technologies, Wako 351-0198, Japan
| | - Junko S Takeuchi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Takeshi Miyake
- The University of Tokyo, Graduate School of Pharmaceutical Sciences, Tokyo 113-0033, Japan
| | - Masaya Sugiyama
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
| | - Yuki Ogasawara
- Department of Analytical Biochemistry, Meiji Pharmaceutical University, Kiyose 204-8588, Japan
| | - Sam-Yong Park
- Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama 230-0045, Japan
| | - Yasuhito Tanaka
- Department of Virology and Liver Unit, Nagoya City University Graduate School of Medicinal Sciences, Nagoya 467-8601, Japan
| | - Hiroyuki Kusuhara
- The University of Tokyo, Graduate School of Pharmaceutical Sciences, Tokyo 113-0033, Japan
| | - Masashi Mizokami
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa 272-8516, Japan
| | - Camille Sureau
- Laboratoire de Virologie Moléculaire, Institut National de la Transfusion Sanguine (INTS), Paris, France
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| |
Collapse
|
10
|
Ohki M, Sugiyama K, Kawai F, Matsunaga S, Iseki M, Park SY. Structural basis for photoactivation of a light-regulated adenylate cyclase from the photosynthetic cyanobacterium Oscillatoria acuminata. Acta Crystallogr A Found Adv 2016. [DOI: 10.1107/s2053273316096194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
11
|
Paek S, Kawai F, Choi KJ, Yeo HJ. Crystal structure of the Campylobacter jejuni Cj0090 protein reveals a novel variant of the immunoglobulin fold among bacterial lipoproteins. Proteins 2012; 80:2804-9. [PMID: 22987763 DOI: 10.1002/prot.24182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 08/28/2012] [Accepted: 09/03/2012] [Indexed: 11/09/2022]
Abstract
Bacterial lipoproteins play an important role in bacterial pathogenesis and physiology. The genome of Campylobacter jejuni, a major foodborn pathogen, is predicted to contain over 20 lipoproteins. However, the functions of the majority of C. jejuni lipoproteins remain unknown. The Cj0090 protein is encoded by a lipoprotein operon composed of cj0089, cj0090, and cj0091. Here, we report the crystal structure of Cj0090 at 1.9 Å resolution, revealing a novel variant of the immunoglobulin fold with β-sandwich architecture. The structure suggests that Cj0090 may be involved in protein-protein interactions, consistent with a possible role for bacterial lipoproteins.
Collapse
Affiliation(s)
- Seonghee Paek
- Department of Biology and Biochemistry, University of Houston, TX 77204, USA
| | | | | | | |
Collapse
|
12
|
Yoshida H, Kawai F, Obayashi E, Akashi S, Roper DI, Tame JRH, Park SY. Crystal structures of penicillin-binding protein 3 (PBP3) from methicillin-resistant Staphylococcus aureus in the apo and cefotaxime-bound forms. J Mol Biol 2012; 423:351-64. [PMID: 22846910 DOI: 10.1016/j.jmb.2012.07.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/04/2012] [Accepted: 07/16/2012] [Indexed: 10/28/2022]
Abstract
Staphylococcus aureus is a widespread Gram-positive opportunistic pathogen, and a methicillin-resistant form (MRSA) is particularly difficult to treat clinically. We have solved two crystal structures of penicillin-binding protein (PBP) 3 (PBP3) from MRSA, the apo form and a complex with the β-lactam antibiotic cefotaxime, and used electrospray mass spectrometry to measure its sensitivity to a variety of penicillin derivatives. PBP3 is a class B PBP, possessing an N-terminal non-penicillin-binding domain, sometimes called a dimerization domain, and a C-terminal transpeptidase domain. The model shows a different orientation of its two domains compared to earlier models of other class B PBPs and a novel, larger N-domain. Consistent with the nomenclature of "dimerization domain", the N-terminal region forms an apparently tight interaction with a neighboring molecule related by a 2-fold symmetry axis in the crystal structure. This dimer form is predicted to be highly stable in solution by the PISA server, but mass spectrometry and analytical ultracentrifugation provide unequivocal evidence that the protein is a monomer in solution.
Collapse
Affiliation(s)
- Hisashi Yoshida
- Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan
| | | | | | | | | | | | | |
Collapse
|
13
|
Kawai F, Paek S, Choi KJ, Prouty M, Kanipes MI, Guerry P, Yeo HJ. Crystal structure of JlpA, a surface-exposed lipoprotein adhesin of Campylobacter jejuni. J Struct Biol 2012; 177:583-8. [PMID: 22245776 DOI: 10.1016/j.jsb.2012.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/31/2011] [Accepted: 01/02/2012] [Indexed: 11/15/2022]
Abstract
The Campylobacter jejuni JlpA protein is a surface-exposed lipoprotein that was discovered as an adhesin promoting interaction with host epithelium cells, an early critical step in the pathogenesis of C. jejuni disease. Increasing evidence ascertained that JlpA is antigenic, indicating a role of JlpA in immune response during the infectious process. Here, we report the crystal structure of JlpA at 2.7Å resolution, revealing a catcher's mitt shaped unclosed half β-barrel. Although the apparent architecture of JlpA is somewhat reminiscent of other bacterial lipoproteins such as LolB, the topology of JlpA is unique among the bacterial surface proteins reported to date and therefore JlpA represents a novel bacterial cell surface lipoprotein. The concave face of the structure results in an unusually large hydrophobic basin with a localized acidic pocket, suggesting a possibility that JlpA may accommodate multiple ligands. Therefore, the structure provides framework for determining the molecular function of JlpA and new strategies for the rational design of small molecule inhibitors efficiently targeting JlpA.
Collapse
Affiliation(s)
- Fumihiro Kawai
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | | | | | | | | | | | | |
Collapse
|
14
|
|
15
|
Kawai F, Grass S, Kim Y, Choi KJ, St Geme JW, Yeo HJ. Structural insights into the glycosyltransferase activity of the Actinobacillus pleuropneumoniae HMW1C-like protein. J Biol Chem 2011; 286:38546-38557. [PMID: 21908603 DOI: 10.1074/jbc.m111.237602] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Glycosylation of proteins is a fundamental process that influences protein function. The Haemophilus influenzae HMW1 adhesin is an N-linked glycoprotein that mediates adherence to respiratory epithelium, an essential early step in the pathogenesis of H. influenzae disease. HMW1 is glycosylated by HMW1C, a novel glycosyltransferase in the GT41 family that creates N-glycosidic linkages with glucose and galactose at asparagine residues and di-glucose linkages at sites of glucose modification. Here we report the crystal structure of Actinobacillus pleuropneumoniae HMW1C (ApHMW1C), a functional homolog of HMW1C. The structure of ApHMW1C contains an N-terminal all α-domain (AAD) fold and a C-terminal GT-B fold with two Rossmann-like domains and lacks the tetratricopeptide repeat fold characteristic of the GT41 family. The GT-B fold harbors the binding site for UDP-hexose, and the interface of the AAD fold and the GT-B fold forms a unique groove with potential to accommodate the acceptor protein. Structure-based functional analyses demonstrated that the HMW1C protein shares the same structure as ApHMW1C and provided insights into the unique bi-functional activity of HMW1C and ApHMW1C, suggesting an explanation for the similarities and differences of the HMW1C-like proteins compared with other GT41 family members.
Collapse
Affiliation(s)
- Fumihiro Kawai
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204
| | - Susan Grass
- Departments of Pediatrics and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Youngchang Kim
- Structural Biology Center, Argonne National Laboratory, Argonne, Illinois 60439
| | - Kyoung-Jae Choi
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204
| | - Joseph W St Geme
- Departments of Pediatrics and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Hye-Jeong Yeo
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204.
| |
Collapse
|
16
|
Kawai F, Grass S, Kim Y, Choi KJ, St Geme III JW, Yeo HJ. Crystal structure of Actinobacillus pleuropneumoniaeHMW1C glycosyltransferase. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311087940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
17
|
Kawai F, Shibata M, Yokoyama S, Maeda S, Tada K, Hayashi S. Biodegradability of scott-gelead photodegradable polyethylene and polyethylene wax by microorganisms. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.19991440108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
18
|
|
19
|
Tajima N, Kawai F, Park SY, Tame JR. A Novel Intein-Like Autoproteolytic Mechanism in Autotransporter Proteins. J Mol Biol 2010; 402:645-56. [DOI: 10.1016/j.jmb.2010.06.068] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 06/24/2010] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
|
20
|
Yoon YH, Kawai F, Sugiyama K, Park SY, Nihira T, Choi SU, Hwang YI. Crystallization and preliminary crystallographic studies of the butyrolactone autoregulator receptor protein (BarA) from Streptomyces virginiae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:662-4. [PMID: 20516594 PMCID: PMC2882764 DOI: 10.1107/s1744309110009930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/17/2010] [Indexed: 11/10/2022]
Abstract
The Streptomyces butyrolactone autoregulator receptor protein (BarA) is a DNA-binding protein that regulates the biosynthesis of the antibiotic virginiamycin. In this study, BarA from S. virginiae was overexpressed in Escherichia coli, purified and crystallized. Crystals of purified protein have been grown that diffracted to beyond 3.0 A resolution at 100 K using synchrotron radiation. The protein crystals belonged to the hexagonal space group P6(5)22, with unit-cell parameters a = b = 128.0, c = 286.2 A. With four molecules per asymmetric unit, the crystal volume per unit protein mass (V(M)) was 3.2 A(3) Da(-1) and the solvent content was 62%.
Collapse
Affiliation(s)
- Young-Ho Yoon
- Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Fumihiro Kawai
- Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Kanako Sugiyama
- Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Sam-Yong Park
- Protein Design Laboratory, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Takuya Nihira
- International Center for Biotechnology, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Sun-Uk Choi
- Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701, Republic of Korea
| | - Yong-Il Hwang
- Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701, Republic of Korea
| |
Collapse
|
21
|
Kawai F, Clarke TB, Roper DI, Han GJ, Hwang KY, Unzai S, Obayashi E, Park SY, Tame JR. Crystal Structures of Penicillin-Binding Proteins 4 and 5 from Haemophilus influenzae. J Mol Biol 2010; 396:634-45. [DOI: 10.1016/j.jmb.2009.11.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 11/20/2009] [Accepted: 11/22/2009] [Indexed: 10/20/2022]
|
22
|
Clarke TB, Kawai F, Park SY, Tame JRH, Dowson CG, Roper DI. Mutational analysis of the substrate specificity of Escherichia coli penicillin binding protein 4. Biochemistry 2009; 48:2675-83. [PMID: 19209901 DOI: 10.1021/bi801993x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Escherichia coli PBP4 is the archetypal class C, low molecular mass penicillin binding protein (LMM-PBP) and possesses both dd-carboxypeptidase and dd-endopeptidase activity. In contrast to other classes of PBP, class C LMM-PBPs show high dd-carboxypeptidase activity and rapidly hydrolyze synthetic fragments of peptidoglycan. The recently solved X-ray crystal structures of three class C LMM-PBPs (E. coli PBP4, Bacillus subtilis PBP4a, and Actinomadura R39 dd-peptidase) have identified several residues that form a pocket in the active site unique to this class of PBP. The X-ray cocrystal structure of the Actinomadura R39 DD-peptidase with a cephalosporin bearing a peptidoglycan-mimetic side chain showed that residues of this pocket interact with the third position meso-2,6-diaminopimelic acid residue of the peptidoglycan stem peptide. Equivalent residues of E. coli PBP4 (Asp155, Phe160, Arg361, and Gln422) were mutated, and the effect on both DD-carboxypeptidase and DD-endopeptidase activities was determined. Using N-acetylmuramyl-L-alanyl-gamma-D-glutamyl-meso-2,6-diaminopimelyl-D-alanyl-D-alanine as substrate, mutation of Asp155, Phe160, Arg361, and Gln422 to alanine reduced k(cat)/K(m) by 12.7-, 1.9-, 24.5-, and 13.8-fold, respectively. None of the k(cat) values deviated significantly from wild-type PBP4. PBP4 DD-endopeptidase activity was also affected, with substitution of Asp155, Arg361, and Gln422 reducing specific activity by 22%, 56%, and 40%, respectively. This provides the first direct demonstration of the importance of residues forming a subsite to accommodate meso-2,6-diaminopimelic acid in both the DD-carboxypeptidase and DD-endopeptidase activities of a class C LMM-PBP.
Collapse
Affiliation(s)
- Thomas B Clarke
- Department of Biological Sciences, University of Warwick, Coventry, UK.
| | | | | | | | | | | |
Collapse
|
23
|
Kawai F, Unzai S, Tame R, Park SY, Sato M, Inaka K, Tanaka H, Nakagawa A. Expression, purification and crystallization of LMW-PBP 4 and 5 from Haemophilus influenzae. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308088958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
24
|
Tomita A, Sato T, Ichiyanagi K, Nozawa S, Ichikawa H, Chollet M, Kawai F, Park SY, Koshihara S, Adachi S. Slow ligand migration dynamics in carbonmonoxy myoglobin at cryogenic temperature. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308088545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
25
|
Akazaki H, Kawai F, Chida H, Matsumoto Y, Hirayama M, Hoshikawa K, Unzai S, Hakamata W, Nishio T, Park SY, Oku T. Cloning, expression and purification of cytochrome c(6) from the brown alga Hizikia fusiformis and complete X-ray diffraction analysis of the structure. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:674-80. [PMID: 18678931 PMCID: PMC2494970 DOI: 10.1107/s1744309108017752] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Accepted: 06/11/2008] [Indexed: 11/10/2022]
Abstract
The primary sequence of cytochrome c(6) from the brown alga Hizikia fusiformis has been determined by cDNA cloning and the crystal structure has been solved at 1.6 A resolution. The crystal belonged to the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 84.58, c = 232.91 A and six molecules per asymmetric unit. The genome code, amino-acid sequence and crystal structure of H. fusiformis cytochrome c(6) were most similar to those of red algal cytochrome c(6). These results support the hypothesis that brown algae acquired their chloroplasts via secondary endosymbiosis involving a red algal endosymbiont and a eukaryote host.
Collapse
Affiliation(s)
- Hideharu Akazaki
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Fumihiro Kawai
- Protein Design Laboratory, Graduate School of Integrated Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Hirotaka Chida
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Yuichirou Matsumoto
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Mao Hirayama
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Ken Hoshikawa
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Satoru Unzai
- Protein Design Laboratory, Graduate School of Integrated Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Wataru Hakamata
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Toshiyuki Nishio
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Sam-Yong Park
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | - Tadatake Oku
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| |
Collapse
|
26
|
Addy C, Ohara M, Kawai F, Kidera A, Ikeguchi M, Fuchigami S, Osawa M, Shimada I, Park SY, Tame JRH, Heddle JG. Nickel binding to NikA: an additional binding site reconciles spectroscopy, calorimetry and crystallography. Acta Crystallogr D Biol Crystallogr 2007; 63:221-9. [PMID: 17242515 DOI: 10.1107/s0907444906048712] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 11/15/2006] [Indexed: 11/11/2022]
Abstract
Intracellular nickel is required by Escherichia coli as a cofactor for a number of enzymes and is necessary for anaerobic respiration. However, high concentrations of nickel are toxic, so both import and export systems have evolved to control the cellular level of the metal. The nik operon in E. coli encodes a nickel-uptake system that includes the periplasmic nickel-binding protein NikA. The crystal structures of wild-type NikA both bound to nickel and in the apo form have been solved previously. The liganded structure appeared to show an unusual interaction between the nickel and the protein in which no direct bonds are formed. The highly unusual nickel coordination suggested by the crystal structure contrasted strongly with earlier X-ray spectroscopic studies. The known nickel-binding site has been probed by extensive mutagenesis and isothermal titration calorimetry and it has been found that even large numbers of disruptive mutations appear to have little effect on the nickel affinity. The crystal structure of a binding-site mutant with nickel bound has been solved and it is found that nickel is bound to two histidine residues at a position distant from the previously characterized binding site. This novel site immediately resolves the conflict between the crystal structures and other biophysical analyses. The physiological relevance of the two binding sites is discussed.
Collapse
Affiliation(s)
- Christine Addy
- Graduate School of Integrated Science, Yokohama City University, Tsurumi, Suehiro 1-7-29, Yokohama 230-0045, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Chida H, Yokoyama T, Kawai F, Nakazawa A, Akazaki H, Takayama Y, Hirano T, Suruga K, Satoh T, Yamada S, Kawachi R, Unzai S, Nishio T, Park SY, Oku T. Crystal structure of oxidized cytochromec6AfromArabidopsis thaliana. FEBS Lett 2006; 580:3763-8. [PMID: 16777100 DOI: 10.1016/j.febslet.2006.05.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 05/12/2006] [Accepted: 05/27/2006] [Indexed: 10/24/2022]
Abstract
Compared with algal and cyanobacterial cytochrome c(6), cytochrome c(6A) from higher plants contains an additional loop of 12 amino acid residues. We have determined the first crystal structure of cytochrome c(6A) from Arabidopsis thaliana at 1.5 Angstrom resolution in order to help elucidate its function. The overall structure of cytochrome c(6A) follows the topology of class I c-type cytochromes in which the heme prosthetic group covalently binds to Cys16 and Cys19, and the iron has octahedral coordination with His20 and Met60 as the axial ligands. Two cysteine residues (Cys67 and Cys73) within the characteristic 12 amino acids loop form a disulfide bond, contributing to the structural stability of cytochrome c(6A). Our model provides a chemical basis for the known low redox potential of cytochrome c(6A) which makes it an unsuitable electron carrier between cytochrome b(6)f and PSI.
Collapse
Affiliation(s)
- Hirotaka Chida
- Bio-organic Chemistry Laboratory, Graduate School of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa-shi, Kanagawa 252-8510, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Izumi A, Otto BR, Kawai F, Heddle J, Park SY, Tame JRH. Crystal structure of heme binding enolase P46 from Bacteroides fragillis. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305092718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
29
|
Ohta T, Tani A, Kimbara K, Kawai F. A novel nicotinoprotein aldehyde dehydrogenase involved in polyethylene glycol degradation. Appl Microbiol Biotechnol 2005; 68:639-46. [PMID: 15726348 DOI: 10.1007/s00253-005-1936-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 01/30/2005] [Accepted: 02/03/2005] [Indexed: 12/01/2022]
Abstract
A gene (pegC) encoding aldehyde dehydrogenase (ALDH) was located 3.4 kb upstream of a gene encoding polyethylene glycol (PEG) dehydrogenase (pegA) in Sphingomonas macrogoltabidus strain 103. ALDH was expressed in Escherichia coli and purified on a Ni-nitrilotriacetic acid agarose column. The recombinant enzyme was a homotetramer consisting of four 46.1-kDa subunits. The alignment of the putative amino acid sequence of the cloned enzyme showed high similarity with a group of NAD(P)-dependent ALDHs (identity 36-52%); NAD-binding domains (Rossmann fold and four glycine residues) and catalytic residues (Glu225 and Cys259) were well conserved. The cofactor, which was extracted from the purified enzyme, was tightly bound to the enzyme and identified as NADP. The enzyme contained 0.94 mol NADP per subunit. The enzyme was activated by Ca(2+), but by no other metals; no metal (Zn, Fe, Mg, or Mn) was detected in the purified recombinant enzyme. Activity was inhibited by p-chloromercuric benzoate, and heavy metals such as Hg, Cu, Pb and Cd, indicating that a cysteine residue is involved in the activity. Enzyme activity was independent of N,N-dimethyl-p-nitrosoaniline as an electron acceptor. Trans-4-(N,N-dimethylamino)-cinnamaldehyde was not oxidized as a substrate, but the compound worked as an inhibitor for the enzyme, as did pyrazole. The enzyme acted on n-aldehydes C(2)-C(14)) and PEG-aldehydes. Thus the enzyme was concluded to be a novel Ca(2+)-activating nicotinoprotein (NADP-containing) PEG-aldehyde dehydrogenase involved in the degradation of PEG in S. macrogoltabidus strain 103.
Collapse
Affiliation(s)
- T Ohta
- Research Institute for Bioresources, Okayama University, Kurashiki, Japan
| | | | | | | |
Collapse
|
30
|
Narusuye K, Kawai F, Matsuzaki K, Miyachi E. Linalool suppresses voltage-gated currents in sensory neurons and cerebellar Purkinje cells. J Neural Transm (Vienna) 2004; 112:193-203. [PMID: 15365786 DOI: 10.1007/s00702-004-0187-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Accepted: 06/10/2004] [Indexed: 10/26/2022]
Abstract
Linalool is a major component of essential oils and possesses various biological effects in sensory or central nervous systems. To investigate the pharmacological and biophysical effects of linalool on voltage-gated currents in sensory neurons, we used the whole-cell patch clamp and the Ca(2+) imaging techniques. Under the voltage clamp, membrane depolarization generated time- and voltage-dependent current responses in newt olfactory receptor cells (ORCs). Linalool significantly and reversibly suppressed the voltage-gated currents in ORCs. The dose-suppression relation of linalool for the voltage-gated Na(+) current could be fitted by the Hill equation with a half-blocking concentration of 0.56 mM and a Hill coefficient of 1.2. To test whether linalool suppresses voltage-gated currents in ORCs specifically or suppresses currents in other neurons generally, we next examined the effects of linalool on voltage-gated currents in newt retinal neurons and rat cerebellar Purkinje cells. Linalool suppressed the voltage-gated currents not only in retinal horizontal cells and ganglion cells but also in Purkinje cells. Furthermore, bath application of linalool inhibited the KCl-induced [Ca(2+)](i) response of ORCs, suggesting that linalool suppresses Ca(2+) currents in ORCs. These results suggest that linalool non-selectively suppresses the voltage-gated currents in newt sensory neurons and rat cerebellar Purkinje cells.
Collapse
Affiliation(s)
- K Narusuye
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
| | | | | | | |
Collapse
|
31
|
Tani A, Zhang D, Duine JA, Kawai F. Treatment of the yeast Rhodotorula glutinis with AlCl3 leads to adaptive acquirement of heritable aluminum resistance. Appl Microbiol Biotechnol 2004; 65:344-8. [PMID: 14740194 DOI: 10.1007/s00253-003-1546-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 12/06/2003] [Accepted: 12/12/2003] [Indexed: 11/30/2022]
Abstract
When aluminum (Al) was added to a culture, growth of Rhodotorula glutinis IFO1125 was temporarily arrested, showing longer lag phases, depending on the Al concentrations (50-300 microM) added, but the growth rates were not affected at all. Resistant strains obtained by one round of plate treatment containing Al reverted the resistance level to the wild-type level when cultivated without Al. Repeated Al treatments, however, induced heritable and stable Al resistance, the level of which was increased up to 4,000 microM by stepwise increments in Al concentrations. Thus, the heritable Al resistance adaptively acquired was due neither to adaptation nor to mutation, but to a mechanism which has yet to be studied. Heritable Al resistance seemed to release the Al inhibition of magnesium uptake.
Collapse
Affiliation(s)
- A Tani
- Research Institute for Bioresources, Okayama University, 2-20-1 Chuo, Kurashiki, 710-0046, Okayama, Japan
| | | | | | | |
Collapse
|
32
|
Abstract
Odorants are known to suppress voltage-gated channels not only in olfactory receptor cells but also in neurons of outside of the olfactory system. Here we found that odorants suppress glutamate-gated channels in newt retinal neurons using the Ca(2+) imaging technique. Bath application of 100 microM glutamate rose [Ca(2+)](i) under application of the voltage-gated Ca(2+) channel blocker. Thus, [Ca(2+)](i) rises in the neurons were most likely attributable to Ca(2+) influx via Ca(2+)-permeable glutamate-gated channels rather than voltage-gated Ca(2+) channels. A similar increase of [Ca(2+)](i) was observed by application of 100 microM NMDA and 50 microM kainate, suggesting that both NMDA and AMPA/kainate receptors were expressed in newt retinal neurons. Application of odorants, 1 mM amyl acetate and acetophenone, reversibly reduced [Ca(2+)](i) increased by glutamate, NMDA and kainate. This suggests that odorants can suppress not only voltage-gated channels but also ligand-gated channels such as NMDA and AMPA/kainate receptors.
Collapse
Affiliation(s)
- M Ohkuma
- Department of Physiology, Fujita Health University, Toyoake, Aichi, Japan.
| | | | | |
Collapse
|
33
|
Abstract
This paper summarizes studies on microbial degradation of polyethers. Polyethers are aerobically metabolized through common mechanisms (oxidation of terminal alcohol groups followed by terminal ether cleavage), well-characterized examples being found with polyethylene glycol (PEG). First the polymer is oxidized to carboxylated PEG by alcohol and aldehyde dehydrogenases and then the terminal ether bond is cleaved to yield the depolymerized PEG by one glycol unit. Most probably PEG is anaerobically metabolized through one step which is catalyzed by PEG acetaldehyde lyase, analogous to diol dehydratase. Whether aerobically or anaerobically, the free OH group is necessary for metabolization of PEG. PEG with a molecular weight of up to 20,000 was metabolized either in the periplasmic space (Pseudomonas stutzeri and sphingomonads) or in the cytoplasm (anaerobic bacteria), which suggests the transport of large PEG through the outer and inner membranes of Gram-negative bacterial cells. Membrane-bound PEG dehydrogenase (PEG-DH) with high activity towards PEG 6,000 and 20,000 was purified from PEG-utilizing sphingomonads. Sequencing of PEG-DH revealed that the enzyme belongs to the group of GMC flavoproteins, FAD being the cofactor for the enzyme. On the other hand, alcohol dehydrogenases purified from other bacteria that cannot grow on PEG oxidized PEG. Cytoplasmic NAD-dependent alcohol dehydrogenases with high specificity towards ether-alcohol compound, either crude or purified, showed appreciable activity towards PEG 400 or 600. Liver alcohol dehydrogenase (equine) also oxidized PEG homologs, which might cause fatal toxic syndrome in vivo by carboxylating PEG together with aldehyde dehydrogenase when PEG was absorbed. An ether bond-cleaving enzyme was detected in PEG-utilizing bacteria and purified as diglycolic acid (DGA) dehydrogenase from a PEG-utilizing consortium. The enzyme oxidized glycolic acid, glyoxylic acid, as well as PEG-carboxylic acid and DGA. Similarly, dehydrogenation on polypropylene glycol (PPG) and polytetramethylene glycol (PTMG) was suggested with cell-free extracts of PPG and PTMG-utilizing bacteria, respectively. PPG commercially available is atactic and includes many structural (primary and secondary alcohol groups) and optical (derived from pendant methyl groups on the carbon backbone) isomers. Whether PPG dehydrogenase (PPG-DH) has wide stereo- and enantioselective substrate specificity towards PPG isomers or not must await further purification. Preliminary research on PPG-DH revealed that the enzyme was inducibly formed by PPG in the periplasmic, membrane and cytoplasm fractions of a PPG-utilizing bacterium Stenotrophomonas maltophilia. This finding indicated the intracellular metabolism of PPG is the same as that of PEG. Besides metabolization of polyethers, a biological Fenton mechanism was proposed for degradation of PEG, which was caused by extracellular oxidants produced by a brown-rot fungus in the presence of a reductant and Fe3+, although the metabolism of fragmented PEG has not yet been well elucidated.
Collapse
Affiliation(s)
- F Kawai
- Research Institute for Bioresources, Okayama University, Kurashiki, Japan.
| |
Collapse
|
34
|
Sugimoto M, Tanabe M, Hataya M, Enokibara S, Duine JA, Kawai F. The first step in polyethylene glycol degradation by sphingomonads proceeds via a flavoprotein alcohol dehydrogenase containing flavin adenine dinucleotide. J Bacteriol 2001; 183:6694-8. [PMID: 11673442 PMCID: PMC95503 DOI: 10.1128/jb.183.22.6694-6698.2001] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several Sphingomonas spp. utilize polyethylene glycols (PEGs) as a sole carbon and energy source, oxidative PEG degradation being initiated by a dye-linked dehydrogenase (PEG-DH) that oxidizes the terminal alcohol groups of the polymer chain. Purification and characterization of PEG-DH from Sphingomonas terrae revealed that the enzyme is membrane bound. The gene encoding this enzyme (pegA) was cloned, sequenced, and expressed in Escherichia coli. The purified recombinant enzyme was vulnerable to aggregation and inactivation, but this could be prevented by addition of detergent. It is as a homodimeric protein with a subunit molecular mass of 58.8 kDa, each subunit containing 1 noncovalently bound flavin adenine dinucleotide but not Fe or Zn. PEG-DH recognizes a broad variety of primary aliphatic and aromatic alcohols as substrates. Comparison with known sequences revealed that PEG-DH belongs to the group of glucose-methanol-choline (GMC) flavoprotein oxidoreductases and that it is a novel type of flavoprotein alcohol dehydrogenase related (percent identical amino acids) to other, so far uncharacterized bacterial, membrane-bound, dye-linked dehydrogenases: alcohol dehydrogenase from Pseudomonas oleovorans (46%); choline dehydrogenase from E. coli (40%); L-sorbose dehydrogenase from Gluconobacter oxydans (38%); and 4-nitrobenzyl alcohol dehydrogenase from a Pseudomonas species (35%).
Collapse
Affiliation(s)
- M Sugimoto
- Research Institute for Bioresources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | | | | | | | | | | |
Collapse
|
35
|
Kawai F, Miyachi E. Enhancement by T-type Ca2+ currents of odor sensitivity in olfactory receptor cells. J Neurosci 2001; 21:RC144. [PMID: 11319242 PMCID: PMC6762504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Mechanisms underlying action potential initiation in olfactory receptor cells (ORCs) during odor stimulation were investigated using conventional and dynamic patch-clamp recording techniques. Under current-clamp conditions, action potentials generated by a least effective odor-induced depolarization were almost completely blocked by 0.1 mm Ni(2+), a T-type Ca(2+) channel blocker, but not by 0.1 mm Cd(2+), a high voltage-activated Ca(2+) channel blocker. Under voltage-clamp conditions, depolarizing voltage steps induced a fast transient inward current, which consisted of Na(+) (I(Na)) and T-type Ca(2+) (I(Ca,T)) currents. The amplitude of I(Ca,T) was approximately one-fourth of that of I(Na) (0.23 +/- 0.03, mean +/- SEM). Because both I(Na) and I(Ca,T) are known to show rapid inactivation, we examined how much I(Na) and I(Ca,T) are activated during the gradually depolarizing initial phase of receptor potentials. The ratio of I(Ca,T)/I(Na) during a ramp depolarization at the slope of 0.5 mV/msec was 0.56 +/- 0.03. Using the dynamic patch-clamp recording technique, we also recorded I(Ca,T) and I(Na) during the generation of odor-induced action potentials. This ratio of I(Ca,T)/I(Na) was 0.54 +/- 0.04. These ratios were more than twice as large as that (0.23) obtained from the experiment using voltage steps, suggesting that I(Ca,T) carries significant amount of current to generate the action potentials. We conclude that I(Ca,T) contributes to enhance odor sensitivity by lowering the threshold of spike generation in ORCs.
Collapse
Affiliation(s)
- F Kawai
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Aichi, 470-1192, Japan.
| | | |
Collapse
|
36
|
Abstract
Mammalian photoreceptors are hyperpolarized by a light stimulus and are commonly thought to be nonspiking neurons. We used the whole-cell patch-clamp technique on surgically excised human retina to examine whether human photoreceptors can elicit action potentials. We discovered that human rod photoreceptors express voltage-gated Na(+) channels, and generate Na(+) action potentials, in response to membrane depolarization from membrane potentials of -60 or -70 mV. Na(+) spikes in human rods were elicited at the termination of a light response that hyperpolarized the potential well below -50 mV. This served to amplify the release of a neurotransmitter when a bright light is turned off, and thus selectively amplify the off response to the light signal.
Collapse
Affiliation(s)
- F Kawai
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
| | | | | | | |
Collapse
|
37
|
Abstract
Effects of cGMP on voltage-gated currents in the somatic membrane of isolated newt olfactory receptor cells were investigated using the whole-cell mode of the patch-clamp technique. Under voltage clamp, membrane depolarization generated time- and voltage-dependent current responses, a transient inward current and a sustained outward current. When cGMP or a membrane permeant analog of cGMP, 8-p-chlorophenylthio-cGMP (CPT-cGMP), was applied to the recorded cell, the amplitude of the transient inward current increased markedly, but that of the sustained outward current did not change significantly. When each current was isolated by pharmacological agents, 0.1 mM CPT-cGMP increased the peak amplitude of a Na(+) current (I(Na)) by approximately 40%, a T-type Ca(2+) current (I(Ca,T)) by approximately 40%, and an L-type Ca(2+)current (I(Ca,L)) by approximately 10%; however it did not change significantly the amplitude of a delayed rectifier K(+) current (I(K)). A selective cGMP-dependent protein kinase inhibitor, KT5823, blocked the enhancement by cGMP of I(Na) and I(Ca,T), suggesting that cGMP increases these currents via cGMP-dependent phosphorylation. Under current-clamp conditions, application of CPT-cGMP lowered the current threshold of action potentials induced by current injection, and increased the maximum spike frequency in response to strong stimuli. We suggest that cGMP may lower the threshold in olfactory perception by decreasing the current threshold to generate spikes, and also prevent the saturation of odor signals by increasing the maximum spike frequency.
Collapse
Affiliation(s)
- F Kawai
- Department of Physiology, School of Medicine, Fujita Health University, 1-98 Dengakugakubo, Kutsukakechou, Toyoake, Aichi, 470-1192, Japan.
| | | |
Collapse
|
38
|
Abstract
Various soil samples were collected to screen the presence of microorganisms which have ability to degrade TOE. One strain (AKU-883) with good TOE degrading activity was isolated and identified as Burkholderia cepacia and the extracellular enzyme was purified to homogeneity. The purification was achieved by ultrafiltration, Super Q anion-exchange chromatography and Superdex 200HR gel-filtration in the presence of Triton X. The enzyme was purified to 85-fold, and specific activity of 4.910 kU mg protein(-1). The peak preparation on gel filtration showed a single band of 34 kDa on SDS-PAGE and native PAGE which indicate the monomeric nature of the enzyme. The pI of the enzyme was 6.3. The enzyme showed the maximum activity at pH 9 and 65 degrees C, and was stable in the range of pH 5--10 and up to 60 degrees C. Almost all the activity (92%) was kept after incubation for more than 1 week at 50 degrees C (pH 7.3). High activities remained even in water-miscible solvents such as ethanol, dimethyl formamide, diisopropyl ether, and dioxane. The N-terminal 16 amino acid residues were determined as A-N-G-Y-A-A-T-R-Y-P-I-I-L-V-G-G, which showed a consensus sequence for lipases from Burkholderia species. Thus the enzyme was concluded to be a kind of lipase.
Collapse
Affiliation(s)
- R Ishimoto
- Research Institute for Bioresources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan.
| | | | | |
Collapse
|
39
|
Abstract
Odorants are known to suppress the cyclic nucleotide-gated (CNG) current in olfactory receptor cells. It is unclear, however, whether odorants suppress the olfactory CNG current directly or whether they suppress the current by decreasing the second messenger (cAMP) through the activation of phosphodiesterase. We found that odorants also suppress CNG currents in photoreceptor cells. Under voltage clamp, an odorant puff immediately suppressed the currents induced by the intracellular cGMP in isolated newt rods and cones. Odorants also suppressed the currents induced by another cGMP analog (8-p-chlorophenylthio-cGMP, which strongly resists hydrolysis by phosphodiesterase), suggesting that the second messenger metabolism via phosphodiesterase is not involved in the suppression by odorants. This suggests that odorants suppress the CNG currents directly rather than via the second messenger system in photoreceptors, and also likely in olfactory receptor cells.
Collapse
Affiliation(s)
- F Kawai
- Department of Physiology, School of Medicine, Fujita Health University, 1-98 Dengakugakubo, Kutsukakechou, Toyoake, 470-1192, Aichi, Japan.
| | | |
Collapse
|
40
|
Abstract
Acid- and aluminum (Al)-tolerant microorganisms were isolated from tea fields, from which six strains were selected and identified as Cryptococcus humicola, Rhodotorula glutinis, Aspergillus flavus Link, Penicillium sp., Penicillium janthinellum Biourge and Trichoderma asperellum. They were tolerant to Al up to 100-200 mM and could grow at low pH, 2.5-2.2. In a glucose medium (pH 3.5) the pH of the spent medium decreased to below 3.0. The toxic inorganic monomeric Al in the spent medium decreased with three strains (A. flavus F-6b, Penicillium sp. F-8b and P. janthinellum F-13), but the total Al remained constant for all strains. In a soil extract medium (pH 3.5), the pH of the spent medium of all strains increased to around 6.0-7. 2 and total Al in the spent medium was removed by precipitation due to pH increase. Thus, different tolerance mechanisms were suggested in glucose and soil extract media.
Collapse
Affiliation(s)
- F Kawai
- Research Institute for Bioresources, Okayama University, 710-0046, Kurashiki, Japan.
| | | | | |
Collapse
|
41
|
Abstract
Odorants are known to suppress non-selectively voltage-gated currents in olfactory receptor cells. We found that odorants also suppress voltage-gated currents in neurons of outside of the olfactory system. Under voltage clamp, odorants such as amyl acetate, limonene, and acetophenone suppressed non-selectively voltage-gated currents (a Ca(2+) current, a delayed rectifier K(+) current, a fast transient K(+) current, and an anomalous rectifier K(+) current) in horizontal cells from the goldfish retina. An amyl acetate puff completely and immediately suppressed the Ca(2+) current (I(Ca)) and the delayed rectifier K(+) current induced by repetitive depolarizations, suggesting that amyl acetate is a closed-channel blocker. Odorants did not change significantly the activation curve of I(Ca), but made the slope of inactivation curve of I(Ca) gentler and shifted its half-inactivation voltage toward a negative voltage. These results are similar to the effects of odorants on voltage-gated currents in olfactory receptor cells. This suggests that odorants may suppress the voltage-gated currents in retinal horizontal cells by the same mechanism described in olfactory receptor cells.
Collapse
Affiliation(s)
- F Kawai
- Department of Physiology, School of Medicine, Fujita Health University, 1-98 Dengakugakubo, Kutsukakechou, Toyoake, Aichi, Japan.
| | | |
Collapse
|
42
|
Utsunomiya Y, Nakayama T, Oohira H, Hirota R, Mori T, Kawai F, Ueda T. Purification and inactivation by substrate of an allene oxide synthase (CYP74) from corn (Zea mays L.) seeds. Phytochemistry 2000; 53:319-323. [PMID: 10703051 DOI: 10.1016/s0031-9422(99)00534-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The allene oxide synthase (AOS) was purified from corn (Zea mays) seeds to homogeneity and characterized partially. The corn AOS was a hemoprotein cytochrome P450 with a molecular weight and pI of 53,000 and 6.0, respectively. The corn AOS was found to be irreversibly inactivated by a substrate, 13-hydroperoxyoctadienoic acid. The rate of the enzyme inactivation was higher at low pHs.
Collapse
Affiliation(s)
- Y Utsunomiya
- Faculty of Nutrition, Kobe Gakuin University, Hyogo, Japan
| | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
Mechanisms underlying suppression of T- and L-type Ca2+ currents (I(Ca,T) and I(Ca,L)) by odorants were investigated in newt olfactory receptor cells (ORCs) using the whole-cell version of the patch-clamp technique. Under voltage clamp, odorants (amyl acetate, limonene and acetophenone) reversibly suppressed I(Ca,T) and I(Ca, L). These currents disappeared completely within 150 ms following amyl acetate puffs, and recovered in approximately 1 s after the washout. Hyperpolarization of the membrane greatly relieved the odorant block of I(Ca,T) and I(Ca,L). The activation curves of both currents were not changed significantly by odorants, while their inactivation curves were shifted to negative voltages. Half-inactivation voltages of I(Ca,T) were - 66 mV (control), - 102 mV (amyl acetate), - 101 mV (limonene) and - 105 mV (acetophenone) (all 0.3 mM); those of I(Ca,L) were -33 mV (control), - 61 mV (amyl acetate), - 59 mV (limonene), and - 63 mV (acetophenone) (all 0.3 mM). These phenomena are similar to the effects of local anesthetics on I(Ca) in various preparations and also similar to the effects of odorants on I(Na) in ORCs, suggesting that these types of suppression are caused by the same mechanism.
Collapse
Affiliation(s)
- F Kawai
- Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
| |
Collapse
|
44
|
Abstract
Adrenaline is known to affect action potentials induced by the step current injection in an olfactory receptor cell (ORC). It is unclear, however, whether it also modulates action potentials induced by odor stimuli. In the present study, the effects of adrenaline on action potentials in ORCs were investigated quantitatively using a computer simulation. Adrenaline suppressed simulated action potentials induced by step current injection near threshold, and increased spike frequency to strong stimuli by 8-25%. Similar effects were obtained by applying a pseudo-transduction current to a model cell. Surprisingly, adrenaline markedly increased spike frequency to strong stimuli by 30-140%, and increased the slope of the stimulus-response relation compared with that of the step current injection. This suggests that adrenaline enhances odorant contrast in olfactory perception by modulating signal encoding of ORCs.
Collapse
Affiliation(s)
- F Kawai
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
| |
Collapse
|
45
|
Ono T, Kawai F, Nakamura M, Taniguchi N, Itoh K. [Ultrasound-guided fine-needle aspiration cytology for neck lesions]. Rinsho Byori 1999; 47:1173-6. [PMID: 10639829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
In 1997, 240 cases of ultrasound-guided fine-needle aspiration cytology (FNAC) were performed for neck lesion at Jichi Medical School Hospital. We compared the preoperative cytology findings with postoperative pathologic results for 63 cases (56 lesions) from patients who underwent surgery or open biopsy. The sensitivity, specificity and accuracy of cytological diagnosis were 93.5%, 100% and 96.2%, respectively. There were 2 false negative cases in thyroid gland, which were follicular and medullary carcinomas. Insufficient material for cytological analysis was obtained in 62 of 240 cases (25.8%). Since FNAC can provide high accuracy, we need to reduce insufficient material cases.
Collapse
Affiliation(s)
- T Ono
- Department of Clinical Pathology, Jichi Medical School, Tochigi-pref
| | | | | | | | | |
Collapse
|
46
|
Kawai F. Sphingomonads involved in the biodegradation of xenobiotic polymers. J Ind Microbiol Biotechnol 1999; 23:400-407. [PMID: 11423961 DOI: 10.1038/sj.jim.2900730] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/1999] [Accepted: 07/17/1999] [Indexed: 11/08/2022]
Abstract
Sphingomonads involved in the microbial degradation of xenobiotic polymers are introduced. The metabolism of polyethylene glycol was the primary focus of the study. Several others, including polyvinyl alcohol, polyethylene and polyaspartate were also studied. It is suggested that these xenobiotic polymers are metabolized by intracellular enzymes located in the periplasmic space or bound to membranes, indicating that transport of these polymers through outer membranes is requisite for their metabolism. Involvement of specific membrane structures of sphingomonads such as unusual sphingolipids is suggested for membrane transport of xenobiotic compounds, especially hydrophobic materials.
Collapse
Affiliation(s)
- F Kawai
- Research Institute for Bioresources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan
| |
Collapse
|
47
|
Abstract
The kinetics of glutamate concentration in the synaptic cleft is an important determinant of synaptic function. To elucidate peak concentration of glutamate released from a single vesicle in the cleft, spontaneous excitatory postsynaptic currents (sEPSCs) in Off-bipolar cells from the sliced newt retina were analyzed using whole-cell patch clamp recording and the computer simulation. The sEPSCs were blocked by an AMPA/kainate (KA) antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and prolonged by cyclothiazide. However, an N-methyl-D-aspartate (NMDA) antagonist, D-2-amino-5-phosphonopentanoic acid (D-AP5), was ineffective. These suggest that sEPSCs in Off-bipolar cells are mediated exclusively by AMPA/KA receptors. sEPSCs simulated by a detailed kinetic model of AMPA receptor best approximated the data, when peak glutamate concentration was 10 microM. Therefore, it was concluded that peak concentration of glutamate released from a single vesicle would be elevated to approximately 10 microM at the newt Off-bipolar dendrite.
Collapse
Affiliation(s)
- F Kawai
- Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
| |
Collapse
|
48
|
Abstract
Effects of odorants on a delayed rectifier potassium current (IK) in newt olfactory receptor cells (ORCs) were investigated using the whole-cell version of the patch-clamp technique. Under voltage clamp, odorants (amyl acetate, limonene and acetophenone) reversibly suppressed I(K) without shifting its I-V curve. An amyl acetate puff completely suppressed I(K) induced by the first step pulse of repetitive depolarizations, suggesting that binding of an odorant molecule to the open channel is not required to block the channel. Although it is known that odorants suppress Na+ and Ca2+ currents (I(Na), I(Ca)) by shifting their inactivation curves to a negative voltage, odorants did not shift the inactivation curve of I(K) significantly. This suggests that odorants suppress I(K) without changing its voltage dependence. Therefore, the blocking mechanisms by odorants of I(K) in ORCs are different from those of I(Na) and I(Ca).
Collapse
Affiliation(s)
- F Kawai
- Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
| |
Collapse
|
49
|
Kawai F, Sterling P. AMPA receptor activates a G-protein that suppresses a cGMP-gated current. J Neurosci 1999; 19:2954-9. [PMID: 10191313 PMCID: PMC6782299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
The AMPA receptor, ubiquitous in brain, is termed "ionotropic" because it gates an ion channel directly. We found that an AMPA receptor can also modulate a G-protein to gate an ion channel indirectly. Glutamate applied to a retinal ganglion cell briefly suppresses the inward current through a cGMP-gated channel. AMPA and kainate also suppress the current, an effect that is blocked both by their general antagonist CNQX and also by the relatively specific AMPA receptor antagonist GYKI-52466. Neither NMDA nor agonists of metabotropic glutamate receptors are effective. The AMPA-induced suppression of the cGMP-gated current is blocked when the patch pipette includes GDP-beta-S, whereas the suppression is irreversible when the pipette contains GTP-gamma-S. This suggests a G-protein mediator, and, consistent with this, pertussis toxin blocks the current suppression. Nitric oxide (NO) donors induce the current suppressed by AMPA, and phosphodiesterase inhibitors prevent the suppression. Apparently, the AMPA receptor can exhibit a "metabotropic" activity that allows it to antagonize excitation evoked by NO.
Collapse
Affiliation(s)
- F Kawai
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6058, USA
| | | |
Collapse
|
50
|
Abstract
AIM The increased echogenicity of medullary pyramids in neonates and children is poorly understood. Hence we conducted a prospective ultrasound study of the kidneys of neonates and fetuses. Hence we conducted a prospective ultrasound study of the kidneys of neonates and fetuses. PATIENTS AND METHODS Ultrasound images of kidneys in neonates and fetuses in late pregnancy were analysed. RESULTS Thirteen percent of the studied neonates showed hyperechogenicity in the renal papillae that disappeared spontaneously within 1 week, although no hyperechoic papillae were seen in any of the fetuses. Urine volume of the neonates with hyperechogenicity was significantly less than that of those without it. CONCLUSION The fact that no hyperechoic findings appeared before the 34th week of gestation suggests that maturation of renal tubules and ability to concentrate urinary substances were contributing factors. Because only the tips of the pyramids were hyperechogenic, however, the term hyperechoic papillae would seem more appropriate than hyperechoic pyramids, the term generally used today.
Collapse
Affiliation(s)
- M Nakamura
- Department of Clinical Pathology, Jichi Medical School, Tochigi, Japan
| | | | | | | | | | | | | |
Collapse
|