1
|
Ando R, Shiraki Y, Miyai Y, Shimizu H, Furuhashi K, Minatoguchi S, Kato K, Kato A, Iida T, Mizutani Y, Ito K, Asai N, Mii S, Esaki N, Takahashi M, Enomoto A. Meflin is a marker of pancreatic stellate cells involved in fibrosis and epithelial regeneration in the pancreas. J Pathol 2024; 262:61-75. [PMID: 37796386 DOI: 10.1002/path.6211] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 07/18/2023] [Accepted: 08/25/2023] [Indexed: 10/06/2023]
Abstract
Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin+ ) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.
Collapse
Affiliation(s)
- Ryota Ando
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuki Miyai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroki Shimizu
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kazuhiro Furuhashi
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shun Minatoguchi
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Katsuhiro Kato
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akira Kato
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tadashi Iida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuyuki Mizutani
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kisuke Ito
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Naoya Asai
- Department of Molecular Pathology, Fujita Health University, Toyoake, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahide Takahashi
- Division of International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Gifu, Japan
| |
Collapse
|
2
|
Mori N, Esaki N, Shimoyama Y, Shiraki Y, Asai N, Sakai T, Nishida Y, Takahashi M, Enomoto A, Mii S. Significance of expression of CD109 in osteosarcoma and its involvement in tumor progression via BMP signaling. Pathol Res Pract 2023; 245:154443. [PMID: 37030166 DOI: 10.1016/j.prp.2023.154443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/09/2023]
Abstract
Osteosarcoma, the most common primary malignant bone tumor, is defined by the formation of neoplastic osteoid and/or bone. This sarcoma is a highly heterogeneous disease with a wide range of patient outcomes. CD109 is a glycosylphosphatidylinositol-anchored glycoprotein that is highly expressed in various types of malignant tumors. We previously reported that CD109 is expressed in osteoblasts and osteoclasts in normal human tissues and plays a role in bone metabolism in vivo. While CD109 has been shown to promote various carcinomas through the downregulation of TGF-β signaling, the role and mechanism of CD109 in sarcomas remain largely unknown. In this study, we investigated the molecular function of CD109 in sarcomas using osteosarcoma cell lines and tissue. Semi-quantitative immunohistochemical analysis using human osteosarcoma tissue revealed a significantly worse prognosis in the CD109-high group compared with the CD109-low group. We found no association between CD109 expression and TGF-β signaling in osteosarcoma cells. However, enhancement of SMAD1/5/9 phosphorylation was observed in CD109 knockdown cells under bone morphogenetic protein-2 (BMP-2) stimulation. We also performed immunohistochemical analysis for phospho-SMAD1/5/9 using human osteosarcoma tissue and found a negative correlation between CD109 expression and SMAD1/5/9 phosphorylation. In vitro wound healing assay showed that osteosarcoma cell migration was significantly attenuated in CD109-knockdown cells compared with control cells in the presence of BMP. These results suggest that CD109 is a poor prognostic factor in osteosarcoma and affects tumor cell migration via BMP signaling.
Collapse
|
3
|
Shiraki Y, Mii S, Esaki N, Enomoto A. Possible disease-protective roles of fibroblasts in cancer and fibrosis and their therapeutic application. Nagoya J Med Sci 2022; 84:484-496. [PMID: 36237894 PMCID: PMC9529631 DOI: 10.18999/nagjms.84.3.484] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/06/2022] [Indexed: 11/28/2022]
Abstract
Cancer and fibrotic diseases are characterized by continuous inflammation, tissue wounds, and injuries. Cancer is a "wound that does not heal," and the uncontrolled proliferation of cancer cells disrupts normal tissue integrity and induces stromal fibroinflammatory reactions. Fibroblasts proliferate extensively in the stroma, playing a major role in the development of these diseases. There has been considerable evidence that fibroblasts contribute to fibrosis and tissue stiffening and promote disease progression via multiple mechanisms. However, recent emerging findings, mainly derived from single-cell transcriptomic analysis, indicated that fibroblasts are functionally heterogeneous, leading to the hypothesis that both disease-promoting and -restraining fibroblasts exist. We recently showed that a fibroblast population, defined by the expression of the glycosylphosphatidylinositol-anchored membrane protein Meflin may suppress but not promote fibrotic response and disease progression in cancer and fibrotic diseases. Although currently hypothetical, the primary function of Meflin-positive fibroblasts may be tissue repair after injury and cancer initiation occurred. This observation has led to the proposal of a potential therapy that converts the phenotype of fibroblasts from pro-tumor to anti-tumor. In this short review, we summarize our recent findings on the function of Meflin in the context of cancer and fibrotic diseases and discuss how we can utilize this knowledge on fibroblasts in translational medicine. We also discuss several aspects of the interpretation of survival analysis data, such as Kaplan-Meier analysis, to address the function of specific genes expressed in fibroblasts.
Collapse
Affiliation(s)
- Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
4
|
Iida T, Mizutani Y, Esaki N, Ponik SM, Burkel BM, Weng L, Kuwata K, Masamune A, Ishihara S, Haga H, Kataoka K, Mii S, Shiraki Y, Ishikawa T, Ohno E, Kawashima H, Hirooka Y, Fujishiro M, Takahashi M, Enomoto A. Pharmacologic conversion of cancer-associated fibroblasts from a protumor phenotype to an antitumor phenotype improves the sensitivity of pancreatic cancer to chemotherapeutics. Oncogene 2022; 41:2764-2777. [PMID: 35414659 DOI: 10.1038/s41388-022-02288-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [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: 07/27/2021] [Revised: 03/05/2022] [Accepted: 03/18/2022] [Indexed: 12/17/2022]
Abstract
Previous therapeutic attempts to deplete cancer-associated fibroblasts (CAFs) or inhibit their proliferation in pancreatic ductal adenocarcinoma (PDAC) were not successful in mice or patients. Thus, CAFs may be tumor suppressive or heterogeneous, with distinct cancer-restraining and -promoting CAFs (rCAFs and pCAFs, respectively). Here, we showed that induced expression of the glycosylphosphatidylinositol-anchored protein Meflin, a rCAF-specific marker, in CAFs by genetic and pharmacological approaches improved the chemosensitivity of mouse PDAC. A chemical library screen identified Am80, a synthetic, nonnatural retinoid, as a reagent that effectively induced Meflin expression in CAFs. Am80 administration improved the sensitivity of PDAC to chemotherapeutics, accompanied by increases in tumor vessel area and intratumoral drug delivery. Mechanistically, Meflin was involved in the suppression of tissue stiffening by interacting with lysyl oxidase to inhibit its collagen crosslinking activity. These data suggested that modulation of CAF heterogeneity may represent a strategy for PDAC treatment.
Collapse
Affiliation(s)
- Tadashi Iida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuyuki Mizutani
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Suzanne M Ponik
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian M Burkel
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Liang Weng
- Department of Oncology, Xiangya Cancer Center, Xiangya Hospital, Central South University, Changsha, China
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan
| | - Atsushi Masamune
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | - Hisashi Haga
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Kunio Kataoka
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takuya Ishikawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Eizaburo Ohno
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroki Kawashima
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
| | - Yoshiki Hirooka
- Department of Gastroenterology and Hepatology, Fujita Health University, Toyoake, Aichi, Japan
| | - Mitsuhiro Fujishiro
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masahide Takahashi
- International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| |
Collapse
|
5
|
Ichihara R, Shiraki Y, Mizutani Y, Iida T, Miyai Y, Esaki N, Kato A, Mii S, Ando R, Hayashi M, Takami H, Fujii T, Takahashi M, Enomoto A. Matrix remodeling-associated protein 8 is a marker of a subset of cancer-associated fibroblasts in pancreatic cancer. Pathol Int 2022; 72:161-175. [PMID: 35020975 PMCID: PMC9305816 DOI: 10.1111/pin.13198] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/11/2021] [Indexed: 02/06/2023]
Abstract
Cancer‐associated fibroblasts (CAFs), a compartment of the tumor microenvironment, were previously thought to be a uniform cell population that promotes cancer progression. However, recent studies have shown that CAFs are heterogeneous and that there are at least two types of CAFs, that is, cancer‐promoting and ‐restraining CAFs. We previously identified Meflin as a candidate marker of cancer‐restraining CAFs (rCAFs) in pancreatic ductal adenocarcinoma (PDAC). The precise nature of rCAFs, however, has remained elusive owing to a lack of understanding of their comprehensive gene signatures. Here, we screened genes whose expression correlated with Meflin in single‐cell transcriptomic analyses of human cancers. Among the identified genes, we identified matrix remodeling‐associated protein 8 (MXRA8), which encodes a type I transmembrane protein with unknown molecular function. Analysis of MXRA8 expression in human PDAC samples showed that MXRA8 was differentially co‐expressed with other CAF markers. Moreover, in patients with PDAC or syngeneic tumors developed in MXRA8‐knockout mice, MXRA8 expression did not affect the roles of CAFs in cancer progression, and the biological importance of MXRA8+ CAFs is still unclear. Overall, we identified MXRA8 as a new CAF marker; further studies are needed to determine the relevance of this marker.
Collapse
Affiliation(s)
- Ryosuke Ichihara
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuyuki Mizutani
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tadashi Iida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuki Miyai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akira Kato
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ryota Ando
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masamichi Hayashi
- Department of Gastroenterological Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hideki Takami
- Department of Gastroenterological Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tsutomu Fujii
- Department of Surgery and Science, Faculty of Medicine, Academic Assembly, University of Toyama, Toyama, Japan
| | - Masahide Takahashi
- International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
6
|
Esaki N, Enomoto A, Takagishi M, Mizutani Y, Iida T, Ushida K, Shiraki Y, Mii S, Takahashi M. The Daple-CK1ε complex regulates Dvl2 phosphorylation and canonical Wnt signaling. Biochem Biophys Res Commun 2020; 532:406-413. [PMID: 32888647 DOI: 10.1016/j.bbrc.2020.08.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 01/22/2023]
Abstract
The canonical Wnt signaling pathway plays a crucial role in embryonic development, tissue homeostasis and cancer progression. The binding of Wnt ligands to their cognate receptors, the Frizzled (Fzd) family of proteins, recruits Dishevelled segment polarity protein (Dvl) to the plasma membrane and induces its phosphorylation via casein kinase 1 (CK1), which leads to the activation of β-catenin. Previous studies showed that Dishevelled-associating protein with a high frequency of leucine residues (Daple) is an important component of the Wnt signaling pathway and essential for Dvl phosphorylation. However, the mechanism by which Daple promotes CK1-mediated phosphorylation of Dvl is not fully understood. In this study, we found that Daple overexpression induced CK1ε-mediated Dvl2 phosphorylation at threonine 224 (Thr224). A Daple mutant (Daple ΔGCV) that lacks a carboxyl-terminal motif to associate with Dvl, retained the ability to interact with CK1ε, but did not induce Dvl phosphorylation, suggesting the importance of the Daple/Dvl/CK1ε trimeric protein complex. We further found that Thr224 phosphorylation of Dvl was required for full activation of β-catenin transcriptional activity. Consistent with this, wild-type Daple promoted β-catenin transcriptional activity, following dissociation of β-catenin and axin. Finally, Wnt3a stimulation increased the membrane localization of Daple and its association with Dvl, and Daple knockdown attenuated Wnt3a-mediated β-catenin transcriptional activity. Collectively, these data suggested a essential role of spatial Daple localization in CK1ε-mediated activation of Dvl in the canonical Wnt signaling pathway.
Collapse
Affiliation(s)
- Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Maki Takagishi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yasuyuki Mizutani
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan; Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Tadashi Iida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan; Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Kaori Ushida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan; International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, 470-1192, Japan.
| |
Collapse
|
7
|
Miyai Y, Esaki N, Takahashi M, Enomoto A. Cancer-associated fibroblasts that restrain cancer progression: Hypotheses and perspectives. Cancer Sci 2020; 111:1047-1057. [PMID: 32060987 PMCID: PMC7156845 DOI: 10.1111/cas.14346] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 01/26/2020] [Accepted: 02/02/2020] [Indexed: 12/11/2022] Open
Abstract
The roles of cancer‐associated fibroblasts (CAF) in the progression of various types of cancers are well established. CAF promote cancer progression through pleiotropic mechanisms, including the secretion of soluble factors and extracellular matrix, physical interactions with cancer cells, and the regulation of angiogenesis, immunity and metabolism. Their contribution to therapeutic resistance is also well appreciated. Therefore, CAF have been considered as a therapeutic target in cancer. However, recent studies in autochthonous pancreatic cancer models suggest that specific subset(s) of CAF exhibit cancer‐restraining roles, indicating that CAF are functionally and molecularly heterogeneous, which is supported by recent single‐cell transcriptome analyses. While cancer‐promoting CAF (pCAF) have been extensively studied, the nature and specific marker(s) of cancer‐restraining CAF (rCAF) have remained uncharacterized. Interestingly, a recent study provided insight into the nature of rCAF and suggested that they may share molecular properties with pancreatic stellate cells (PSC) and mesenchymal stem/stromal cells (MSC). Complicating this finding is that PSC and MSC have been shown to promote the formation of a tumor‐permissive and tumor‐promoting environment in xenograft tumor models. However, these cells undergo significant transcriptional and epigenetic changes during ex vivo culture, which confounds the interpretation of experimental results based on the use of cultured cells. In this short review, we describe recent studies and hypotheses on the identity of rCAF and discuss their analogy to fibroblasts that suppress fibrosis in fibrotic diseases. Finally, we discuss how these findings can be exploited to develop novel anticancer therapies in the future.
Collapse
Affiliation(s)
- Yuki Miyai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
8
|
Miyai Y, Esaki N, Takahashi M, Enomoto A. Cancer-associated fibroblasts that restrain cancer progression: Hypotheses and perspectives. Cancer Sci 2020. [PMID: 32060987 DOI: 10.1111/cas.14346.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The roles of cancer-associated fibroblasts (CAF) in the progression of various types of cancers are well established. CAF promote cancer progression through pleiotropic mechanisms, including the secretion of soluble factors and extracellular matrix, physical interactions with cancer cells, and the regulation of angiogenesis, immunity and metabolism. Their contribution to therapeutic resistance is also well appreciated. Therefore, CAF have been considered as a therapeutic target in cancer. However, recent studies in autochthonous pancreatic cancer models suggest that specific subset(s) of CAF exhibit cancer-restraining roles, indicating that CAF are functionally and molecularly heterogeneous, which is supported by recent single-cell transcriptome analyses. While cancer-promoting CAF (pCAF) have been extensively studied, the nature and specific marker(s) of cancer-restraining CAF (rCAF) have remained uncharacterized. Interestingly, a recent study provided insight into the nature of rCAF and suggested that they may share molecular properties with pancreatic stellate cells (PSC) and mesenchymal stem/stromal cells (MSC). Complicating this finding is that PSC and MSC have been shown to promote the formation of a tumor-permissive and tumor-promoting environment in xenograft tumor models. However, these cells undergo significant transcriptional and epigenetic changes during ex vivo culture, which confounds the interpretation of experimental results based on the use of cultured cells. In this short review, we describe recent studies and hypotheses on the identity of rCAF and discuss their analogy to fibroblasts that suppress fibrosis in fibrotic diseases. Finally, we discuss how these findings can be exploited to develop novel anticancer therapies in the future.
Collapse
Affiliation(s)
- Yuki Miyai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
9
|
Mizutani Y, Kobayashi H, Iida T, Asai N, Masamune A, Hara A, Esaki N, Ushida K, Mii S, Shiraki Y, Ando K, Weng L, Ishihara S, Ponik SM, Conklin MW, Haga H, Nagasaka A, Miyata T, Matsuyama M, Kobayashi T, Fujii T, Yamada S, Yamaguchi J, Wang T, Woods SL, Worthley D, Shimamura T, Fujishiro M, Hirooka Y, Enomoto A, Takahashi M. Meflin-Positive Cancer-Associated Fibroblasts Inhibit Pancreatic Carcinogenesis. Cancer Res 2019; 79:5367-5381. [PMID: 31439548 DOI: 10.1158/0008-5472.can-19-0454] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [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: 02/05/2019] [Revised: 06/17/2019] [Accepted: 08/01/2019] [Indexed: 11/16/2022]
Abstract
Cancer-associated fibroblasts (CAF) constitute a major component of the tumor microenvironment. Recent observations in genetically engineered mouse models and clinical studies have suggested that there may exist at least two functionally different populations of CAFs, that is, cancer-promoting CAFs (pCAF) and cancer-restraining CAFs (rCAF). Although various pCAF markers have been identified, the identity of rCAFs remains unknown because of the lack of rCAF-specific marker(s). In this study, we found that Meflin, a glycosylphosphatidylinositol-anchored protein that is a marker of mesenchymal stromal/stem cells and maintains their undifferentiated state, is expressed by pancreatic stellate cells that are a source of CAFs in pancreatic ductal adenocarcinoma (PDAC). In situ hybridization analysis of 71 human PDAC tissues revealed that the infiltration of Meflin-positive CAFs correlated with favorable patient outcome. Consistent herewith, Meflin deficiency led to significant tumor progression with poorly differentiated histology in a PDAC mouse model. Similarly, genetic ablation of Meflin-positive CAFs resulted in poor differentiation of tumors in a syngeneic transplantation model. Conversely, delivery of a Meflin-expressing lentivirus into the tumor stroma or overexpression of Meflin in CAFs suppressed the growth of xenograft tumors. Lineage tracing revealed that Meflin-positive cells gave rise to α-smooth muscle actin-positive CAFs that are positive or negative for Meflin, suggesting a mechanism for generating CAF heterogeneity. Meflin deficiency or low expression resulted in straightened stromal collagen fibers, which represent a signature for aggressive tumors, in mouse or human PDAC tissues, respectively. Together, the data suggest that Meflin is a marker of rCAFs that suppress PDAC progression. SIGNIFICANCE: Meflin marks and functionally contributes to a subset of cancer-associated fibroblasts that exert antitumoral effects.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/20/5367/F1.large.jpg.
Collapse
Affiliation(s)
- Yasuyuki Mizutani
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroki Kobayashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- School of Medicine, University of Adelaide and South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Tadashi Iida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Naoya Asai
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Molecular Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Masamune
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Akitoshi Hara
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobutoshi Esaki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kaori Ushida
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Mii
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yukihiro Shiraki
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kenju Ando
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Liang Weng
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | - Suzanne M Ponik
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Matthew W Conklin
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Hisashi Haga
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Arata Nagasaka
- Division of Anatomy, Department of Human Development and Fostering, Meikai University School of Dentistry, Sakado, Japan
| | - Takaki Miyata
- Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Makoto Matsuyama
- Division of Molecular Genetics, Shigei Medical Research Institute, Okayama, Japan
| | - Tomoe Kobayashi
- Division of Molecular Genetics, Shigei Medical Research Institute, Okayama, Japan
| | - Tsutomu Fujii
- Department of Surgery and Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Suguru Yamada
- Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Junpei Yamaguchi
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tongtong Wang
- School of Medicine, University of Adelaide and South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Susan L Woods
- School of Medicine, University of Adelaide and South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Daniel Worthley
- School of Medicine, University of Adelaide and South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Teppei Shimamura
- Division of Systems Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mitsuhiro Fujishiro
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshiki Hirooka
- Department of Liver, Biliary Tract and Pancreas Diseases, Fujita Health University, Toyoake, Japan
| | - Atsushi Enomoto
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Masahide Takahashi
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
- Division of Molecular Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
10
|
Wang X, Enomoto A, Weng L, Mizutani Y, Abudureyimu S, Esaki N, Tsuyuki Y, Chen C, Mii S, Asai N, Haga H, Ishida S, Yokota K, Akiyama M, Takahashi M. Girdin/GIV regulates collective cancer cell migration by controlling cell adhesion and cytoskeletal organization. Cancer Sci 2018; 109:3643-3656. [PMID: 30194792 PMCID: PMC6215880 DOI: 10.1111/cas.13795] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 12/28/2022] Open
Abstract
Pathological observations show that cancer cells frequently invade the surrounding stroma in collective groups rather than through single cell migration. Here, we studied the role of the actin-binding protein Girdin, a specific regulator of collective migration of neuroblasts in the brain, in collective cancer cell migration. We found that Girdin was essential for the collective migration of the skin cancer cell line A431 on collagen gels as well as their fibroblast-led collective invasion in an organotypic culture model. We provide evidence that Girdin binds to β-catenin that plays important roles in the Wnt signaling pathway and in E-cadherin-mediated cell-cell adhesion. Girdin-depleted cells displayed scattering and impaired E-cadherin-specific cell-cell adhesion. Importantly, Girdin depletion led to impaired cytoskeletal association of the β-catenin complex, which was accompanied by changes in the supracellular actin cytoskeletal organization of cancer cell cohorts on collagen gels. Although the underlying mechanism is unclear, this observation is consistent with the established role of the actin cytoskeletal system and cell-cell adhesion in the collective behavior of cells. Finally, we showed the correlation of the expression of Girdin with that of the components of the E-cadherin complex and the differentiation of human skin cancer. Collectively, our results suggest that Girdin is an important modulator of the collective behavior of cancer cells.
Collapse
Affiliation(s)
- Xiaoze Wang
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Atsushi Enomoto
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Liang Weng
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Yasuyuki Mizutani
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Shaniya Abudureyimu
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Nobutoshi Esaki
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Yuta Tsuyuki
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Chen Chen
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Shinji Mii
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Naoya Asai
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Hisashi Haga
- Transdisciplinary Life Science CourseFaculty of Advanced Life ScienceHokkaido UniversitySapporoJapan
| | - Sumire Ishida
- Transdisciplinary Life Science CourseFaculty of Advanced Life ScienceHokkaido UniversitySapporoJapan
| | - Kenji Yokota
- Department of DermatologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Masashi Akiyama
- Department of DermatologyNagoya University Graduate School of MedicineNagoyaJapan
| | - Masahide Takahashi
- Department of PathologyNagoya University Graduate School of MedicineNagoyaJapan
| |
Collapse
|
11
|
Esaki N, Ohkawa Y, Hashimoto N, Tsuda Y, Ohmi Y, Bhuiyan RH, Kotani N, Honke K, Enomoto A, Takahashi M, Furukawa K, Furukawa K. ASC amino acid transporter 2, defined by enzyme-mediated activation of radical sources, enhances malignancy of GD2-positive small-cell lung cancer. Cancer Sci 2018; 109:141-153. [PMID: 29151270 PMCID: PMC5765286 DOI: 10.1111/cas.13448] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/31/2017] [Accepted: 11/12/2017] [Indexed: 12/20/2022] Open
Abstract
Ganglioside GD2 is specifically expressed in small‐cell lung cancer (SCLC) cells, leading to enhancement of malignant phenotypes, such as cell proliferation and migration. However, how GD2 promotes malignant phenotypes in SCLC cells is not well known. In this study, to reveal the mechanisms by which GD2 increases malignant phenotypes in SCLC cells, we used enzyme‐mediated activation of radical sources combined with mass spectrometry in GD2+SCLC cells. Consequently, we identified ASC amino acid transporter 2 (ASCT2), a major glutamine transporter, which coordinately works with GD2. We showed that ASCT2 was highly expressed in glycolipid‐enriched microdomain/rafts in GD2+SCLC cells, and colocalized with GD2 in both proximity ligation assay and immunocytostaining, and bound with GD2 in immunoprecipitation/TLC immunostaining. Malignant phenotypes of GD2+SCLC cells were enhanced by glutamine uptake, and were suppressed by L‐γ‐glutamyl‐p‐nitroanilide, a specific inhibitor of ASCT2, through reduced phosphorylation of p70 S6K1 and S6. These results suggested that ASCT2 enhances glutamine uptake in glycolipid‐enriched microdomain/rafts in GD2+SCLC cells, leading to the enhancement of cell proliferation and migration through increased phosphorylation of the mTOR complex 1 signaling axis.
Collapse
Affiliation(s)
- Nobutoshi Esaki
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan.,Departments of Biochemistry 2, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuki Ohkawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan
| | - Noboru Hashimoto
- Departments of Biochemistry 2, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuhsuke Tsuda
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan.,Departments of Biochemistry 2, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuhsuke Ohmi
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan
| | - Robiul H Bhuiyan
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan
| | - Norihiro Kotani
- Department of Biochemistry, Saitama Medical University, Moroyama, Japan
| | - Koichi Honke
- Department of Biochemistry, Kochi University School of Medicine, Kochi, Japan
| | - Atsushi Enomoto
- Departments of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahide Takahashi
- Departments of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keiko Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan
| | - Koichi Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Japan
| |
Collapse
|
12
|
Affiliation(s)
- K Motosugi
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu 611, Japan
| | | | | |
Collapse
|
13
|
Hasan AK, Takada H, Esaki N, Soda K. Catalytic action of L-2-halo acid dehalogenase on long-chain L-2-haloalkanoic acids in organic solvents. Biotechnol Bioeng 2009; 38:1114-7. [PMID: 18600877 DOI: 10.1002/bit.260380921] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A Lyophilized preparation of L-2-halo acid dehalogenase was not only stable but also catalytically active in anhydrous dimethyl sulfoxide, toluene, and other organic solvents. 2-Halo acids with long alkyl (C(5)-C(16)) or aromatic (phenyl and benzyl) side chains were inert in water but dehalogenated effectively in anhydrous dimethyl sulfoxide by the lyophilized enzyme. Long chain 2-haloalkanoic acids such as 2-bromohexadecanoic acids were better as substrate than short-chain halo acids (e.g., 2-chloropropanoic acid). The dehalogenation proceed with inversion of C(2) configuration to produce the corresponding (2R)-2-hydroxy acids in anhydrous dimethyl sulfoxide in the same way as found in water.
Collapse
Affiliation(s)
- A K Hasan
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611, Japan
| | | | | | | |
Collapse
|
14
|
Takahata M, Tamura T, Abe K, Mihara H, Kurokawa S, Yamamoto Y, Nakano R, Esaki N, Inagaki K. Selenite Assimilation into Formate Dehydrogenase H Depends on Thioredoxin Reductase in Escherichia coli. J Biochem 2007; 143:467-73. [DOI: 10.1093/jb/mvm247] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
15
|
Omi R, Kurokawa S, Mihara H, Kurihara T, Esaki N, Hirotsu K, Miyahara I. Structural study of selenocysteine lyase. Acta Crystallogr A 2007. [DOI: 10.1107/s0108767307097383] [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
|
16
|
|
17
|
|
18
|
Suzuki T, Nakayama T, Kurihara T, Nishino T, Esaki N. Cold-active lipolytic activity of psychrotrophic Acinetobacter sp. strain no. 6. J Biosci Bioeng 2005; 92:144-8. [PMID: 16233074 DOI: 10.1263/jbb.92.144] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2001] [Accepted: 05/23/2001] [Indexed: 11/17/2022]
Abstract
A lipolytic bacterium, strain no. 6, was isolated from Siberian tundra soil. It was a gram-negative coccoid rod capable of growing at 4 degrees C but not at 37 degrees C and was identified as a psychrotrophic strain of the genus Acinetobacter. Strain no. 6 extracellularly produced a lipolytic enzyme that efficiently hydrolyzed triglycerides such as soybean oil during bacterial growth even at 4 degrees C; it degraded 60% of added soybean oil (initial concentration, 1% w/v) after cultivation in LB medium at 4 degrees C for 7 d. Thus, the bacterium is potentially applicable to in-situ bioremediation or bioaugumentation of fat-contaminated cold environments. We partially purified the lipolytic enzyme from the culture filtrate by acetone fractionation and characterized it. The enzyme preparation contained a single species of cold-active lipase with significant activity at 4 degrees C, which was 57% of the activity at the optimum temperature (20 degrees C). The enzyme showed a broad specificity toward the acyl group (C8-C16) of substrate ethyl esters.
Collapse
Affiliation(s)
- T Suzuki
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | |
Collapse
|
19
|
Yamamoto H, Mitsuhashi K, Kimoto N, Kobayashi Y, Esaki N. Robust NADH-regenerator: improved alpha-haloketone-resistant formate dehydrogenase. Appl Microbiol Biotechnol 2004; 67:33-9. [PMID: 15338080 DOI: 10.1007/s00253-004-1728-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [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: 06/03/2004] [Revised: 07/18/2004] [Accepted: 06/23/2004] [Indexed: 11/30/2022]
Abstract
Formate dehydrogenases (FDH) are useful for the regeneration of NADH, which is required for asymmetric reduction by several dehydrogenases and reductases. FDHs have relatively low activity and are labile, especially to alpha-haloketones, thus FDH cannot be applied to the industrial manufacture of optically active alpha-haloalcohols. To stabilize a FDH from Mycobacterium vaccae (McFDH) against the alpha-haloketone ethyl 4-chloroacetoacetate (ECAA), a set of cysteine-mutant enzymes was constructed. Sensitivity to ECAA of mutant C6S was similar to that of the wild-type enzyme, and mutants C249S and C355S showed little activity. In contrast, mutant C256S exhibited remarkable tolerance to ECAA. Surprisingly, mutant C146S was activated by several organic compounds such as ethyl acetate. An optimized mutant, C6A/C146S/C256V (McFDH-26), was obtained by combining several effective mutations. Ethyl (S)-4-chloro-3-hydroxybutanoate [(S)-ECHB] was synthesized from ECAA to 49.9 g/l with an optical purity of more than 99% e.e. using recombinant Escherichia coli cells coexpressing McFDH-26 and a carbonyl reductase (KaCR1) from Kluyveromyces aestuarii.
Collapse
Affiliation(s)
- H Yamamoto
- Life Science Development Center, CPI Company, Tsukuba Research Center, Daicel Chemical Industries, 27 Miyukigaoka, Tsukuba 305-0841, Japan.
| | | | | | | | | |
Collapse
|
20
|
Abstract
Cysteine desulfurase is a pyridoxal 5'-phosphate (PLP)-dependent homodimeric enzyme that catalyzes the conversion of L-cysteine to L-alanine and sulfane sulfur via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue. Increased evidence for the functions of cysteine desulfurases has revealed their important roles in the biosyntheses of Fe-S clusters, thiamine, thionucleosides in tRNA, biotin, lipoic acid, molybdopterin, and NAD. The enzymes are also proposed to be involved in cellular iron homeostasis and in the biosynthesis of selenoproteins. The mechanisms for sulfur mobilization mediated by cysteine desulfurases are as yet unknown, but enzymes capable of providing a variety of biosynthetic pathways for sulfur/selenium-containing biomolecules are probably applicable to the production of cofactors and the bioconversion of useful compounds.
Collapse
Affiliation(s)
- H Mihara
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | | |
Collapse
|
21
|
Abstract
We have studied the stereospecificities of various pyridoxal 5'-phosphate dependent enzymes for the hydrogen transfer between the C-4' of a bound coenzyme and the C-2 of a substrate in the transamination catalyzed by the enzymes. Prior to our studies, pyridoxal enzymes so far studied were reported to catalyze the hydrogen transfer only on the si-face of the planar imine intermediate formed from substrate and coenzyme. This finding had been considered as the evidence that pyridoxal enzymes have evolved divergently from a common ancestral protein, because identity in the stereospecificity reflects the similarity in the active-site structure, in particular in the geometrical relationship between the coenzyme and the active site base participating in the hydrogen transfer. However, we found that D-amino acid aminotransferase, branched-chain L-amino acid aminotransferase, and 4-amino-4-deoxychorismate lyase catalyze the re-face specific hydrogen transfer, and that amino acid racemases catalyze the nonstereospecific hydrogen transfer. These findings suggest the convergent evolution of pyridoxal enzymes. Crystallographical studies have shown that the stereospecificity reflects the active-site structure of the enzymes, and that the enzymes with the same fold exhibit the same stereospecificity. The active site structure with the catalytic base being situated on the specific face of the cofactor has been conserved during the evolution among the pyridoxal enzymes of the same family.
Collapse
Affiliation(s)
- K Soda
- Department of Biotechnology, Faculty of Engineering, Kansai University, Suita, Osaka 564-8680, Japan.
| | | | | |
Collapse
|
22
|
Lewandowicz A, Sicinska D, Rudzinski J, Ichiyama S, Kurihara T, Esaki N, Paneth P. Chlorine kinetic isotope effect on the fluoroacetate dehalogenase reaction. J Am Chem Soc 2001; 123:9192-3. [PMID: 11552840 DOI: 10.1021/ja0160400] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A Lewandowicz
- Institute of Applied Radiation Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland
| | | | | | | | | | | | | |
Collapse
|
23
|
Uo T, Yoshimura T, Tanaka N, Takegawa K, Esaki N. Functional characterization of alanine racemase from Schizosaccharomyces pombe: a eucaryotic counterpart to bacterial alanine racemase. J Bacteriol 2001; 183:2226-33. [PMID: 11244061 PMCID: PMC95128 DOI: 10.1128/jb.183.7.2226-2233.2001] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Schizosaccharomyces pombe has an open reading frame, which we named alr1(+), encoding a putative protein similar to bacterial alanine racemase. We cloned the alr1(+) gene in Escherichia coli and purified the gene product (Alr1p), with an M(r) of 41,590, to homogeneity. Alr1p contains pyridoxal 5'-phosphate as a coenzyme and catalyzes the racemization of alanine with apparent K(m) and V(max) values as follows: for L-alanine, 5.0 mM and 670 micromol/min/mg, respectively, and for D-alanine, 2.4 mM and 350 micromol/min/mg, respectively. The enzyme is almost specific to alanine, but L-serine and L-2-aminobutyrate are racemized slowly at rates 3.7 and 0.37% of that of L-alanine, respectively. S. pombe uses D-alanine as a sole nitrogen source, but deletion of the alr1(+) gene resulted in retarded growth on the same medium. This indicates that S. pombe has catabolic pathways for both enantiomers of alanine and that the pathway for L-alanine coupled with racemization plays a major role in the catabolism of D-alanine. Saccharomyces cerevisiae differs markedly from S. pombe: S. cerevisiae uses L-alanine but not D-alanine as a sole nitrogen source. Moreover, D-alanine is toxic to S. cerevisiae. However, heterologous expression of the alr1(+) gene enabled S. cerevisiae to grow efficiently on D-alanine as a sole nitrogen source. The recombinant yeast was relieved from the toxicity of D-alanine.
Collapse
Affiliation(s)
- T Uo
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | |
Collapse
|
24
|
Abstract
In order to develop a biological process for removal of selenium from industrial wastewater, Bacillus sp. strain SF-1 was isolated from selenium-contaminated sediment. The bacterium reduces selenate to selenite and subsequently to nontoxic insoluble elemental selenium using lactate as an electron donor and selenate as an electron acceptor in an anaerobic condition. Elemental selenium transformed from soluble selenium was deposited both inside and outside of the cells. Since the selenate reduction rate of the strain SF-1 was higher than the selenite reduction rate, selenite was transiently accumulated. In an experiment of the repeated soluble selenium reduction by strain SF-1, 0.5 mM of selenate was sequentially treatable with a cycle of one day. Thus, our sequential system for removal of soluble selenium is very useful.
Collapse
Affiliation(s)
- M Kashiwa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | |
Collapse
|
25
|
Ichiyama S, Kurihara T, Li YF, Kogure Y, Tsunasawa S, Esaki N. Novel catalytic mechanism of nucleophilic substitution by asparagine residue involving cyanoalanine intermediate revealed by mass spectrometric monitoring of an enzyme reaction. J Biol Chem 2000; 275:40804-9. [PMID: 11006296 DOI: 10.1074/jbc.m008065200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [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: 11/06/2022] Open
Abstract
l-2-Haloacid dehalogenase from Pseudomonas sp. YL catalyzes the hydrolytic dehalogenation, in which Asp(10) acts as a nucleophile to attack the alpha-carbon of l-2-haloalkanoates to form an ester intermediate, which is subsequently hydrolyzed to produce d-2-hydroxyalkanoates. Surprisingly, replacement of the catalytic residue, Asp(10), by Asn did not result in total inactivation of the enzyme (Kurihara, T., Liu, J.-Q., Nardi-Dei, V., Koshikawa, H., Esaki, N., and Soda, K. (1995) J. Biochem. 117, 1317-1322). In this study, we monitored the D10N mutant enzyme reaction by ion-spray mass spectrometry, and found that the enzyme shows a unique structural change when it was incubated with the substrate, l-2-chloropropionate. LC/MS and tandem MS/MS analyses revealed that Asn(10) attacks the substrate to form an imidate, and a proton and d-lactic acid are eliminated to produce a nitrile (beta-cyanoalanine residue), followed by hydrolysis to reproduce Asn(10). This is the first report of the function of Asn to catalyze nucleophilic substitution through its conversion to beta-cyanoalanine residue as an intermediate structure. Also, these results demonstrate that mass spectrometry is remarkably useful in monitoring enzyme reactions.
Collapse
Affiliation(s)
- S Ichiyama
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | |
Collapse
|
26
|
Gutierrez A, Yoshimura T, Fuchikami Y, Esaki N. Modulation of activity and substrate specificity by modifying the backbone length of the distant interdomain loop of D-amino acid aminotransferase. Eur J Biochem 2000; 267:7218-23. [PMID: 11106434 DOI: 10.1046/j.1432-1327.2000.01833.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The activity and substrate specificity of D-amino acid aminotransferase (D-AAT) (EC 2.6.1.21) can be rationally modulated by replacing the loop core (P119-R120-P121) with glycine chains of different lengths: 1, 3, or 5 glycines. The mutant enzymes were much more active than the wild-type enzyme in the overall reactions between various amino acids and pyruvate. The presteady-state kinetic analyses of half-reactions revealed that the 5-glycine mutant has the highest affinity (Kd) among all mutant enzymes and the wild-type enzyme towards various amino acids except D-aspartate. The 5-glycine mutant was much more efficient as a catalyst than the wild-type enzyme because the mutant enzyme showed the highest value of specificity constant (kmax/Kd) for all amino acids except D-aspartate and D-glutamate. The kmax/Kd values of the three mutants decreased with decrease in glycine chain length for each amino acid examined. Our findings may provide a new approach to rational modulation of enzymes.
Collapse
Affiliation(s)
- A Gutierrez
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu, Japan
| | | | | | | |
Collapse
|
27
|
Okubo Y, Yokoigawa K, Esaki N, Soda K, Misono H. High catalytic activity of alanine racemase from psychrophilic Bacillus psychrosaccharolyticus at high temperatures in the presence of pyridoxal 5'-phosphate. FEMS Microbiol Lett 2000; 192:169-73. [PMID: 11064190 DOI: 10.1111/j.1574-6968.2000.tb09377.x] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We examined the effect of the pyridoxal 5'-phosphate (PLP) cofactor on the activity and stability of the psychrophilic alanine racemase, having a high catalytic activity at low temperature, from Bacillus psychrosaccharolyticus at high temperatures. The decrease in the enzyme activity at incubation temperatures over 40 degrees C was consistent with the decrease in the amount of bound PLP. Unfolding of the enzyme at temperatures above 40 degrees C was suppressed in the presence of PLP. In the presence of 0.125 mM PLP, the specific activity of the psychrophilic enzyme was higher than that of a thermophilic alanine racemase, having a high catalytic activity at high temperature, from Bacillus stearothermophilus even at 60 degrees C.
Collapse
Affiliation(s)
- Y Okubo
- Research Institute of Molecular Genetics, Kochi University, Nankoku, Kochi, Japan.
| | | | | | | | | |
Collapse
|
28
|
Inoue H, Inagaki K, Adachi N, Tamura T, Esaki N, Soda K, Tanaka H. Role of tyrosine 114 of L-methionine gamma-lyase from Pseudomonas putida. Biosci Biotechnol Biochem 2000; 64:2336-43. [PMID: 11193400 DOI: 10.1271/bbb.64.2336] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
L-Methionine gamma-lyase from Pseudomonas putida has a conserved tyrosine residue (Tyr114) in the active site as in all known sequences of y-family pyridoxal 5'-phosphate dependent enzymes. A mutant form of L-methionine y-lyase in which Tyr114 was replaced by phenylalanine (Y114F) resulted in 910-fold decrease in kcat for alpha,gamma-elimination of L-methionine, while the Km remained the same as the wild type enzyme. The Y114F mutant had the reduced kcat by only 28- and 16-fold for substrates with an electron-withdrawing group at the gamma-position, namely O-acetyl-L-homoserine and L-methionine sulfone, respectively, and also the similar reduction of kcat for alpha,beta-elimination and deamination substrates. The hydrogen exchange reactions of substrate and the spectral changes of the substrate-enzyme complex catalyzed by the mutant enzyme suggested that gamma-elimination process for L-methionine is the rate-limiting determination step in alpha,gamma-elimination overall reaction of the Y114F mutant. These results indicate that Tyr114 of L-methionine gamma-lyase is important in y-elimination of the substrate.
Collapse
Affiliation(s)
- H Inoue
- Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University, Japan
| | | | | | | | | | | | | |
Collapse
|
29
|
Kato S, Mihara H, Kurihara T, Yoshimura T, Esaki N. Gene cloning, purification, and characterization of two cyanobacterial NifS homologs driving iron-sulfur cluster formation. Biosci Biotechnol Biochem 2000; 64:2412-9. [PMID: 11193410 DOI: 10.1271/bbb.64.2412] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [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: 11/08/2022]
Abstract
Iron-sulfur proteins are essential in the photosynthetic system and many other biological processes. We have isolated and characterized enzymes driving the formation of iron-sulfur clusters from Synechocystis sp. PCC6803. Two genes (slr0387 and sll0704), showing similarity to nifS of Azotobacter vinelandii, were cloned, and their gene products (SsCsdl and SsCsd2) were purified. They catalyzed the desulfuration of L-cysteine. Reconstitution of a [2Fe-2S] cluster of cyanobacterial ferredoxin proceeded much faster in the presence of L-cysteine and either of these enzymes than when using sodium sulfide. These results suggest that SsCsdl and SsCsd2 facilitate the iron-sulfur cluster assembly by producing inorganic sulfur from L-cysteine. Synechocystis sp. PCC6803 has no gene coding for a protein with similarity to the N-terminal domain of NifU of A. vinelandii, which is believed to cooperate with NifS to assemble iron-sulfur clusters. Thus, the cluster formation in the cyanobacterium probably proceeds through a mechanism that is different from that in A. vinelandii.
Collapse
Affiliation(s)
- S Kato
- Institute for Chemical Research, Kyoto University, Japan
| | | | | | | | | |
Collapse
|
30
|
Jhee KH, Yoshimura T, Miles EW, Takeda S, Miyahara I, Hirotsu K, Soda K, Kawata Y, Esaki N. Stereochemistry of the transamination reaction catalyzed by aminodeoxychorismate lyase from Escherichia coli: close relationship between fold type and stereochemistry. J Biochem 2000; 128:679-86. [PMID: 11011151 DOI: 10.1093/oxfordjournals.jbchem.a022801] [Citation(s) in RCA: 11] [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] [Indexed: 11/12/2022] Open
Abstract
Aminodeoxychorismate lyase is a pyridoxal 5'-phosphate-dependent enzyme that converts 4-aminodeoxychorismate to pyruvate and p-aminobenzoate, a precursor of folic acid in bacteria. The enzyme exhibits significant sequence similarity to two aminotransferases, D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase. In the present study, we have found that aminodeoxychorismate lyase catalyzes the transamination between D-alanine and pyridoxal phosphate to produce pyruvate and pyridoxamine phosphate. L-Alanine and other D- and L-amino acids tested were inert as substrates of transamination. The pro-R hydrogen of C4' of pyridoxamine phosphate was stereospecifically abstracted during the reverse half transamination from pyridoxamine phosphate to pyruvate. Aminodeoxychorismate lyase is identical to D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase in the stereospecificity of the hydrogen abstraction, and differs from all other pyridoxal enzymes that catalyze pro-S hydrogen transfer. Aminodeoxychorismate lyase is the first example of a lyase that catalyzes pro-R-specific hydrogen abstraction. The result is consistent with recent X-ray crystallographic findings showing that the topological relationships between the cofactor and the catalytic residue for hydrogen abstraction are conserved among aminodeoxychorismate lyase, D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase [Nakai, T., Mizutani, H., Miyahara, I., Hirotsu, K., Takeda, S., Jhee, K.-H., Yoshimura, T., and Esaki, N. (2000) J. Biochem. 128, 29-38].
Collapse
Affiliation(s)
- K H Jhee
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Kurihara T, Esaki N. [Biogenesis of iron-sulfur clusters]. Seikagaku 2000; 72:1266-9. [PMID: 11215150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- T Kurihara
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011
| | | |
Collapse
|
32
|
Motoshima H, Inagaki K, Kumasaka T, Furuichi M, Inoue H, Tamura T, Esaki N, Soda K, Tanaka N, Yamamoto M, Tanaka H. Crystal structure of the pyridoxal 5'-phosphate dependent L-methionine gamma-lyase from Pseudomonas putida. J Biochem 2000; 128:349-54. [PMID: 10965031 DOI: 10.1093/oxfordjournals.jbchem.a022760] [Citation(s) in RCA: 39] [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] [Indexed: 11/14/2022] Open
Abstract
L-Methionine gamma-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) dependent alpha,gamma-elimination of L-methionine. We have determined two crystal structures of MGL from Pseudomonas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures have been refined to an R-factor of 21.1% at 2.0 and 1.7 A resolution using synchrotron radiation diffraction data. A homotetramer with 222 symmetry is built up by non-crystallographic symmetry. Two monomers associate to build the active dimer. The spatial fold of subunits, with three functionally distinct domains and their quarternary arrangement, is similar to those of L-cystathionine beta-lyase and L-cystathionine gamma-synthase from Escherichia coli.
Collapse
Affiliation(s)
- H Motoshima
- RIKEN Harima Institute, Kouto, Mikazuki, Sayo-gun, Hyogo 679-5148, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Lacourciere GM, Mihara H, Kurihara T, Esaki N, Stadtman TC. Escherichia coli NifS-like proteins provide selenium in the pathway for the biosynthesis of selenophosphate. J Biol Chem 2000; 275:23769-73. [PMID: 10829016 DOI: 10.1074/jbc.m000926200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [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: 11/06/2022] Open
Abstract
Selenophosphate synthetase (SPS), the selD gene product from Escherichia coli, catalyzes the biosynthesis of monoselenophosphate, AMP, and orthophosphate in a 1:1:1 ratio from selenide and ATP. Kinetic characterization revealed the K(m) value for selenide approached levels that are toxic to the cell. Our previous demonstration that a Se(0)-generating system consisting of l-selenocysteine and the Azotobacter vinelandii NifS protein can replace selenide for selenophosphate biosynthesis in vitro suggested a mechanism whereby cells can overcome selenide toxicity. Recently, three E. coli NifS-like proteins, CsdB, CSD, and IscS, have been overexpressed and characterized. All three enzymes act on selenocysteine and cysteine to produce Se(0) and S(0), respectively. In the present study, we demonstrate the ability of each E. coli NifS-like protein to function as a selenium delivery protein for the in vitro biosynthesis of selenophosphate by E. coli wild-type SPS. Significantly, the SPS (C17S) mutant, which is inactive in the standard in vitro assay with selenide as substrate, was found to exhibit detectable activity in the presence of CsdB, CSD, or IscS and l-selenocysteine. Taken together the ability of the NifS-like proteins to generate a selenium substrate for SPS and the activation of the SPS (C17S) mutant suggest a selenium delivery function for the proteins in vivo.
Collapse
Affiliation(s)
- G M Lacourciere
- Laboratory of Biochemistry, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA.
| | | | | | | | | |
Collapse
|
34
|
Nakai T, Mizutani H, Miyahara I, Hirotsu K, Takeda S, Jhee KH, Yoshimura T, Esaki N. Three-dimensional structure of 4-amino-4-deoxychorismate lyase from Escherichia coli. J Biochem 2000; 128:29-38. [PMID: 10876155 DOI: 10.1093/oxfordjournals.jbchem.a022727] [Citation(s) in RCA: 39] [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] [Indexed: 11/14/2022] Open
Abstract
4-Amino-4-deoxychorismate lyase (ADCL) is a member of the fold-type IV of PLP dependent enzymes that converts 4-amino-4-deoxychorismate (ADC) to p-aminobenzoate and pyruvate. The crystal structure of ADCL from Escherichia coli has been solved using MIR phases in combination with density modification. The structure has been refined to an R-factor of 20.6% at 2.2 A resolution. The enzyme is a homo dimer with a crystallographic twofold axis, and the polypeptide chain is folded into small and large domains with an interdomain loop. The coenzyme, pyridoxal 5'-phosphate, resides at the domain interface, its re-face facing toward the protein. Although the main chain folding of the active site is homologous to those of D-amino acid and L-branched-chain amino acid aminotransferases, no residues in the active site are conserved among them except for Arg59, Lys159, and Glu193, which directly interact with the coenzyme and play critical roles in the catalytic functions. ADC was modeled into the active site of the unliganded enzyme on the basis of the X-ray structures of the unliganded and liganded forms in the D-amino acid and L-branched-chain amino acid aminotransferases. According to this model, the carboxylates of ADC are recognized by Asn256, Arg107, and Lys97, and the cyclohexadiene moiety makes van der Waals contact with the side chain of Leu258. ADC forms a Schiff base with PLP to release the catalytic residue Lys159, which forms a hydrogen bond with Thr38. The neutral amino group of Lys159 eliminates the a-proton of ADC to give a quinonoid intermediate to release a pyruvate in accord with the proton transfer from Thr38 to the olefin moiety of ADC.
Collapse
Affiliation(s)
- T Nakai
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Mihara H, Kurihara T, Yoshimura T, Esaki N. Kinetic and mutational studies of three NifS homologs from Escherichia coli: mechanistic difference between L-cysteine desulfurase and L-selenocysteine lyase reactions. J Biochem 2000; 127:559-67. [PMID: 10739946 DOI: 10.1093/oxfordjournals.jbchem.a022641] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [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: 11/12/2022] Open
Abstract
We have purified three NifS homologs from Escherichia coli, CSD, CsdB, and IscS, that appear to be involved in iron-sulfur cluster formation and/or the biosynthesis of selenophosphate. All three homologs catalyze the elimination of Se and S from L-selenocysteine and L-cysteine, respectively, to form L-alanine. These pyridoxal 5'-phosphate enzymes were inactivated by abortive transamination, yielding pyruvate and a pyridoxamine 5'-phosphate form of the enzyme. The enzymes showed non-Michaelis-Menten behavior for L-selenocysteine and L-cysteine. When pyruvate was added, they showed Michaelis-Menten behavior for L-selenocysteine but not for L-cysteine. Pyruvate significantly enhanced the activity of CSD toward L-selenocysteine. Surprisingly, the enzyme activity toward L-cysteine was not increased as much by pyruvate, suggesting the presence of different rate-limiting steps or reaction mechanisms for L-cysteine desulfurization and the degradation of L-selenocysteine. We substituted Ala for each of Cys358 in CSD, Cys364 in CsdB, and Cys328 in IscS, residues that correspond to the catalytically essential Cys325 of Azotobacter vinelandii NifS. The enzyme activity toward L-cysteine was almost completely abolished by the mutations, whereas the activity toward L-selenocysteine was much less affected. This indicates that the reaction mechanism of L-cysteine desulfurization is different from that of L-selenocysteine decomposition, and that the conserved cysteine residues play a critical role only in L-cysteine desulfurization.
Collapse
Affiliation(s)
- H Mihara
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | | | | | | |
Collapse
|
36
|
Mihara H, Kurihara T, Watanabe T, Yoshimura T, Esaki N. cDNA cloning, purification, and characterization of mouse liver selenocysteine lyase. Candidate for selenium delivery protein in selenoprotein synthesis. J Biol Chem 2000; 275:6195-200. [PMID: 10692412 DOI: 10.1074/jbc.275.9.6195] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [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: 11/06/2022] Open
Abstract
Selenocysteine lyase (SCL) (EC 4.4.1.16) is a pyridoxal 5'-phosphate-dependent enzyme that specifically catalyzes the decomposition of L-selenocysteine to L-alanine and elemental selenium. The enzyme was proposed to function as a selenium delivery protein to selenophosphate synthetase in selenoprotein biosynthesis (Lacourciere, G. M., and Stadtman, T. C. (1998) J. Biol. Chem. 273, 30921-30926). We purified SCL from pig liver and determined its partial amino acid sequences. Mouse cDNA clones encoding peptides resembling pig SCL were found in the expressed sequence tag data base, and their sequences were used as probes to isolate full-length mouse liver cDNA. The cDNA for mouse SCL (mSCL) was determined to be 2,172 base pairs in length, containing an open reading frame encoding a polypeptide chain of 432 amino acid residues (M(r) 47, 201). We also determined the sequence of the N-terminal region of putative human SCL. These enzymes were shown to be distantly related in primary structure to NifS, which catalyzes the desulfurization of L-cysteine to provide sulfur for iron-sulfur clusters. The recombinant mSCL overproduced in Escherichia coli was a homodimer with the subunit M(r) of 47,000. The enzyme was pyridoxal phosphate-dependent and highly specific to L-selenocysteine (the k(cat)/K(m) value for L-selenocysteine was about 4,200 times higher than that for L-cysteine). Reverse transcriptase-polymerase chain reaction and Western blot analyses revealed that mSCL is cytosolic and predominantly exists in the liver, kidney, and testis, where mouse selenophosphate synthetase is also abundant, supporting the view that mSCL functions in cooperation with selenophosphate synthetase in selenoprotein synthesis. This is the first report of the primary structure of mammalian SCL.
Collapse
Affiliation(s)
- H Mihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | |
Collapse
|
37
|
Fujii T, Maeda M, Mihara H, Kurihara T, Esaki N, Hata Y. Structure of a NifS homologue: X-ray structure analysis of CsdB, an Escherichia coli counterpart of mammalian selenocysteine lyase. Biochemistry 2000; 39:1263-73. [PMID: 10684605 DOI: 10.1021/bi991732a] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [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: 11/28/2022]
Abstract
Escherichia coli CsdB, a NifS homologue with a high specificity for L-selenocysteine, is a pyridoxal 5'-phosphate (PLP)-dependent dimeric enzyme that belongs to aminotransferases class V in fold-type I of PLP enzymes and catalyzes the decomposition of L-selenocysteine into selenium and L-alanine. The crystal structure of the enzyme has been determined by the X-ray crystallographic method of multiple isomorphous replacement and refined to an R-factor of 18.7% at 2.8 A resolution. The subunit structure consists of three parts: a large domain of an alpha/beta-fold containing a seven-stranded beta-sheet flanked by seven helices, a small domain containing a four-stranded antiparallel beta-sheet flanked by three alpha-helices, and an N-terminal segment containing two alpha-helices. The overall fold of the subunit is similar to those of the enzymes belonging to the fold-type I family represented by aspartate aminotransferase. However, CsdB has several structural features that are not observed in other families of the enzymes. A remarkable feature is that an alpha-helix in the lobe extending from the small domain to the large domain in one subunit of the dimer interacts with a beta-hairpin loop protruding from the large domain of the other subunit. The extended lobe and the protruded beta-hairpin loop form one side of a limb of each active site in the enzyme. The most striking structural feature of CsdB lies in the location of a putative catalytic residue; the side chain of Cys364 on the extended lobe of one subunit is close enough to interact with the gamma-atom of a modeled substrate in the active site of the subunit. Moreover, His55 from the other subunit is positioned so that it interacts with the gamma- or beta-atom of the substrate and may be involved in the catalytic reaction. This is the first report on three-dimensional structures of NifS homologues.
Collapse
Affiliation(s)
- T Fujii
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | |
Collapse
|
38
|
Takita T, Shimizu N, Sukata T, Hashimoto S, Akita E, Yokota T, Esaki N, Soda K, Inouye K, Tonomura B. Lysyl-tRNA synthetase of Bacillus stearothermophilus molecular cloning and expression of the gene. Biosci Biotechnol Biochem 2000; 64:432-7. [PMID: 10737207 DOI: 10.1271/bbb.64.432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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: 11/08/2022]
Abstract
The gene of the lysyl-tRNA synthetase of Bacillus stearothermophilus NCA1503 was cloned and sequenced. The gene consists of 1485 bp nucleotides commencing with an ATG start codon and ending with a TAA stop codon, and encodes a polypeptide of 493 amino acids. The recombinant enzymes were expressed in E. coli using an expression plasmid containing the T7 RNA polymerase/promoter.
Collapse
Affiliation(s)
- T Takita
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Watanabe A, Yoshimura T, Mikami B, Esaki N. Tyrosine 265 of alanine racemase serves as a base abstracting alpha-hydrogen from L-alanine: the counterpart residue to lysine 39 specific to D-alanine. J Biochem 1999; 126:781-6. [PMID: 10502689 DOI: 10.1093/oxfordjournals.jbchem.a022517] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alanine racemase of Bacillus stearothermophilus has been proposed to catalyze alanine racemization by means of two catalytic bases: lysine 39 (K39) abstracting specifically the alpha-hydrogen of D-alanine and tyrosine 265 (Y265) playing the corresponding role for the antipode L-alanine. The role of K39 as indicated has already been verified [Watanabe, A., Kurokawa, Y., Yoshimura, T., Kurihara, T., Soda, K., and Esaki, N. (1999) J. Biol. Chem. 274, 4189-4194]. We here present evidence for the functioning of Y265 as the base catalyst specific to L-alanine. The Y265-->Ala mutant enzyme (Y265A), like Y265S and Y265F, was a poor catalyst for alanine racemization. However, Y265A and Y265S catalyzed transamination with D-alanine much more rapidly than the wild-type enzyme, and the bound coenzyme, pyridoxal 5'-phosphate (PLP), was converted to pyridoxamine 5'-phosphate (PMP). The rate of transamination catalyzed by Y265F was about 9% of that by the wild-type enzyme. However, Y265A, Y265S, and Y265F were similar in that L-alanine was inert as a substrate in transamination. The apo-form of the wild-type enzyme catalyzes the abstraction of tritium non-specifically from both (4'S)- and (4'R)-[4'-(3)H]PMP in the presence of pyruvate. In contrast, apo-Y265A abstracts tritium virtually from only the R-isomer. This indicates that the side-chain of Y265 abstracts the alpha-hydrogen of L-alanine and transfers it supra-facially to the pro-S position at C-4' of PMP. Y265 is the counterpart residue to K39 that transfers the alpha-hydrogen of D-alanine to the pro-R position of PMP.
Collapse
Affiliation(s)
- A Watanabe
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | | | | | | |
Collapse
|
40
|
Galkin A, Kulakova L, Ashida H, Sawa Y, Esaki N. Cold-adapted alanine dehydrogenases from two antarctic bacterial strains: gene cloning, protein characterization, and comparison with mesophilic and thermophilic counterparts. Appl Environ Microbiol 1999; 65:4014-20. [PMID: 10473410 PMCID: PMC99735 DOI: 10.1128/aem.65.9.4014-4020.1999] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [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
The genes encoding NAD(+)-dependent alanine dehydrogenases (AlaDHs) (EC 1.4.1.1) from the Antarctic bacterial organisms Shewanella sp. strain Ac10 (SheAlaDH) and Carnobacterium sp. strain St2 (CarAlaDH) were cloned and expressed in Escherichia coli. Of all of the AlaDHs that have been sequenced, SheAlaDH exhibited the highest level of sequence similarity to the AlaDH from the gram-negative bacterium Vibrio proteolyticus (VprAlaDH). CarAlaDH was most similar to AlaDHs from mesophilic and thermophilic Bacillus strains. SheAlaDH and CarAlaDH had features typical of cold-adapted enzymes; both the optimal temperature for catalytic activity and the temperature limit for retaining thermostability were lower than the values obtained for the mesophilic counterparts. The k(cat)/K(m) value for the SheAlaDH reaction was about three times higher than the k(cat)/K(m) value for VprAlaDH, but it was much lower than the k(cat)/K(m) value for the AlaDH from Bacillus subtilis. Homology-based structural models of various AlaDHs, including the two psychotropic AlaDHs, were constructed. The thermal instability of SheAlaDH and CarAlaDH may result from relatively low numbers of salt bridges in these proteins.
Collapse
Affiliation(s)
- A Galkin
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu 611, Japan
| | | | | | | | | |
Collapse
|
41
|
Nardi-Dei V, Kurihara T, Park C, Miyagi M, Tsunasawa S, Soda K, Esaki N. DL-2-Haloacid dehalogenase from Pseudomonas sp. 113 is a new class of dehalogenase catalyzing hydrolytic dehalogenation not involving enzyme-substrate ester intermediate. J Biol Chem 1999; 274:20977-81. [PMID: 10409645 DOI: 10.1074/jbc.274.30.20977] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [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: 11/06/2022] Open
Abstract
DL-2-Haloacid dehalogenase from Pseudomonas sp. 113 (DL-DEX 113) catalyzes the hydrolytic dehalogenation of D- and L-2-haloalkanoic acids, producing the corresponding L- and D-2-hydroxyalkanoic acids, respectively. Every halidohydrolase studied so far (L-2-haloacid dehalogenase, haloalkane dehalogenase, and 4-chlorobenzoyl-CoA dehalogenase) has an active site carboxylate group that attacks the substrate carbon atom bound to the halogen atom, leading to the formation of an ester intermediate. This is subsequently hydrolyzed, resulting in the incorporation of an oxygen atom of the solvent water molecule into the carboxylate group of the enzyme. In the present study, we analyzed the reaction mechanism of DL-DEX 113. When a single turnover reaction of DL-DEX 113 was carried out with a large excess of the enzyme in H(2)(18)O with a 10 times smaller amount of the substrate, either D- or L-2-chloropropionate, the major product was found to be (18)O-labeled lactate by ionspray mass spectrometry. After a multiple turnover reaction in H(2)(18)O, the enzyme was digested with trypsin or lysyl endopeptidase, and the molecular masses of the peptide fragments were measured with an ionspray mass spectrometer. No peptide fragments contained (18)O. These results indicate that the H(2)(18)O of the solvent directly attacks the alpha-carbon of 2-haloalkanoic acid to displace the halogen atom. This is the first example of an enzymatic hydrolytic dehalogenation that proceeds without producing an ester intermediate.
Collapse
Affiliation(s)
- V Nardi-Dei
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
Tyrosine 265 (Y265) of Bacillus stearothermophilus is believed to serve as a catalytic base specific to the L-enantiomer of a substrate amino acid by removing (or returning) an alpha-hydrogen from (or to) the isomer on the basis of the X-ray structure of the enzyme [Stamper, C.G., Morollo, A.A., and Ringe, D. (1998) Biochemistry 37, 10438-10443]. We found that the Y265-->Ala mutant (Y265A) enzyme is virtually inactive as a catalyst for alanine racemization. We examined the role of Y265 further with beta-chloroalanine as a substrate with the expectation that the Y265A mutant only catalyzes the alpha,beta-elimination of the D-enantiomer of beta-chloroalanine. However, L-beta-chloroalanine also served as a substrate; this enantiomer was rather better as a substrate than its antipode. Moreover, the mutant enzyme was as equally active as the wild-type enzyme in the elimination reaction. These findings indicate that Y265 is essential for alanine racemization but not for beta-chloroalanine elimination.
Collapse
Affiliation(s)
- A Watanabe
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | | | | | | |
Collapse
|
43
|
Kawata Y, Tamura K, Yano S, Mizobata T, Nagai J, Esaki N, Soda K, Tokushige M, Yumoto N. Purification and characterization of thermostable aspartase from Bacillus sp. YM55-1. Arch Biochem Biophys 1999; 366:40-6. [PMID: 10334861 DOI: 10.1006/abbi.1999.1186] [Citation(s) in RCA: 22] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A thermostable aspartase was purified from a thermophile Bacillus sp. YM55-1 and characterized in terms of activity and stability. The enzyme was isolated by a 5-min heat treatment at 75 degrees C in the presence of 11% (w/v) ammonium sulfate and 100 mM aspartate, followed by Q-Sepharose anion-exchange and AF-Red Toyopearl chromatographies. The native molecular weight of aspartase determined by gel filtration was about 200,000, and this enzyme was composed of four identical monomers with molecular weights of 51,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Unlike Escherichia coli aspartase, the enzyme was not activated by the presence of magnesium ion at alkaline pH. At the optimum pH, the Km and Vmax were 28.5 mM and 700 units/mg at 30 degrees C and 32.0 mM and 2200 units/mg at 55 degrees C, respectively. The specific activity was four and three times higher than those of E. coli and Pseudomonas fluorescens enzymes at 30 degrees C, respectively. Eighty percent of the activity was retained after a 60-min incubation at 55 degrees C, and the enzyme was also resistant to chemical denaturants; 80% of the initial specific activity was detected in assay mixtures containing 1.0 M guanidine hydrochloride. The purified enzyme shared a high sequence homology in the N-terminal region with aspartases from other organisms.
Collapse
Affiliation(s)
- Y Kawata
- Faculty of Engineering, Tottori University, Tottori, 680-0945, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Mihara H, Maeda M, Fujii T, Kurihara T, Hata Y, Esaki N. A nifS-like gene, csdB, encodes an Escherichia coli counterpart of mammalian selenocysteine lyase. Gene cloning, purification, characterization and preliminary x-ray crystallographic studies. J Biol Chem 1999; 274:14768-72. [PMID: 10329673 DOI: 10.1074/jbc.274.21.14768] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [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: 11/06/2022] Open
Abstract
Selenocysteine lyase is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the exclusive decomposition of L-selenocysteine to L-alanine and elemental selenium. An open reading frame, named csdB, from Escherichia coli encodes a putative protein that is similar to selenocysteine lyase of pig liver and cysteine desulfurase (NifS) of Azotobacter vinelandii. In this study, the csdB gene was cloned and expressed in E. coli cells. The gene product was a homodimer with the subunit Mr of 44,439, contained 1 mol of PLP as a cofactor per mol of subunit, and catalyzed the release of Se, SO2, and S from L-selenocysteine, L-cysteine sulfinic acid, and L-cysteine, respectively, to yield L-alanine; the reactivity of the substrates decreased in this order. Although the enzyme was not specific for L-selenocysteine, the high specific activity for L-selenocysteine (5.5 units/mg compared with 0.019 units/mg for L-cysteine) supports the view that the enzyme can be regarded as an E. coli counterpart of mammalian selenocysteine lyase. We crystallized CsdB, the csdB gene product, by the hanging drop vapor diffusion method. The crystals were of suitable quality for x-ray crystallography and belonged to the tetragonal space group P43212 with unit cell dimensions of a = b = 128.1 A and c = 137.0 A. Consideration of the Matthews parameter Vm (3.19 A3/Da) accounts for the presence of a single dimer in the crystallographic asymmetric unit. A native diffraction dataset up to 2.8 A resolution was collected. This is the first crystallographic analysis of a protein of NifS/selenocysteine lyase family.
Collapse
Affiliation(s)
- H Mihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | |
Collapse
|
45
|
Okubo Y, Yokoigawa K, Esaki N, Soda K, Kawai H. Characterization of psychrophilic alanine racemase from Bacillus psychrosaccharolyticus. Biochem Biophys Res Commun 1999; 256:333-40. [PMID: 10080917 DOI: 10.1006/bbrc.1999.0324] [Citation(s) in RCA: 39] [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] [Indexed: 11/22/2022]
Abstract
A psychrophilic alanine racemase gene from Bacillus psychrosaccharolyticus was cloned and expressed in Escherichia coli SOLR with a plasmid pYOK3. The gene starting with the unusual initiation codon GTG showed higher preference for codons ending in A or T. The enzyme purified to homogeneity showed the high catalytic activity even at 0 degrees C and was extremely labile over 35 degrees C. The enzyme was found to have a markedly large Km value (5.0 microM) for the pyridoxal 5'-phosphate (PLP) cofactor in comparison with other reported alanine racemases, and was stabilized up to 50 degrees C in the presence of excess amounts of PLP. The low affinity of the enzyme for PLP may be related to the thermolability, and may be related to the high catalytic activity, initiated by the transaldimination reaction, at low temperature. The enzyme has a distinguishing hydrophilic region around the residue no. 150 in the deduced amino acid sequence (383 residues), whereas the corresponding regions of other Bacillus alanine racemases are hydrophobic. The position of the region in the three dimensional structure of C atoms of the enzyme was predicted to be in a surface loop surrounding the active site. The region may interact with solvent and reduce the compactness of the active site.
Collapse
Affiliation(s)
- Y Okubo
- Department of Food Science and Nutrition, Nara Women's Hospital, Nara, Japan
| | | | | | | | | |
Collapse
|
46
|
Watanabe A, Kurokawa Y, Yoshimura T, Kurihara T, Soda K, Esaki N, Watababe A. Role of lysine 39 of alanine racemase from Bacillus stearothermophilus that binds pyridoxal 5'-phosphate. Chemical rescue studies of Lys39 --> Ala mutant. J Biol Chem 1999; 274:4189-94. [PMID: 9933615 DOI: 10.1074/jbc.274.7.4189] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lysine residue binding with the cofactor pyridoxal 5'-phosphate (PLP) plays an important role in catalysis, such as in the transaldimination and abstraction of alpha-hydrogen from a substrate amino acid in PLP-dependent enzymes. We studied the role of Lys39 of alanine racemase (EC 5.1.1.1) from Bacillus stearothermophilus, the PLP-binding residue of the enzyme, by replacing it site-specifically with alanine and characterizing the resultant K39A mutant enzyme. The mutant enzyme turned out to be inherently inactive, but gained an activity as high as about 0.1% of that of the wild-type enzyme upon addition of 0.2 M methylamine. The amine-assisted activity of the mutant enzyme depended on the pKa values and molecular volumes of the alkylamines used. A strong kinetic isotope effect was observed when alpha-deuterated D-alanine was used as a substrate in the methylamine-assisted reaction, but little effect was observed using its antipode. In marked contrast, only L-enantiomer of alanine showed a solvent isotope effect in deuterium oxide in the methylamine-assisted reaction. These results suggest that methylamine serves as a base not only to abstract the alpha-hydrogen from D-alanine but also to transfer a proton from water to the alpha-position of the deprotonated (achiral) intermediate to form D-alanine. Therefore, the exogenous amine can be regarded as a functional group fully representing Lys39 of the wild-type enzyme. Lys39 of the wild-type enzyme probably acts as the base catalyst specific to the D-enantiomer of alanine. Another residue specific to the L-enantiomer in the wild-type enzyme is kept intact in the K39A mutant.
Collapse
Affiliation(s)
- A Watanabe
- Laboratory of Biofunctional Molecules, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | | | |
Collapse
|
47
|
Kulakova L, Galkin A, Kurihara T, Yoshimura T, Esaki N. Cold-active serine alkaline protease from the psychrotrophic bacterium Shewanella strain ac10: gene cloning and enzyme purification and characterization. Appl Environ Microbiol 1999; 65:611-7. [PMID: 9925590 PMCID: PMC91069 DOI: 10.1128/aem.65.2.611-617.1999] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding serine alkaline protease (SapSh) of the psychrotrophic bacterium Shewanella strain Ac10 was cloned in Escherichia coli. The amino acid sequence deduced from the 2,442-bp nucleotide sequence revealed that the protein was 814 amino acids long and had an estimated molecular weight of 85,113. SapSh exhibited sequence similarities with members of the subtilisin family of proteases, and there was a high level of conservation in the regions around a putative catalytic triad consisting of Asp-30, His-65, and Ser-369. The amino acid sequence contained the following regions which were assigned on the basis of homology to previously described sequences: a signal peptide (26 residues), a propeptide (117 residues), and an extension up to the C terminus (about 250 residues). Another feature of SapSh is the fact that the space between His-65 and Ser-369 is approximately 150 residues longer than the corresponding spaces in other proteases belonging to the subtilisin family. SapSh was purified to homogeneity from the culture supernatant of E. coli recombinant cells by affinity chromatography with a bacitracin-Sepharose column. The recombinant SapSh (rSapSh) was found to have a molecular weight of about 44,000 and to be highly active in the alkaline region (optimum pH, around 9.0) when azocasein and synthetic peptides were used as substrates. rSapSh was characterized by its high levels of activity at low temperatures; it was five times more active than subtilisin Carlsberg at temperatures ranging from 5 to 15 degreesC. The activation energy for hydrolysis of azocasein by rSapSh was much lower than the activation energy for hydrolysis of azocasein by the subtilisin. However, rSapSh was far less stable than the subtilisin.
Collapse
Affiliation(s)
- L Kulakova
- Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu 611, Japan
| | | | | | | | | |
Collapse
|
48
|
Abstract
Various vitamin B6 enzymes play important roles in mammalian and microbial metabolism of selenium amino acids. Selenocysteine is synthesized from selenohomocysteine by catalysis of cystathionine beta-synthase and cystathionine gamma-lyase, which both require pyridoxal phosphate. Selenocysteine beta-lyase, a new B6-enzyme, exclusively catalyzes beta-elimination of selenocysteine, and occurs in mammalian systems and bacteria. Methionine gamma-lyase, cysteine desulfurase, cysteine sulfinate desulfinase, and D-selenocystine alpha,beta-lyase, which are B6-enzymes, act on cysteine, cysteine sulfinate, D-cystine, and their derivatives, and their selenium counterparts indiscriminately. Their reaction mechanisms are comparatively described.
Collapse
Affiliation(s)
- K Soda
- Department of Biotechnology, Faculty of Engineering, Kansai University, Suita, Osaka-Fu, Japan
| | | | | |
Collapse
|
49
|
Abstract
The pyridoxal form of alanine racemase of Bacillus stearothermophilus was converted to the pyridoxamine form by incubation with its natural substrate, D- or L-alanine, under acidic conditions: the enzyme loses its racemase activity concomitantly. The pyridoxamine form of the enzyme returned to the pyridoxal form by incubation with pyruvate at alkaline pH. Thus, alanine racemase catalyzes transamination as a side function. In fact, the apo-form of the enzyme abstracted tritium from [4'-3H]pyridoxamine in the presence of pyruvate. A mutant enzyme containing alanine substituted for Lys39, whose epsilon-amino group forms a Schiff base with the C4' aldehyde of pyridoxal 5'-phosphate in the wild-type enzyme, was inactive as a catalyst for racemization as well as transamination. However, when methylamine was added to the mutant enzyme, it became active in both reactions. These results suggest that the epsilon-amino group of Lys39 participates in both racemization and transamination when catalyzed by the wild-type enzyme.
Collapse
Affiliation(s)
- Y Kurokawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | | | | | | | | |
Collapse
|
50
|
Liu JQ, Kurihara T, Ichiyama S, Miyagi M, Tsunasawa S, Kawasaki H, Soda K, Esaki N. Reaction mechanism of fluoroacetate dehalogenase from Moraxella sp. B. J Biol Chem 1998; 273:30897-902. [PMID: 9812982 DOI: 10.1074/jbc.273.47.30897] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [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: 11/06/2022] Open
Abstract
Fluoroacetate dehalogenase (EC 3.8.1.3) catalyzes the dehalogenation of fluoroacetate and other haloacetates. The amino acid sequence of fluoroacetate dehalogenase from Moraxella sp. B is similar to that of haloalkane dehalogenase (EC 3.8.1.5) from Xanthobacter autotrophicus GJ10 in the regions around Asp-105 and His-272, which correspond to the active site nucleophile Asp-124 and the base catalyst His-289 of the haloalkane dehalogenase, respectively (Krooshof, G. H., Kwant, E. M., Damborský, J., Koca, J., and Janssen, D. B. (1997) Biochemistry 36, 9571-9580). After multiple turnovers of the fluoroacetate dehalogenase reaction in H218O, the enzyme was digested with trypsin, and the molecular masses of the peptide fragments formed were measured by ion-spray mass spectrometry. Two 18O atoms were shown to be incorporated into the octapeptide, Phe-99-Arg-106. Tandem mass spectrometric analysis of this peptide revealed that Asp-105 was labeled with two 18O atoms. These results indicate that Asp-105 acts as a nucleophile to attack the alpha-carbon of the substrate, leading to the formation of an ester intermediate, which is subsequently hydrolyzed by the nucleophilic attack of a water molecule on the carbonyl carbon atom. A His-272 --> Asn mutant (H272N) showed no activity with either fluoroacetate or chloroacetate. However, ion-spray mass spectrometry revealed that the H272N mutant enzyme was covalently alkylated with the substrate. The reaction of the H272N mutant enzyme with [14C]chloroacetate also showed the incorporation of radioactivity into the enzyme. These results suggest that His-272 probably acts as a base catalyst for the hydrolysis of the covalent ester intermediate.
Collapse
Affiliation(s)
- J Q Liu
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | | | | | |
Collapse
|