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Ren JY, Xu M, Niu XD, Ma SX, Jiao YJ, Wang D, Yu M, Cai H. Systemic inflammatory response index is a predictor of prognosis in gastric cancer patients: Retrospective cohort and meta-analysis. World J Gastrointest Surg 2024; 16:382-395. [PMID: 38463377 PMCID: PMC10921201 DOI: 10.4240/wjgs.v16.i2.382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/25/2023] [Accepted: 02/01/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND The systemic inflammatory response index (SIRI) has been demonstrated to make a significant difference in assessing the prognosis of patients with different solid neoplasms. However, research is needed to ascertain the accuracy and reliability of applying the SIRI to patients who undergo robotic radical gastric cancer surgery. AIM To validate the applicability of the SIRI in assessing the survival of gastric cancer patients and evaluate the clinical contribution of preoperative SIRI levels to predicting long-term tumor outcomes in patients, who received robotic radical gastric cancer surgery. METHODS Initially, an exhaustive retrieval was performed in the PubMed, the Cochrane Library, EMBASE, Web of Science, and Scopus databases to identify relevant studies. Subsequently, a meta-analysis was executed on 6 cohort studies identifying the value of the SIRI in assessing the survival of gastric cancer patients. Additionally, the clinical data of 161 patients undergoing robotic radical gastric cancer surgery were retrospectively analyzed to evaluate their clinicopathological characteristics and relevant laboratory indicators. The association between preoperative SIRI levels and 5-year overall survival (OS) and disease-free survival (DFS) was assessed. RESULTS The findings demonstrated an extensive connection between SIRI values and the outcome of patients with gastric cancer. Preoperative SIRI levels were identified as an independent hazard feature for both OS and DFS among those who received robotic surgery for gastric cancer. SIRI levels in gastric cancer patients were observed to be associated with the presence of comorbidities, T-stage, carcinoembryonic antigen levels, the development of early serious postoperative complications, and the rate of lymph node metastasis. CONCLUSION SIRI values are correlated with adverse in the gastric cancer population and have the potential to be utilized in predicting long-term oncological survival in patients who undergo robotic radical gastric cancer surgery.
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Affiliation(s)
- Jing-Yao Ren
- School of Clinical Medicine, Ningxia Medical University, Yinchuan 750000, Ningxia Hui autonomous region, China
| | - Meng Xu
- Gansu Provincial Hospital, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Xiang-Dong Niu
- General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Shi-Xun Ma
- General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Ya-Jun Jiao
- General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Da Wang
- Medical College of Jiangsu University, Jiangsu University, Zhenjiang 212013, Jiangsu Province, China
| | - Miao Yu
- Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Hui Cai
- General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
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2
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Han XY, Li X, Zhao RY, Ma HZ, Yu M, Niu XD, Jin HJ, Wang YF, Liu DM, Cai H. Comprehensive analysis of prognostic value and immunotherapy prospect of brain cytoplasmic RNA1 in hepatocellular carcinoma. World J Gastrointest Oncol 2023; 15:644-664. [PMID: 37123057 PMCID: PMC10134208 DOI: 10.4251/wjgo.v15.i4.644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/18/2023] [Accepted: 03/16/2023] [Indexed: 04/12/2023] Open
Abstract
BACKGROUND The expression of brain cytoplasmic RNA1 (BCYRN1) is linked to the clinicopathology and prognosis of several types of cancers, among which hepatocellular carcinoma (HCC) is one of the most frequent types of cancer worldwide.
AIM To explore the prognostic value and immunotherapeutic potential of BCYRN1 in HCC by bioinformatics and meta-analysis.
METHODS Information was obtained from the Cancer Genome Atlas database. First, the correlation between BCYRN1 expression and prognosis and clinicopathologic characteristics of HCC patients was explored. Univariate and multivariate regression analyses were employed to examine the relationship between BCYRN1 and HCC prognosis. Secondly, potential functions and pathways were explored by means of enrichment analysis of differentially-expressed genes. The relationships between BCYRN1 expression and tumor microenvironment, immune cell infiltration, immune checkpoint, drug sensitivity and immunotherapy effect were also investigated. Finally, three major databases were searched and used to conduct a meta-analysis on the relationship between BCYRN1 expression and patient prognosis.
RESULTS BCYRN1 expression was significantly higher in HCC compared to normal tissues and was linked to a poor prognosis and clinicopathological characteristics. Enrichment analysis showed that BCYRN1 regulates the extracellular matrix and transmission of signaling molecules, participates in the metabolism of nutrients, such as proteins, and participates in tumor-related pathways. BCYRN1 expression was linked to the tumor microenvironment, immune cell infiltration, drug sensitivity and the efficacy of immunotherapy. Furthermore, the meta-analysis in this study showed that BCYRN1 overexpression was related to a worse outcome in HCC patients.
CONCLUSION Overexpression of BCYRN1 relates to poor prognosis and may be a potential prognostic factor and immunotherapeutic target in HCC.
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Affiliation(s)
- Xiao-Yong Han
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Graduate School, Ningxia Medical University, Yinchuan 750004, Ningxia Hui Autonomous Region, China
- Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Xiong Li
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Graduate School, Ningxia Medical University, Yinchuan 750004, Ningxia Hui Autonomous Region, China
| | - Rang-Yin Zhao
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- The First Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou 730000, Gansu Province, China
| | - Hai-Zhong Ma
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- The First Clinical College of Medicine, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Miao Yu
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Xiang-Dong Niu
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Hao-Jie Jin
- The First Clinical College of Medicine, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Yong-Feng Wang
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- The First Clinical College of Medicine, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - De-Ming Liu
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
| | - Hui Cai
- Gansu General Surgery Clinical Medical Center, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
- Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou 730000, Gansu Province, China
- NHC Key Laboratory of Diagnosis and Therapy of Gastrointestinal Tumor, Gansu Provincial Hospital, Lanzhou 730000, Gansu Province, China
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3
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Shu C, Niu XD, Chew YT. Taylor-series expansion and least-squares-based lattice Boltzmann method: Two-dimensional formulation and its applications. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 65:036708. [PMID: 11909308 DOI: 10.1103/physreve.65.036708] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2001] [Indexed: 05/23/2023]
Abstract
An explicit lattice Boltzmann method (LBM) is developed in this paper to simulate flows in an arbitrary geometry. The method is based on the standard LBM, Taylor-series expansion, and the least-squares approach. The final formulation is an algebraic form and essentially has no limitation on the mesh structure and lattice model. Theoretical analysis for the one-dimensional (1D) case showed that the version of the LBM could recover the Navier-Stokes equations with second order accuracy. A generalized hydrodynamic analysis is conducted to study the wave-number dependence of shear viscosity for the method. Numerical simulations of the 2D lid-driven flow in a square cavity and a polar cavity flow as well as the "no flow" simulation in a square cavity have been carried out. Favorable results were obtained and compared well with available data in the literature, indicating that the present method has good prospects in practical applications.
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Affiliation(s)
- C Shu
- Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 117576
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4
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Shu C, Chew YT, Niu XD. Least-squares-based lattice Boltzmann method: a meshless approach for simulation of flows with complex geometry. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:045701. [PMID: 11690083 DOI: 10.1103/physreve.64.045701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2001] [Indexed: 05/23/2023]
Abstract
A version of lattice Boltzmann method (LBM) is presented in this work, which is derived from the standard LBM by using Taylor series expansion and optimized by the least squares method. The method is basically meshless, and can be applied to any complex geometry and nonuniform grids. It can also be applied to different lattice models. The proposed method explicitly updates the distribution functions at mesh points by an algebraic formulation, in which the relevant coefficients are precomputed from the coordinates of mesh points. We have successfully applied this method to simulate many two-dimensional incompressible viscous flows. The numerical results are very accurate, and the computational time needed is much less as compared with other existing methods. In this paper, we mainly show the method.
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Affiliation(s)
- C Shu
- Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
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5
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Cook DN, Prosser DM, Forster R, Zhang J, Kuklin NA, Abbondanzo SJ, Niu XD, Chen SC, Manfra DJ, Wiekowski MT, Sullivan LM, Smith SR, Greenberg HB, Narula SK, Lipp M, Lira SA. CCR6 mediates dendritic cell localization, lymphocyte homeostasis, and immune responses in mucosal tissue. Immunity 2000; 12:495-503. [PMID: 10843382 DOI: 10.1016/s1074-7613(00)80201-0] [Citation(s) in RCA: 377] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemokine-directed migration of leukocyte subsets may contribute to the qualitative differences between systemic and mucosal immunity. Here, we demonstrate that in mice lacking the chemokine receptor CCR6, dendritic cells expressing CD11c and CD11b are absent from the subepithelial dome of Peyer's patches. These mice also have an impaired humoral immune response to orally administered antigen and to the enteropathic virus rotavirus. In addition, CCR6(-/-) mice have a 2-fold to 15-fold increase in cells of select T lymphocyte populations within the mucosa, including CD4+ and CD8+ alphabeta-TCR T cells. By contrast, systemic immune responses to subcutaneous antigens in CCR6(-/-) mice are normal. These findings demonstrate that CCR6 is a mucosa-specific regulator of humoral immunity and lymphocyte homeostasis in the intestinal mucosa.
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Affiliation(s)
- D N Cook
- Department of Immunology, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
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6
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Fischmann TO, Hruza A, Niu XD, Fossetta JD, Lunn CA, Dolphin E, Prongay AJ, Reichert P, Lundell DJ, Narula SK, Weber PC. Structural characterization of nitric oxide synthase isoforms reveals striking active-site conservation. Nat Struct Biol 1999; 6:233-42. [PMID: 10074942 DOI: 10.1038/6675] [Citation(s) in RCA: 329] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Crystal structures of human endothelial nitric oxide synthase (eNOS) and human inducible NOS (iNOS) catalytic domains were solved in complex with the arginine substrate and an inhibitor S-ethylisothiourea (SEITU), respectively. The small molecules bind in a narrow cleft within the larger active-site cavity containing heme and tetrahydrobiopterin. Both are hydrogen-bonded to a conserved glutamate (eNOS E361, iNOS E377). The active-site residues of iNOS and eNOS are nearly identical. Nevertheless, structural comparisons provide a basis for design of isozyme-selective inhibitors. The high-resolution, refined structures of eNOS (2.4 A resolution) and iNOS (2.25 A resolution) reveal an unexpected structural zinc situated at the intermolecular interface and coordinated by four cysteines, two from each monomer.
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Affiliation(s)
- T O Fischmann
- Structural Chemistry Department, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
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7
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Abstract
We have expressed active full-length human inducible nitric oxide synthase (iNOS) in E. coli. Expression required co-expression with calmodulin, a particularly tight-binding cofactor. The extracts also required tetrahydrobiopterin to display activity. Specific activity of the purified recombinant iNOS was similar to iNOS purified from murine macrophages. This result indicates that no special processing events unique to eucaryotic cells are necessary for iNOS activity.
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Affiliation(s)
- J D Fossetta
- Department of Immunology, Schering-Plough Research Institute, Kenilworth, NJ 07003, USA
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8
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Maeng CY, Yazdi MA, Niu XD, Lee HY, Reed LJ. Expression, purification, and characterization of the dihydrolipoamide dehydrogenase-binding protein of the pyruvate dehydrogenase complex from Saccharomyces cerevisiae. Biochemistry 1994; 33:13801-7. [PMID: 7947791 DOI: 10.1021/bi00250a034] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Genes encoding dihydrolipoamide dehydrogenase (E3) and the E3-binding protein (E3BP, protein X), components of the Saccharomyces cerevisiae pyruvate dehydrogenase (PDH) complex, were coexpressed in Escherichia coli to produce an E3BP-E3 complex, thereby minimizing proteolysis of E3BP and facilitating its purification. The 2 genes were linked into a single transcriptional unit separated by a 31-nucleotide segment containing a ribosome-binding sequence. The E3BP-E3 complex was highly purified and then separated into E3 and E3BP by chromatography on hydroxylapatite in the presence of 5 M urea. The E3BP-E3 complex combined rapidly with a pyruvate dehydrogenase (E1)-dihydrolipoamide acetyltransferase (E2) subcomplex (E1-E2 subcomplex) to reconstitute a functional PDH complex, with pyruvate oxidation activity similar to that of PDH complex from bakers' yeast. The stoichiometry of binding of E3BP and E3BP-E3 complex to the 60-subunit pentagonal dodecahedron-like E2 was determined with a truncated form of E2 (tE2, residues 206-454) lacking the lipoyl domain and the E1-binding domain, and with E1-E2 subcomplex, which contains intact E2. Mixtures containing tE2 or E1-E2 subcomplex and excess E3BP or E3BP-E3 complex were subjected to ultracentrifugation to separate the large complexes from unbound E3BP or E3BP-E3, and the complexes were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After staining with Coomassie brilliant blue and destaining, the gels were analyzed with a video area densitometer. The results showed that the E1-E2 subcomplex binds about 12 E3BP monomers attached to 12 E3 homodimers. Similar results were obtained by analysis of highly purified PDH complex from bakers' yeast.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C Y Maeng
- Biochemical Institute, University of Texas at Austin 78712
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9
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Lawson JE, Niu XD, Browning KS, Trong HL, Yan J, Reed LJ. Molecular cloning and expression of the catalytic subunit of bovine pyruvate dehydrogenase phosphatase and sequence similarity with protein phosphatase 2C. Biochemistry 1993; 32:8987-93. [PMID: 8396421 DOI: 10.1021/bi00086a002] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
After many unsuccessful attempts to detect cDNA encoding the catalytic subunit of bovine pyruvate dehydrogenase phosphatase (PDPc) in bovine cDNA libraries, an approach based on the polymerase chain reaction (PCR) was undertaken. Overlapping DNA fragments were generated by PCR from bovine genomic DNA and from cDNA synthesized from total RNA with synthetic oligonucleotide primers on the basis of experimentally determined amino acid sequences. The DNA fragments were subcloned and sequenced. The complete cDNA is 1900 base pairs in length and contains an open reading frame of 1614 nucleotides encoding a putative presequence of 71 amino acid residues and a mature protein of 467 residues with a calculated M(r) of 52,625. Hybridization analysis showed a single mRNA transcript of about 2.0 kilobases. Comparison of the deduced amino acid sequences of the mitochondrial PDPc and the rat cytosolic protein phosphatase 2C indicates that these protein serine/threonine phosphatases evolved from a common ancestor. The mature form of PDPc was coexpressed in Escherichia coli with the chaperonin proteins groEL and groES. The recombinant protein (rPDPc) was purified to near homogeneity. Its activity toward the bovine 32P-labeled pyruvate dehydrogenase complex was Mg(2+)-dependent and Ca(2+)-stimulated and comparable to that of native bovine PDP. An active, truncated form of rPDPc, with M(r) approximately 45,000, was produced in variable amounts during growth of cells and/or during the purification procedure.
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Affiliation(s)
- J E Lawson
- Biochemical Institute, University of Texas at Austin 78712
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10
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Stoops JK, Baker TS, Schroeter JP, Kolodziej SJ, Niu XD, Reed LJ. Three-dimensional structure of the truncated core of the Saccharomyces cerevisiae pyruvate dehydrogenase complex determined from negative stain and cryoelectron microscopy images. J Biol Chem 1992; 267:24769-75. [PMID: 1280269 PMCID: PMC4167662] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dihydrolipoamide acyltransferase (E2), a catalytic and structural component of the three functional classes of multienzyme complexes that catalyze the oxidative decarboxylation of alpha-keto acids, forms the central core to which the other components are attached. We have imaged by negative stain and cryoelectron microscopy the truncated dihydrolipoamide acetyltransferase core (60 subunits; M(r) = 2.7 x 10(6)) of the Saccharomyces cerevisiae pyruvate dehydrogenase complex. Using icosahedral particle reconstruction techniques, we determined its structure to 25 A resolution. Although the model derived from the negative stain reconstruction was approximately 20% smaller than the model derived from the frozen-hydrated data, when corrected for the effects of the electron microscope contrast transfer functions, the reconstructions showed excellent correspondence. The pentagonal dodecahedron-shaped macromolecule has a maximum diameter, as measured along the 3-fold axis, of approximately 226 A (frozen-hydrated value), and 12 large openings (approximately 63 A in diameter) on the 5-fold axes that lead into a large solvent-accessible cavity (approximately 76-140 A diameter). The 20 vertices consist of cone-shaped trimers, each with a flattened base on the outside of the structure and an apex directed toward the center. The trimers are interconnected by 20 A thick "bridges" on the 2-fold axes. These studies also show that the highest resolution features apparent in the frozen-hydrated reconstruction are revealed in a filtered reconstruction of the stained molecule.
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Affiliation(s)
- J K Stoops
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston 77030
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Reed LJ, Lawson JE, Niu XD, Yazdi MA, Fussey SP. Biochemical and molecular genetic aspects of eukaryotic pyruvate dehydrogenase multienzyme complexes. J Nutr Sci Vitaminol (Tokyo) 1992; Spec No:46-51. [PMID: 1297788 DOI: 10.3177/jnsv.38.special_46] [Citation(s) in RCA: 4] [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: 12/26/2022]
Abstract
The alpha-keto acid dehydrogenase multienzyme complexes play central roles in metabolism, are major sites of regulation, and are clinically important. Genes and cDNAs encoding the components of these complexes have been cloned and sequenced. Protein engineering and molecular cloning experiments are providing new insight into organization, structure-function relationships, and the molecular basis of genetic defects in these multienzyme complexes.
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Affiliation(s)
- L J Reed
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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12
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Abstract
The LAT1 gene encoding the dihydrolipoamide acetyltransferase component (E2) of the pyruvate dehydrogenase (PDH) complex from Saccharomyces cerevisiae was disrupted, and the lat1 null mutant was used to analyze the structure and function of the domains of E2. Disruption of LAT1 did not affect the viability of the cells. Apparently, flux through the PDH complex is not required for growth of S. cerevisiae under the conditions tested. The wild-type and mutant PDH complexes were purified to near-homogeneity and were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and enzyme assays. Mutant cells transformed with LAT1 on a unit-copy plasmid produced a PDH complex very similar to that of the wild-type PDH complex. Deletion of most of the putative lipoyl domain (residues 8-84) resulted in loss of about 85% of the overall activity, but did not affect the acetyltransferase activity of E2 or the binding of pyruvate dehydrogenase (E1), dihydrolipoamide dehydrogenase (E3), and protein X to the truncated E2. Similar results were obtained by deleting the lipoyl domain plus the first hinge region (residues 8-145) and by replacing lysine-47, the putative site of covalent attachment of the lipoyl moiety, by arginine. Although the lipoyl domain of E2 and/or its covalently bound lipoyl moiety were removed, the mutant complexes retained 12-15% of the overall activity of the wild-type PDH complex. Replacement of both lysine-47 in E2 and the equivalent lysine-43 in protein X by arginine resulted in complete loss of overall activity of the mutant PDH complex.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J E Lawson
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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13
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Niu XD, Stoops JK, Reed LJ. Overexpression and mutagenesis of the catalytic domain of dihydrolipoamide acetyltransferase from Saccharomyces cerevisiae. Biochemistry 1990; 29:8614-9. [PMID: 2271545 DOI: 10.1021/bi00489a017] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The inner core domain (residues approximately 221-454) of the dihydrolipoamide acetyltransferase component (E2P) of the pyruvate dehydrogenase complex from Saccharomyces cerevisiae has been overexpressed in Escherichia coli strain JM105 via the expression vector pKK233-2. The truncated E2p was purified to apparent homogeneity. It exhibited catalytic activity (acetyl transfer from [1-14C]acetyl-CoA to dihydrolipoamide) very similar to that of wild-type E2p. The appearance of the truncated and wild-type E2p was also very similar, as observed by negative-stain electron microscopy, namely, a pentagonal dodecahedron. These findings demonstrate that the active site of E2p from S. cerevisiae resides in the inner core domain, i.e., catalytic domain, and that this domain alone can undergo self-assembly. The purified truncated E2p showed a tendency to aggregate. Aggregation was prevented by genetically engineered attachment of the interdomain linker segment (residues approximately 181-220) to the catalytic domain. All dihydrolipoamide acyltransferases contain the sequence His-Xaa-Xaa-Xaa-Asp-Gly near their carboxyl termini. By analogy with chloramphenicol acetyltransferase, the highly conserved His and Asp residues were postulated to be involved in the catalytic mechanism [Guest, J. R. (1987) FEMS Microbiol. Lett. 44, 417-422]. Substitution of the sole His residue in the S. cerevisiae truncated E2p, His-427, by Asn or Ala by site-directed mutagenesis did not have a significant effect on the kcat or Km values of the truncated E2p. However, the Asp-431----Asn, Ala, or Glu substitutions resulted in a 16-, 24-, and 3.7-fold reduction, respectively, in kcat, with little change in Km values.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- X D Niu
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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14
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Reed LJ, Browning KS, Niu XD, Behal RH, Uhlinger DJ. Biochemical and molecular genetic aspects of pyruvate dehydrogenase complex from Saccharomyces cerevisiae. Ann N Y Acad Sci 1989; 573:155-67. [PMID: 2699395 DOI: 10.1111/j.1749-6632.1989.tb14993.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- L J Reed
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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15
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Niu XD, Browning KS, Behal RH, Reed LJ. Cloning and nucleotide sequence of the gene for dihydrolipoamide acetyltransferase from Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 1988; 85:7546-50. [PMID: 3050999 PMCID: PMC282228 DOI: 10.1073/pnas.85.20.7546] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A 537-base cDNA encoding a portion of Saccharomyces cerevisiae dihydrolipoamide acetyltransferase (acetyl-CoA:dihydrolipoamide S-acetyltransferase, EC 2.3.1.12) was isolated from a lambda gt11 yeast cDNA library by immunoscreening. This cDNA was subcloned and used as a probe to screen a lambda gt11 yeast genomic DNA library. Two overlapping clones were used to determine the complete sequence of the acetyltransferase gene. The composite sequence has an open reading frame of 1446 nucleotides encoding a presequence of 28 amino acids and a mature protein of 454 amino acids (Mr = 48,546). The deduced amino acid sequence contains the experimentally determined amino acid sequences of the amino terminus and two internal peptide fragments of the acetyltransferase. Hybridization analysis of yeast genomic DNA showed that the gene has a single copy. A 915-base segment of the acetyltransferase gene hybridized to a yeast mRNA of approximately equal to 1.6 kilobases. Analysis of the deduced amino acid sequence of the dihydrolipoamide acetyltransferase revealed a multidomain structure similar to those reported for the corresponding acetyltransferases from Escherichia coli and rat liver, and extensive sequence similarity among the three enzymes. However, the yeast enzyme contains only one lipoyl domain, in contrast to three lipoyl domains reported for the E. coli enzyme and apparently two for the rat liver enzyme.
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Affiliation(s)
- X D Niu
- Clayton Foundation Biochemical Institute, University of Texas, Austin 78712
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