Protein purification: protein purification for structural proteomics.
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A recombinant B. megaterium strain was used for the heterologous production of a glucosyltransferase (dextransucrase). To better understand the physiological and metabolic responses of the host cell to cultivation and induction conditions, proteomic analysis was carried out by combined use of two-dimensional gel electrophoresis and mass spectrometry (2-DE/MS) for protein separation and identification. 2-DE method was optimized for the separation of intracellular proteins. Since the genome of B. megaterium is not yet available, peptide sequencing using peptide fragment information obtained from nanoelectrospray ionization quadrupole-time-of-flight tandem mass spectrometry (ESI-QqTOF MS/MS) was applied for protein identification. 167 protein spots were identified as 149 individual proteins, including most enzymes involved in the central carbon metabolic pathways and many enzymes related to amino acid synthesis and protein synthesis. Based on the results a 2-DE reference map and a corresponding protein database were constructed for further proteomic approaches on B. megaterium. For the first time it became possible to perform comparative proteomic analysis on B. megaterium in a batch culture grown on glucose with xylose induction for dextrasucrase production. No significant differences were observed in the expression changes of enzymes of the glycolysis and TCA cycle, indicating that dextransucrase production, which amounted to only 2 % of the entire protein production, did not impose notable metabolic or energetic burdens on the central carbon metabolic pathway of the cells. However, a short-term up-regulation of aspartate aminotransferase, an enzyme closely related to dextransucrase production, in the induced culture demonstrated the feasibility to use 2-DE method for monitoring dextransucrase production. It was also observed that under the cultivation conditions used in this study B. megaterium tended to channel acetyl-CoA into pathways of polyhydroxybutyrate production. No expression increases were found with cytosolic chaperones such as GroEL and DnaK during dextransucrase production and secretion, whereas a strong up-regulation of the oligopeptide-binding protein OppA was observed in correlation with an increased secretion of dextransucrase into the culture medium.
OBJECTIVE: To review the advances in clinically useful molecular biological techniques and their applications in clinical practice as presented at the Ninth Annual William Beaumont Hospital DNA Symposium. DATA SOURCES: The 10 manuscripts submitted were reviewed and their major findings were compared with literature on the same topic. STUDY SELECTION: One manuscript reviewed the development of pharmacogenetics, 3 described analytic approaches to detect aneuploidy or cancer, 1 described transcription factor E2F-1 increase during apoptosis, 2 reported on genetic and pharmacologic factors that influence platelet aggregation, 2 described molecular methods for detecting long QT syndrome or mycobacteria, and 1 reported a modification in collection of buccal DNA. DATA SYNTHESIS: Genomic and proteomic approaches to develop clinically useful assays have been successful. Aneuploidy can be easily detected by comparative genomic hybridization, which does not require cell culture like cytogenetics. Mutations have been characterized for a variety of hereditary cancer syndromes, 2 inherited long QT syndromes, and thromboembolism. PlA1 and PlA2 polymorphisms in platelets are associated with a difference in aggregation inhibition by estrogen, another example of genotypic pharmacogenetics. Protein expression differences may define colorectal cancer stage and explain apoptotic signal transduction. Mycobacterial detection by nucleic acid amplification and simplified buccal DNA collection demonstrate cost-effective strategies. CONCLUSION: The working draft of the Human Genome Project is completed and the number of clinically useful molecular pathologic techniques and assays will expand as additional disease-associated mutations are defined. Expanded use of database software for genomic and proteomic screening should increase the efficiency of clinical useful assay development.
High-throughput structural proteomics is expected to generate considerable amounts of data on the progress of structure determination for many proteins. For each protein this includes information about cloning, expression, purification, biophysical characterization and structure determination via NMR spectroscopy or X-ray crystallography. It will be essential to develop specifications and ontologies for standardizing this information to make it amenable to retrospective analysis. To this end we created the SPINE database and analysis system for the Northeast Structural Genomics Consortium. SPINE, which is available at bioinfo.mbb.yale.edu/nesg or nesg.org, is specifically designed to enable distributed scientific collaboration via the Internet. It was designed not just as an information repository but as an active vehicle to standardize proteomics data in a form that would enable systematic data mining. The system features an intuitive user interface for interactive retrieval and modification of expression construct data, query forms designed to track global project progress and external links to many other resources. Currently the database contains experimental data on 985 constructs, of which 740 are drawn from Methanobacterium thermoautotrophicum, 123 from Saccharomyces cerevisiae, 93 from Caenorhabditis elegans and the remainder from other organisms. We developed a comprehensive set of data mining features for each protein, including several related to experimental progress (e.g. expression level, solubility and crystallization) and 42 based on the underlying protein sequence (e.g. amino acid composition, secondary structure and occurrence of low complexity regions). We demonstrate in detail the application of a particular machine learning approach, decision trees, to the tasks of predicting a protein's solubility and propensity to crystallize based on sequence features. We are able to extract a number of key rules from our trees, in particular that soluble proteins tend to have significantly more acidic residues and fewer hydrophobic stretches than insoluble ones. One of the characteristics of proteomics data sets, currently and in the foreseeable future, is their intermediate size ( approximately 500-5000 data points). This creates a number of issues in relation to error estimation. Initially we estimate the overall error in our trees based on standard cross-validation. However, this leaves out a significant fraction of the data in model construction and does not give error estimates on individual rules. Therefore, we present alternative methods to estimate the error in particular rules.
The Arabidopsis Nucleolar Protein Database (http://bioinf.scri.sari.ac.uk/cgi-bin/atnopdb/home) provides information on 217 proteins identified in a proteomic analysis of nucleoli isolated from Arabidopsis cell culture. The database is organized on the basis of the Arabidopsis gene identifier number. The information provided includes protein description, protein class, whether or not the plant protein has a homologue in the most recent human nucleolar proteome and the results of reciprocal BLAST analysis of the human proteome. In addition, for one-third of the 217 Arabidopsis nucleolar proteins, localization images are available from analysis of full-length cDNA-green fluorescent protein (GFP) fusions and the strength of signal in different parts of the cell-nucleolus, nucleolus-associated structures, nucleoplasm, nuclear bodies and extra-nuclear-is provided. For each protein, the most likely human and yeast orthologues, where identifiable through BLASTX analysis, are given with links to relevant information sources.
A report on the Fourth Annual HUPO World Congress (HUPO2005) 'From Defining the Proteome to Understanding Function', Munich, Germany, 28 August-1 September 2005.
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Although genome databases have become the key for proteomic analyses, de novo sequencing remains essential for the study of organisms whose genomes have not been completed. In addition, post-translational modifications present a challenge in database searching. Recognition of the b or y-ion series in a peptide MS/MS spectrum as well as identification of the b1 - and yn-1 -ions can facilitate de novo analyses. Therefore, it is valuable to identify either amino-acid terminus. In previous work, we have demonstrated that peptides modified at the epsilon-amino group of lysine as a t-butyl peroxycarbamate derivative undergo free radical promoted peptide backbone fragmentation under low-energy collision-induced dissociation (CID) conditions. Here we explore the chemistry of the N-terminal amino group modified as a t-butyl peroxycarbamate. The conversion of N-terminal amines to peroxycarbamates of simple amino acids and peptides was studied with aryl t-butyl peroxycarbonates. ESI-MS/MS analysis of the peroxycarbamate adducts gave evidence of a product ion corresponding to the neutral loss of the N-terminal side chain (R), thus identifying this residue. Further fragmentation (MS3) of product ions formed by N-terminal residue side-chain loss (-R) exhibited an m/z shift of the b-ions equal to the neutral loss of R, therefore labeling the b-ion series. The study was extended to the analysis of a protein tryptic digest where the SALSA algorithm was used to identify spectra containing these neutral losses. The method for N-terminus identification presented here has the potential for improvement of de novo analyses as well as in constraining peptide mass mapping database searches.
Proteomics has emerged as a major discipline that led to a re-examination of the need for consensus and a nationally sanctioned set of proteomics technology standards. Such standards for databases and data reporting may be applied to two-dimensional polyacrylamide gel electrophoresis (2D PAGE) technology as a pilot project for assessing global and national needs in proteomics, and the role of the National Institute of Standards and Technology (NIST) and other similar standards and measurement organizations. The experience of harmonizing the heterogeneous data included in the Protein Data Bank (PDB) provides a paradigm for technology in an area where significant heterogeneity in technical detail and data storage has evolved. Here we propose an approach toward standardizing mitochondrial 2D PAGE data in support of a globally relevant proteomics consensus.
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The emergence of proteomics, the large-scale analysis of proteins, has been inspired by the realization that the final product of a gene is inherently more complex and closer to function than the gene itself. Shortfalls in the ability of bioinformatics to predict both the existence and function of genes have also illustrated the need for protein analysis. Moreover, only through the study of proteins can posttranslational modifications be determined, which can profoundly affect protein function. Proteomics has been enabled by the accumulation of both DNA and protein sequence databases, improvements in mass spectrometry, and the development of computer algorithms for database searching. In this review, we describe why proteomics is important, how it is conducted, and how it can be applied to complement other existing technologies. We conclude that currently, the most practical application of proteomics is the analysis of target proteins as opposed to entire proteomes. This type of proteomics, referred to as functional proteomics, is always driven by a specific biological question. In this way, protein identification and characterization has a meaningful outcome. We discuss some of the advantages of a functional proteomics approach and provide examples of how different methodologies can be utilized to address a wide variety of biological problems.
The proteome is expected to be thoroughly researched in Post Genome Projects following the completion of the Human Genome Sequencing Project. Many research projects to investigate disease-related proteins are being undertaken worldwide. Analysis of the proteome, which has an intimate involvement in biogenics, should provide a breakthrough in vital activity and provide substantial clues for new treatments, diagnoses and new target of drugs. In the 2003 fiscal year, The Ministry of Health, Labour and Welfare (MHLW) started the Health, Labour and Welfare Scientific Research Founding Program "Disease Related Proteomics". At the time, the Japan Health Sciences Foundation was delegated the project from MHLW, along with the Japan Pharmaceutical Manufactures Association, and established a consortium with 22 pharmaceutical companies for this project, collaborating with the National Institute of Health Science to start the Project on Disease Related Proteomics and a Proteome Factory for Drug Innovation. In this report, the project overview and its facilities will be introduced.
Global measurement of proteins and their many attributes in tissues and biofluids defines the field of proteomics. Toxicoproteomics, as part of the larger field of toxicogenomics. seeks to identify critical proteins and pathways in biological systems that are affected by and respond to adverse chemical and environmental exposures using global protein expression technologies. Toxicoproteomics integrates 3 disciplinary areas: traditional toxicology and pathology, differential protein and gene expression analysis, and systems biology. Key topics to be reviewed are the evolution of proteomics, proteomic technology platforms and their capabilities with exemplary studies from biology and medicine, a review of over 50 recent studies applying proteomic analysis to toxicological research, and the recent development of databases designed to integrate -Omics technologies with toxicology and pathology. Proteomics is examined for its potential in discovery of new biomarkers and toxicity signatures, in mapping serum,plasma. and other biofluid proteomes, and in parallel proteomic and transcriptomic studies. The new field of toxicoproteomics is uniquely positioned toward an expanded understanding of protein expression during toxicity and environmental disease for the advancement of public health.
ToxoDB (http://ToxoDB.org) provides a genome resource for the protozoan parasite Toxoplasma gondii. Several sequencing projects devoted to T. gondii have been completed or are in progress: an EST project (http://genome.wustl.edu/est/index.php?toxoplasma=1), a BAC clone end-sequencing project (http://www.sanger.ac.uk/Projects/T_gondii/) and an 8X random shotgun genomic sequencing project (http://www.tigr.org/tdb/e2k1/tga1/). ToxoDB was designed to provide a central point of access for all available T. gondii data, and a variety of data mining tools useful for the analysis of unfinished, un-annotated draft sequence during the early phases of the genome project. In later stages, as more and different types of data become available (microarray, proteomic, SNP, QTL, etc.) the database will provide an integrated data analysis platform facilitating user-defined queries across the different data types.
The PathoSystems Resource Integration Center (PATRIC) is one of eight Bioinformatics Resource Centers (BRCs) funded by the National Institute of Allergy and Infection Diseases (NIAID) to create a data and analysis resource for selected NIAID priority pathogens, specifically proteobacteria of the genera Brucella, Rickettsia and Coxiella, and corona-, calici- and lyssaviruses and viruses associated with hepatitis A and E. The goal of the project is to provide a comprehensive bioinformatics resource for these pathogens, including consistently annotated genome, proteome and metabolic pathway data to facilitate research into counter-measures, including drugs, vaccines and diagnostics. The project's curation strategy has three prongs: 'breadth first' beginning with whole-genome and proteome curation using standardized protocols, a 'targeted' approach addressing the specific needs of researchers and an integrative strategy to leverage high-throughput experimental data (e.g. microarrays, proteomics) and literature. The PATRIC infrastructure consists of a relational database, analytical pipelines and a website which supports browsing, querying, data visualization and the ability to download raw and curated data in standard formats. At present, the site warehouses complete sequences for 17 bacterial and 332 viral genomes. The PATRIC website (https://patric.vbi.vt.edu) will continually grow with the addition of data, analysis and functionality over the course of the project.
OBJECTIVES: To review the advances in clinically useful molecular biological techniques and to identify their applications in clinical practice, as presented at the Tenth Annual William Beaumont Hospital DNA Symposium. DATA SOURCES: The 11 manuscripts submitted were reviewed and their major findings were compared with literature on the same topic. STUDY SELECTION: Manuscripts address creative thinking techniques applied to DNA discovery, extraction of DNA from clotted blood, the relationship of mitochondrial dysfunction in neurodegenerative disorders, and molecular methods to identify human lymphocyte antigen class I and class II loci. Two other manuscripts review current issues in molecular microbiology, including detection of hepatitis C virus and biological warfare. The last 5 manuscripts describe current issues in molecular cardiovascular disease, including assessing thrombotic risk, genomic analysis, gene therapy, and a device for aiding in cardiac angiogenesis. DATA SYNTHESIS: Novel problem-solving techniques have been used in the past and will be required in the future in DNA discovery. The extraction of DNA from clotted blood demonstrates a potential cost-effective strategy. Cybrids created from mitochondrial DNA-depleted cells and mitochondrial DNA from a platelet donor have been useful in defining the role mitochondria play in neurodegeneration. Mitochondrial depletion has been reported as a genetically inherited disorder or after human immunodeficiency virus therapy. Hepatitis C viral detection by qualitative, quantitative, or genotyping techniques is useful clinically. Preparedness for potential biological warfare is a responsibility of all clinical laboratorians. Thrombotic risk in cardiovascular disorders may be assessed by coagulation screening assays and further defined by mutation analysis for specific genes for prothrombin and factor V Leiden. Gene therapy for reducing arteriosclerotic risk has been hindered primarily by complications introduced by the vectors used to introduce the therapeutic genes. Neovascularization in cardiac muscle with occluded vessels represents a promising method for recovery of viable tissue following ischemia. CONCLUSIONS: The sequence of the human genome was reported by 2 groups in February 2001. The postgenomic era will emphasize the use of microarrays and database software for genomic and proteomic screening in the search for useful clinical assays. The number of molecular pathologic techniques and assays will expand as additional disease-associated mutations are defined. Gene therapy and tissue engineering will represent successful therapeutic adjuncts.
CONTEXT: The field of molecular pathology is expanding in complexity. To achieve competency, vigilance is required. OBJECTIVE: To review the advances in clinically useful molecular biologic techniques and to identify their applications in clinical practice, as presented at the 13th Annual William Beaumont Hospital DNA Symposium. DATA SOURCES: The 4 manuscripts submitted were reviewed and their major findings were compared with the literature on the same or related topics. STUDY SELECTION: Manuscripts address the use of molecular or immunophenotyping by flow cytometry to evaluate the origin or presence of sepsis, respectively; the use of imatinib mesylate to treat chronic myeloid leukemia and the nature of resistance to imatinib; and the use of 9 and 10 fluorochromes during clinical flow cytometric studies. DATA SYNTHESIS: The epidemiologic evaluation of a septic outbreak may be monitored using molecular techniques that track the relatedness of isolates. A potential biomarker for the presence of early sepsis is CD64. Intracellular signal transduction pathways are altered in malignancy. Imatinib mesylate inhibits the BCR-ABL kinase created by translocation of the long arms of chromosomes 9 and 22 in chronic myeloid leukemia. Resistance to imatinib may be secondary to mutation in the BCR-ABL kinase domain or residual leukemic stem cells that imatinib does not kill. The use of 9 or 10 fluorochromes simultaneously during flow cytometry has many clinical advantages; however, software for data analysis is needed. CONCLUSION: The current postgenomic era will continue to emphasize the use of microarrays and database software for genomic, transcriptomic, proteomic, nutrigenomic, and pharmacogenomics screening to search for a useful clinical assay. The number of molecular pathologic techniques will expand as additional disease-associated mutations are defined.