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Dennig A, Shivange AV, Marienhagen J, Schwaneberg U. OmniChange: the sequence independent method for simultaneous site-saturation of five codons. PLoS One 2011; 6:e26222. [PMID: 22039444 PMCID: PMC3198389 DOI: 10.1371/journal.pone.0026222] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 09/22/2011] [Indexed: 12/20/2022] Open
Abstract
Focused mutant library generation methods have been developed to improve mainly "localizable" enzyme properties such as activity and selectivity. Current multi-site saturation methods are restricted by the gene sequence, require subsequent PCR steps and/or additional enzymatic modifications. Here we report, a multiple site saturation mutagenesis method, OmniChange, which simultaneously and efficiently saturates five independent codons. As proof of principle, five chemically cleaved DNA fragments, each carrying one NNK-degenerated codon, were generated and assembled to full gene length in a one-pot-reaction without additional PCR-amplification or use of restriction enzymes or ligases. Sequencing revealed the presence of up to 27 different codons at individual positions, corresponding to 84.4% of the theoretical diversity offered by NNK-degeneration. OmniChange is absolutely sequence independent, does not require a minimal distance between mutated codons and can be accomplished within a day.
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Affiliation(s)
- Alexander Dennig
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Aachen, Germany
| | - Amol V. Shivange
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Aachen, Germany
| | - Jan Marienhagen
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Aachen, Germany
| | - Ulrich Schwaneberg
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Aachen, Germany
- * E-mail:
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102
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Seufferheld MJ, Kim KM, Whitfield J, Valerio A, Caetano-Anollés G. Evolution of vacuolar proton pyrophosphatase domains and volutin granules: clues into the early evolutionary origin of the acidocalcisome. Biol Direct 2011; 6:50. [PMID: 21974828 PMCID: PMC3198990 DOI: 10.1186/1745-6150-6-50] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/05/2011] [Indexed: 01/08/2023] Open
Abstract
Background Volutin granules appear to be universally distributed and are morphologically and chemically identical to acidocalcisomes, which are electron-dense granular organelles rich in calcium and phosphate, whose functions include storage of phosphorus and various metal ions, metabolism of polyphosphate, maintenance of intracellular pH, osmoregulation and calcium homeostasis. Prokaryotes are thought to differ from eukaryotes in that they lack membrane-bounded organelles. However, it has been demonstrated that as in acidocalcisomes, the calcium and polyphosphate-rich intracellular "volutin granules (polyphosphate bodies)" in two bacterial species, Agrobacterium tumefaciens, and Rhodospirillum rubrum, are membrane bound and that the vacuolar proton-translocating pyrophosphatases (V-H+PPases) are present in their surrounding membranes. Volutin granules and acidocalcisomes have been found in organisms as diverse as bacteria and humans. Results Here, we show volutin granules also occur in Archaea and are, therefore, present in the three superkingdoms of life (Archaea, Bacteria and Eukarya). Molecular analyses of V-H+PPase pumps, which acidify the acidocalcisome lumen and are diagnostic proteins of the organelle, also reveal the presence of this enzyme in all three superkingdoms suggesting it is ancient and universal. Since V-H+PPase sequences contained limited phylogenetic signal to fully resolve the ancestral nodes of the tree, we investigated the divergence of protein domains in the V-H+PPase molecules. Using Protein family (Pfam) database, we found a domain in the protein, PF03030. The domain is shared by 31 species in Eukarya, 231 in Bacteria, and 17 in Archaea. The universal distribution of the V-H+PPase PF03030 domain, which is associated with the V-H+PPase function, suggests the domain and the enzyme were already present in the Last Universal Common Ancestor (LUCA). Conclusion The importance of the V-H+PPase function and the evolutionary dynamics of these domains support the early origin of the acidocalcisome organelle. In particular, the universality of volutin granules and presence of a functional V-H+PPase domain in the three superkingdoms of life reveals that the acidocalcisomes may have appeared earlier than the divergence of the superkingdoms. This result is remarkable and highlights the possibility that a high degree of cellular compartmentalization could already have been present in the LUCA. Reviewers This article was reviewed by Anthony Poole, Lakshminarayan Iyer and Daniel Kahn
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Affiliation(s)
- Manfredo J Seufferheld
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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103
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Nilsson J, Grahn M, Wright APH. Proteome-wide evidence for enhanced positive Darwinian selection within intrinsically disordered regions in proteins. Genome Biol 2011; 12:R65. [PMID: 21771306 PMCID: PMC3218827 DOI: 10.1186/gb-2011-12-7-r65] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 05/31/2011] [Accepted: 07/19/2011] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Understanding the adaptive changes that alter the function of proteins during evolution is an important question for biology and medicine. The increasing number of completely sequenced genomes from closely related organisms, as well as individuals within species, facilitates systematic detection of recent selection events by means of comparative genomics. RESULTS We have used genome-wide strain-specific single nucleotide polymorphism data from 64 strains of budding yeast (Saccharomyces cerevisiae or Saccharomyces paradoxus) to determine whether adaptive positive selection is correlated with protein regions showing propensity for different classes of structure conformation. Data from phylogenetic and population genetic analysis of 3,746 gene alignments consistently shows a significantly higher degree of positive Darwinian selection in intrinsically disordered regions of proteins compared to regions of alpha helix, beta sheet or tertiary structure. Evidence of positive selection is significantly enriched in classes of proteins whose functions and molecular mechanisms can be coupled to adaptive processes and these classes tend to have a higher average content of intrinsically unstructured protein regions. CONCLUSIONS We suggest that intrinsically disordered protein regions may be important for the production and maintenance of genetic variation with adaptive potential and that they may thus be of central significance for the evolvability of the organism or cell in which they occur.
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Affiliation(s)
- Johan Nilsson
- School of Life Sciences, Södertörn University, SE-141 89 Huddinge, Sweden.
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104
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Overton IM, Graham S, Gould KA, Hinds J, Botting CH, Shirran S, Barton GJ, Coote PJ. Global network analysis of drug tolerance, mode of action and virulence in methicillin-resistant S. aureus. BMC SYSTEMS BIOLOGY 2011; 5:68. [PMID: 21569391 PMCID: PMC3123200 DOI: 10.1186/1752-0509-5-68] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 05/12/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND Staphylococcus aureus is a major human pathogen and strains resistant to existing treatments continue to emerge. Development of novel treatments is therefore important. Antimicrobial peptides represent a source of potential novel antibiotics to combat resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA). A promising antimicrobial peptide is ranalexin, which has potent activity against Gram-positive bacteria, and particularly S. aureus. Understanding mode of action is a key component of drug discovery and network biology approaches enable a global, integrated view of microbial physiology, including mechanisms of antibiotic killing. We developed a systems-wide functional association network approach to integrate proteome and transcriptome profiles, enabling study of drug resistance and mode of action. RESULTS The functional association network was constructed by Bayesian logistic regression, providing a framework for identification of antimicrobial peptide (ranalexin) response modules from S. aureus MRSA-252 transcriptome and proteome profiling. These signatures of ranalexin treatment revealed multiple killing mechanisms, including cell wall activity. Cell wall effects were supported by gene disruption and osmotic fragility experiments. Furthermore, twenty-two novel virulence factors were inferred, while the VraRS two-component system and PhoU-mediated persister formation were implicated in MRSA tolerance to cationic antimicrobial peptides. CONCLUSIONS This work demonstrates a powerful integrative approach to study drug resistance and mode of action. Our findings are informative to the development of novel therapeutic strategies against Staphylococcus aureus and particularly MRSA.
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Affiliation(s)
- Ian M Overton
- Biomedical Systems Analysis, MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.
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105
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Terefe-Ayana D, Yasmin A, Le TL, Kaufmann H, Biber A, Kühr A, Linde M, Debener T. Mining disease-resistance genes in roses: functional and molecular characterization of the rdr1 locus. FRONTIERS IN PLANT SCIENCE 2011; 2:35. [PMID: 22639591 PMCID: PMC3355636 DOI: 10.3389/fpls.2011.00035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/18/2011] [Indexed: 05/03/2023]
Abstract
The interaction of roses with the leaf spot pathogen Diplocarpon rosae (the cause of black spot on roses) is an interesting pathosystem because it involves a long-lived woody perennial, with life history traits very different from most model plants, and a hemibiotrophic pathogen with moderate levels of gene flow. Here we present data on the molecular structure of the first monogenic dominant resistance gene from roses, Rdr1, directed against one isolate of D. rosae. Complete sequencing of the locus carrying the Rdr1 gene resulted in a sequence of 265,477 bp with a cluster of nine highly related TIR-NBS-LRR (TNL) candidate genes. After sequencing revealed candidate genes for Rdr1, we implemented a gene expression analysis and selected five genes out of the nine TNLs. We then silenced the whole TNL gene family using RNAi (Rdr1-RNAi) constructed from the most conserved sequence region and demonstrated a loss of resistance in the normally resistant genotype. To identify the functional TNL gene, we further screened the five TNL candidate genes with a transient leaf infiltration assay. The transient expression assay indicated a single TNL gene (muRdr1H), partially restoring resistance in the susceptible genotype. Rdr1 was found to localize within the muRdr1 gene family; the genes within this locus contain characteristic motifs of active TNL genes and belong to a young cluster of R genes. The transient leaf assay can be used to further analyze the rose black spot interaction and its evolution, extending the analyses to additional R genes and to additional pathogenic types of the pathogen.
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Affiliation(s)
- Diro Terefe-Ayana
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Aneela Yasmin
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Thanh Loan Le
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Helgard Kaufmann
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Anja Biber
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Astrid Kühr
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Marcus Linde
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Thomas Debener
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
- *Correspondence: Thomas Debener, Institute for Plant Genetics, Leibniz University Hannover, Herrenhäuser Str. 2, D-30419 Hannover, Germany. e-mail:
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106
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Reetz MT. Gerichtete Evolution stereoselektiver Enzyme: Eine ergiebige Katalysator‐Quelle für asymmetrische Reaktionen. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201000826] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Manfred T. Reetz
- Max‐Planck‐Institut für Kohlenforschung, Kaiser‐Wilhelm‐Platz 1, 45470 Mülheim an der Ruhr (Deutschland), Fax: (+49) 208‐306‐2985 http://www.mpi‐muelheim.mpg.de/mpikofo_home.html
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107
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Reetz MT. Laboratory Evolution of Stereoselective Enzymes: A Prolific Source of Catalysts for Asymmetric Reactions. Angew Chem Int Ed Engl 2010; 50:138-74. [DOI: 10.1002/anie.201000826] [Citation(s) in RCA: 441] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Manfred T. Reetz
- Max‐Planck‐Institut für Kohlenforschung, Kaiser‐Wilhelm‐Platz 1, 45470 Mülheim an der Ruhr (Germany), Fax: (+49) 208‐306‐2985 http://www.mpi‐muelheim.mpg.de/mpikofo_home.html
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108
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Dietrich JA, McKee AE, Keasling JD. High-throughput metabolic engineering: advances in small-molecule screening and selection. Annu Rev Biochem 2010; 79:563-90. [PMID: 20367033 DOI: 10.1146/annurev-biochem-062608-095938] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabolic engineering for the overproduction of high-value small molecules is dependent upon techniques in directed evolution to improve production titers. The majority of small molecules targeted for overproduction are inconspicuous and cannot be readily obtained by screening. We provide a review on the development of high-throughput colorimetric, fluorescent, and growth-coupled screening techniques, enabling inconspicuous small-molecule detection. We first outline constraints on throughput imposed during the standard directed evolution workflow (library construction, transformation, and screening) and establish a screening and selection ladder on the basis of small-molecule assay throughput and sensitivity. An in-depth analysis of demonstrated screening and selection approaches for small-molecule detection is provided. Particular focus is placed on in vivo biosensor-based detection methods that reduce or eliminate in vitro assay manipulations and increase throughput. We conclude by providing our prospectus for the future, focusing on transcription factor-based detection systems as a natural microbial mode of small-molecule detection.
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Affiliation(s)
- Jeffrey A Dietrich
- UCSF-UCB Joint Graduate Group in Bioengineering, Berkeley, California 94720, USA.
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109
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Chaikam V, Karlson DT. Response and transcriptional regulation of rice SUMOylation system during development and stress conditions. BMB Rep 2010; 43:103-9. [PMID: 20193128 DOI: 10.5483/bmbrep.2010.43.2.103] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Modification of proteins by the reversible covalent addition of the small ubiquitin like modifier (SUMO) protein has important consequences affecting target protein stability, sub-cellular localization, and protein-protein interactions. SUMOylation involves a cascade of enzymatic reactions, which resembles the process of ubiquitination. In this study, we characterized the SUMOylation system from an important crop plant, rice, and show that it responds to cold, salt and ABA stress conditions on a protein level via the accumulation of SUMOylated proteins. We also characterized the transcriptional regulation of individual SUMOylation cascade components during stress and development. During stress conditions, majority of the SUMO cascade components are transcriptionally down regulated. SUMO conjugate proteins and SUMO cascade component transcripts accumulated differentially in various tissues during plant development with highest levels in reproductive tissues. Taken together, these data suggest a role for SUMOylation in rice development and stress responses.
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Affiliation(s)
- Vijay Chaikam
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506-6108, USA
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110
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Grimsrud PA, den Os D, Wenger CD, Swaney DL, Schwartz D, Sussman MR, Ané JM, Coon JJ. Large-scale phosphoprotein analysis in Medicago truncatula roots provides insight into in vivo kinase activity in legumes. PLANT PHYSIOLOGY 2010; 152:19-28. [PMID: 19923235 PMCID: PMC2799343 DOI: 10.1104/pp.109.149625] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 11/11/2009] [Indexed: 05/20/2023]
Abstract
Nitrogen fixation in legumes requires the development of root organs called nodules and their infection by symbiotic rhizobia. Over the last decade, Medicago truncatula has emerged as a major model plant for the analysis of plant-microbe symbioses and for addressing questions pertaining to legume biology. While the initiation of symbiosis and the development of nitrogen-fixing root nodules depend on the activation of a protein phosphorylation-mediated signal transduction cascade in response to symbiotic signals produced by the rhizobia, few sites of in vivo phosphorylation have previously been identified in M. truncatula. We have characterized sites of phosphorylation on proteins from M. truncatula roots, from both whole cell lysates and membrane-enriched fractions, using immobilized metal affinity chromatography and tandem mass spectrometry. Here, we report 3,457 unique phosphopeptides spanning 3,404 nonredundant sites of in vivo phosphorylation on 829 proteins in M. truncatula Jemalong A17 roots, identified using the complementary tandem mass spectrometry fragmentation methods electron transfer dissociation and collision-activated dissociation. With this being, to our knowledge, the first large-scale plant phosphoproteomic study to utilize electron transfer dissociation, analysis of the identified phosphorylation sites revealed phosphorylation motifs not previously observed in plants. Furthermore, several of the phosphorylation motifs, including LxKxxs and RxxSxxxs, have yet to be reported as kinase specificities for in vivo substrates in any species, to our knowledge. Multiple sites of phosphorylation were identified on several key proteins involved in initiating rhizobial symbiosis, including SICKLE, NUCLEOPORIN133, and INTERACTING PROTEIN OF DMI3. Finally, we used these data to create an open-access online database for M. truncatula phosphoproteomic data.
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111
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Joung JG, Corbett AM, Fellman SM, Tieman DM, Klee HJ, Giovannoni JJ, Fei Z. Plant MetGenMAP: an integrative analysis system for plant systems biology. PLANT PHYSIOLOGY 2009; 151:1758-68. [PMID: 19819981 PMCID: PMC2786002 DOI: 10.1104/pp.109.145169] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The information and resources generated from diverse "omics" technologies provide opportunities for producing novel biological knowledge. It is essential to integrate various kinds of biological information and large-scale omics data sets through systematic analysis in order to describe and understand complex biological phenomena. For this purpose, we have developed a Web-based system, Plant MetGenMAP, which can comprehensively integrate and analyze large-scale gene expression and metabolite profile data sets along with diverse biological information. Using this system, significantly altered biochemical pathways and biological processes under given conditions can be retrieved rapidly and efficiently, and transcriptional events and/or metabolic changes in a pathway can be easily visualized. In addition, the system provides a unique function that can identify candidate promoter motifs associated with the regulation of specific biochemical pathways. We demonstrate the functions and application of the system using data sets from Arabidopsis (Arabidopsis thaliana) and tomato (Solanum lycopersicum), respectively. The results obtained by Plant MetGenMAP can aid in a better understanding of the mechanisms that underlie interesting biological phenomena and provide novel insights into the biochemical changes associated with them at the gene and metabolite levels. Plant MetGenMAP is freely available at http://bioinfo.bti.cornell.edu/tool/MetGenMAP.
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112
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Libault M, Joshi T, Benedito VA, Xu D, Udvardi MK, Stacey G. Legume transcription factor genes: what makes legumes so special? PLANT PHYSIOLOGY 2009; 151:991-1001. [PMID: 19726573 PMCID: PMC2773095 DOI: 10.1104/pp.109.144105] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 08/26/2009] [Indexed: 05/18/2023]
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113
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In planta mutagenesis determines the functional regions of the wheat puroindoline proteins. Genetics 2009; 183:853-60. [PMID: 19752217 DOI: 10.1534/genetics.109.106013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In planta analysis of protein function in a crop plant could lead to improvements in understanding protein structure/function relationships as well as selective agronomic or end product quality improvements. The requirements for successful in planta analysis are a high mutation rate, an efficient screening method, and a trait with high heritability. Two ideal targets for functional analysis are the Puroindoline a and Puroindoline b (Pina and Pinb, respectively) genes, which together compose the wheat (Triticum aestivum L.) Ha locus that controls grain texture and many wheat end-use properties. Puroindolines (PINs) together impart soft texture, and mutations in either PIN result in hard seed texture. Studies of the PINs' mode of action are limited by low allelic variation. To create new Pin alleles and identify critical function-determining regions, Pin point mutations were created in planta via EMS treatment of a soft wheat. Grain hardness of 46 unique PIN missense alleles was then measured using segregating F(2):F(3) populations. The impact of individual missense alleles upon PIN function, as measured by grain hardness, ranged from neutral (74%) to intermediate to function abolishing. The percentage of function-abolishing mutations among mutations occurring in both PINA and PINB was higher for PINB, indicating that PINB is more critical to overall Ha function. This is contrary to expectations in that PINB is not as well conserved as PINA. All function-abolishing mutations resulted from structure-disrupting mutations or from missense mutations occurring near the Tryptophan-rich region. This study demonstrates the feasibility of in planta functional analysis of wheat proteins and that the Tryptophan-rich region is the most important region of both PINA and PINB.
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114
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Marz M, Donath A, Verstraete N, Nguyen VT, Stadler PF, Bensaude O. Evolution of 7SK RNA and its protein partners in metazoa. Mol Biol Evol 2009; 26:2821-30. [PMID: 19734296 DOI: 10.1093/molbev/msp198] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
7SK RNA is a key player in the regulation of polymerase II transcription. 7SK RNA was considered as a highly conserved vertebrate innovation. The discovery of poorly conserved homologs in several insects and lophotrochozoans, however, implies a much earlier evolutionary origin. The mechanism of 7SK function requires interaction with the proteins HEXIM and La-related protein 7. Here, we present a comprehensive computational analysis of these two proteins in metazoa, and we extend the collection of 7SK RNAs by several additional candidates. In particular, we describe 7SK homologs in Caenorhabditis species. Furthermore, we derive an improved secondary structure model of 7SK RNA, which shows that the structure is quite well-conserved across animal phyla despite the extreme divergence at sequence level.
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Affiliation(s)
- Manja Marz
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany.
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115
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Teotia S, Lamb RS. The paralogous genes RADICAL-INDUCED CELL DEATH1 and SIMILAR TO RCD ONE1 have partially redundant functions during Arabidopsis development. PLANT PHYSIOLOGY 2009; 151:180-98. [PMID: 19625634 PMCID: PMC2736012 DOI: 10.1104/pp.109.142786] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 07/12/2009] [Indexed: 05/17/2023]
Abstract
RADICAL-INDUCED CELL DEATH1 (RCD1) and SIMILAR TO RCD ONE1 (SRO1) are the only two proteins encoded in the Arabidopsis (Arabidopsis thaliana) genome containing both a putative poly(ADP-ribose) polymerase catalytic domain and a WWE protein-protein interaction domain, although similar proteins have been found in other eukaryotes. Poly(ADP-ribose) polymerases mediate the attachment of ADP-ribose units from donor NAD(+) molecules to target proteins and have been implicated in a number of processes, including DNA repair, apoptosis, transcription, and chromatin remodeling. We have isolated mutants in both RCD1 and SRO1, rcd1-3 and sro1-1, respectively. rcd1-3 plants display phenotypic defects as reported for previously isolated alleles, most notably reduced stature. In addition, rcd1-3 mutants display a number of additional developmental defects in root architecture and maintenance of reproductive development. While single mutant sro1-1 plants are relatively normal, loss of a single dose of SRO1 in the rcd1-3 background increases the severity of several developmental defects, implying that these genes do share some functions. However, rcd1-3 and sro1-1 mutants behave differently in several developmental events and abiotic stress responses, suggesting that they also have distinct functions. Remarkably, rcd1-3; sro1-1 double mutants display severe defects in embryogenesis and postembryonic development. This study shows that RCD1 and SRO1 are at least partially redundant and that they are essential genes for plant development.
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Affiliation(s)
- Sachin Teotia
- Molecular, Cellular, and Developmental Biology Program and Plant Cellular and Molecular Biology Department, Ohio State University, Columbus, Ohio 43210, USA
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116
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KlAft, the Kluyveromyces lactis ortholog of Aft1 and Aft2, mediates activation of iron-responsive transcription through the PuCACCC Aft-type sequence. Genetics 2009; 183:93-106. [PMID: 19581449 DOI: 10.1534/genetics.109.104364] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Iron homeostasis in fungi is regulated at the transcriptional level by two different mechanisms. It is mediated by a conserved GATA-type repressor in most fungi except in the yeast Saccharomyces cerevisiae, where it is controlled by the transcription activators Aft1 and Aft2. These activators are encoded by the paralogous genes AFT1 and AFT2, which result from the whole-genome duplication. Here, we explore regulation of iron homeostasis in the yeast Kluyveromyces lactis that diverged from S. cerevisiae before this event. We identify an ortholog of AFT1/AFT2, designated KlAFT, whose deletion leads to the inability to grow under iron limitation. We show with quantitative real-time PCR analysis that KlAft activates the transcription of all homologs of the Aft1-target genes involved in the iron transport at the cell surface in response to iron limitation. However, homologs of Aft2-specific target genes encoding intracellular iron transporters are regulated neither by KlAft nor by iron. Both bioinformatic and DNA binding and transcription analyses demonstrate that KlAft activates iron-responsive gene expression through the PuCACCC Aft-type sequence. Thus, K. lactis is the first documented species with a positive iron-transcriptional control mediated by only one copy of the Aft-type regulator. This indicates that this function was acquired before the whole-genome duplication and was then diversified into two regulators in S. cerevisiae.
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117
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Siloto RMP, Truksa M, Brownfield D, Good AG, Weselake RJ. Directed evolution of acyl-CoA:diacylglycerol acyltransferase: development and characterization of Brassica napus DGAT1 mutagenized libraries. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:456-61. [PMID: 19195902 DOI: 10.1016/j.plaphy.2008.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 12/26/2008] [Accepted: 12/30/2008] [Indexed: 05/09/2023]
Abstract
Metabolic flux to triacylglycerol (TAG) may be limited by the level of acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) activity. In some species, this enzyme also appears to play a role in the channeling of specific fatty acyl moieties into TAG. The objective of this work is to implement a directed evolution approach to enhance the catalytic efficiency of type-1 DGAT from Brassica napus (BnDGAT1). We generated randomly mutagenized libraries of BnDGAT1 in a yeast expression vector using error-prone PCR. The mutagenized libraries were used to transform a Saccharomyces cerevisiae strain devoid of neutral lipid biosynthesis and analyzed using a high-throughput screening (HTS) system. The HTS, recently developed for this purpose, consisted of a positive selection of clones expressing active DGAT mutants followed by quantification of DGAT activity by fluorescence detection of TAG in yeast cells. The initial results indicated that the positive selection system efficiently eliminated DGAT mutants lacking enzyme activity. Screening of 1528 selected mutants revealed that some DGAT clones had enhanced ability to synthesize TAG in yeast. This was confirmed by analysis of individual clones that could carry mutations resulting in an increased catalytic efficiency. The directed evolution approach could lead to the development of an improved plant DGAT1 for increasing seed oil content in oleaginous crops.
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Affiliation(s)
- Rodrigo M P Siloto
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, AB, Canada
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118
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Abstract
There exist four fundamentally different classes of membrane-bound transport proteins: ion channels; transporters; aquaporins; and ATP-powered pumps. ATP-binding cassette (ABC) transporters are an example of ATP-dependent pumps. ABC transporters are ubiquitous membrane-bound proteins, present in all prokaryotes, as well as plants, fungi, yeast and animals. These pumps can move substrates in (influx) or out (efflux) of cells. In mammals, ABC transporters are expressed predominantly in the liver, intestine, blood-brain barrier, blood-testis barrier, placenta and kidney. ABC proteins transport a number of endogenous substrates, including inorganic anions, metal ions, peptides, amino acids, sugars and a large number of hydrophobic compounds and metabolites across the plasma membrane, and also across intracellular membranes. The human genome contains 49 ABC genes, arranged in eight subfamilies and named via divergent evolution. That ABC genes are important is underscored by the fact that mutations in at least I I of these genes are already known to cause severe inherited diseases (eg cystic fibrosis and X-linked adrenoleukodystrophy [X-ALD]). ABC transporters also participate in the movement of most drugs and their metabolites across cell surface and cellular organelle membranes; thus, defects in these genes can be important in terms of cancer therapy, pharmacokinetics and innumerable pharmacogenetic disorders.
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Affiliation(s)
- Vasilis Vasiliou
- Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO 80045, USA
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119
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Lehti-Shiu MD, Zou C, Hanada K, Shiu SH. Evolutionary history and stress regulation of plant receptor-like kinase/pelle genes. PLANT PHYSIOLOGY 2009; 150:12-26. [PMID: 19321712 PMCID: PMC2675737 DOI: 10.1104/pp.108.134353] [Citation(s) in RCA: 275] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Receptor-Like Kinase (RLK)/Pelle genes play roles ranging from growth regulation to defense response, and the dramatic expansion of this family has been postulated to be crucial for plant-specific adaptations. Despite this, little is known about the history of or the factors that contributed to the dramatic expansion of this gene family. In this study, we show that expansion coincided with the establishment of land plants and that RLK/Pelle subfamilies were established early in land plant evolution. The RLK/Pelle family expanded at a significantly higher rate than other kinases, due in large part to expansion of a few subfamilies by tandem duplication. Interestingly, these subfamilies tend to have members with known roles in defense response, suggesting that their rapid expansion was likely a consequence of adaptation to fast-evolving pathogens. Arabidopsis (Arabidopsis thaliana) expression data support the importance of RLK/Pelles in biotic stress response. We found that hundreds of RLK/Pelles are up-regulated by biotic stress. Furthermore, stress responsiveness is correlated with the degree of tandem duplication in RLK/Pelle subfamilies. Our findings suggest a link between stress response and tandem duplication and provide an explanation for why a large proportion of the RLK/Pelle gene family is found in tandem repeats. In addition, our findings provide a useful framework for potentially predicting RLK/Pelle stress functions based on knowledge of expansion pattern and duplication mechanism. Finally, we propose that the detection of highly variable molecular patterns associated with specific pathogens/parasites is the main reason for the up-regulation of hundreds of RLK/Pelles under biotic stress.
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Affiliation(s)
- Melissa D Lehti-Shiu
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
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120
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Calculating complexity of large randomized libraries. J Theor Biol 2009; 259:641-5. [PMID: 19376134 DOI: 10.1016/j.jtbi.2009.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 04/08/2009] [Accepted: 04/09/2009] [Indexed: 01/21/2023]
Abstract
Randomized libraries are increasingly popular in protein engineering and other biomedical research fields. Statistics of the libraries are useful to guide and evaluate randomized library construction. Previous works only give the mean of the number of unique sequences in the library, and they can only handle equal molar ratio of the four nucleotides at a small number of mutation sites. We derive formulas to calculate the mean and variance of the number of unique sequences in libraries generated by cassette mutagenesis with mixtures of arbitrary nucleotide ratios. Computer program was developed which utilizes arbitrary numerical precision software package to calculate the statistics of large libraries. The statistics of library with mutations in more than 20 amino acids can be calculated easily. Results show that the nucleotide ratios have significant effects on these statistics. The more skewed the ratio, the larger the library size is needed to obtain the same expected number of unique sequences. The program is freely available at http://graphics.med.yale.edu/cgi-bin/lib_comp.pl.
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121
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Chandran D, Tai YC, Hather G, Dewdney J, Denoux C, Burgess DG, Ausubel FM, Speed TP, Wildermuth MC. Temporal global expression data reveal known and novel salicylate-impacted processes and regulators mediating powdery mildew growth and reproduction on Arabidopsis. PLANT PHYSIOLOGY 2009; 149:1435-51. [PMID: 19176722 PMCID: PMC2649394 DOI: 10.1104/pp.108.132985] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 01/23/2009] [Indexed: 05/20/2023]
Abstract
Salicylic acid (SA) is a critical mediator of plant innate immunity. It plays an important role in limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis (Arabidopsis thaliana). To investigate this later phase of the PM interaction and the role played by SA, we performed replicated global expression profiling for wild-type and SA biosynthetic mutant isochorismate synthase1 (ics1) Arabidopsis from 0 to 7 d after infection. We found that ICS1-impacted genes constitute 3.8% of profiled genes, with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T(2) statistic). Functional analyses of T(2)-selected genes identified statistically significant PM-impacted processes, including photosynthesis, cell wall modification, and alkaloid metabolism, that are ICS1 independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also support a role for ICS1 (SA) in iron and calcium homeostasis and identify components of SA cross talk with other phytohormones. Through our analysis, 39 novel PM-impacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2 (for plant ubiquitin regulatory X domain-containing protein 2), results in significantly reduced reproduction of the PM in a cell death-independent manner. Although little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48, an essential AAA-ATPase chaperone that mediates diverse cellular activities, including homotypic fusion of endoplasmic reticulum and Golgi membranes, endoplasmic reticulum-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance.
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Affiliation(s)
- Divya Chandran
- Department of Plant and Microbial Biology , University of California, Berkeley, California 94720, USA
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122
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Shivange AV, Marienhagen J, Mundhada H, Schenk A, Schwaneberg U. Advances in generating functional diversity for directed protein evolution. Curr Opin Chem Biol 2009; 13:19-25. [DOI: 10.1016/j.cbpa.2009.01.019] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 01/26/2009] [Accepted: 01/28/2009] [Indexed: 11/16/2022]
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123
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Reetz MT, Kahakeaw D, Sanchis J. Shedding light on the efficacy of laboratory evolution based on iterative saturation mutagenesis. ACTA ACUST UNITED AC 2009; 5:115-22. [DOI: 10.1039/b814862g] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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124
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Blanié S, Mortier J, Delverdier M, Bertagnoli S, Camus-Bouclainville C. M148R and M149R are two virulence factors for myxoma virus pathogenesis in the European rabbit. Vet Res 2008; 40:11. [PMID: 19019281 PMCID: PMC2695013 DOI: 10.1051/vetres:2008049] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 11/13/2008] [Indexed: 11/24/2022] Open
Abstract
Myxoma virus (MYXV), a member of the Poxviridae family, is the agent responsible for myxomatosis, a fatal disease in the European rabbit (Oryctolagus cuniculus). MYXV has a linear double-stranded DNA genome that encodes several factors important for evasion from the host immune system. Among them, four ankyrin (ANK) repeat proteins were identified: M148R, M149R, M150R and M-T5. To date, only M150R and M-T5 were studied and characterized as critical virulence factors. This article presents the first characterization of M148R and M149R. Green Fluorescent Protein (GFP) fusions allowed us to localize them in a viral context. Whereas M149R is only cytoplasmic, interestingly, M148R is in part located in the nucleolus, a unique feature for an ANK repeat poxviral protein. In order to evaluate their implication in viral pathogenicity, targeted M148R, M149R, or both deletions were constructed in the wild type T1 strain of myxoma virus. In vitro infection of rabbit and primate cultured cells as well as primary rabbit cells allowed us to conclude that M148R and M149R are not likely to be implicated in cell tropism or host range functions. However, in vivo experiments revealed that they are virulence factors since after infection of European rabbits with mutant viruses, a delay in the onset of clinical signs, an increase of survival time and a dramatic decrease in mortality rate were observed. Moreover, histological analysis suggests that M148R plays a role in the subversion of host inflammatory response by MYXV.
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125
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Wang Y, Ladunga I, Miller AR, Horken KM, Plucinak T, Weeks DP, Bailey CP. The small ubiquitin-like modifier (SUMO) and SUMO-conjugating system of Chlamydomonas reinhardtii. Genetics 2008; 179:177-92. [PMID: 18493050 PMCID: PMC2390597 DOI: 10.1534/genetics.108.089128] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 03/27/2008] [Indexed: 11/18/2022] Open
Abstract
The availability of the complete DNA sequence of the Chlamydomonas reinhardtii genome and advanced computational biology tools has allowed elucidation and study of the small ubiquitin-like modifier (SUMO) system in this unicellular photosynthetic alga and model eukaryotic cell system. SUMO is a member of a ubiquitin-like protein superfamily that is covalently attached to target proteins as a post-translational modification to alter the localization, stability, and/or function of the target protein in response to changes in the cellular environment. Three SUMO homologs (CrSUMO96, CrSUMO97, and CrSUMO148) and three novel SUMO-related proteins (CrSUMO-like89A, CrSUMO-like89B, and CrSUMO-like90) were found by diverse gene predictions, hidden Markov models, and database search tools inferring from Homo sapiens, Saccharomyces cerevisiae, and Arabidopsis thaliana SUMOs. Among them, CrSUMO96, which can be recognized by the A. thaliana anti-SUMO1 antibody, was studied in detail. Free CrSUMO96 was purified by immunoprecipitation and identified by mass spectrometry analysis. A SUMO-conjugating enzyme (SCE) (E2, Ubc9) in C. reinhardtii was shown to be functional in an Escherichia coli-based in vivo chimeric SUMOylation system. Antibodies to CrSUMO96 recognized free and conjugated forms of CrSUMO96 in Western blot analysis of whole-cell extracts and nuclear localized SUMOylated proteins with in situ immunofluorescence. Western blot analysis showed a marked increase in SUMO conjugated proteins when the cells were subjected to environmental stresses, such as heat shock and osmotic stress. Related analyses revealed multiple potential ubiquitin genes along with two Rub1 genes and one Ufm1 gene in the C. reinhardtii genome.
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Affiliation(s)
- Ying Wang
- Department of Biochemistry and Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0664, USA
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126
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Reetz MT, Wu S. Greatly reduced amino acid alphabets in directed evolution: making the right choice for saturation mutagenesis at homologous enzyme positions. Chem Commun (Camb) 2008:5499-501. [DOI: 10.1039/b813388c] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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