scholarly journals Identification of Leishmania genes encoding proteins containing tandemly repeating peptides.

1987 ◽  
Vol 166 (6) ◽  
pp. 1814-1824 ◽  
Author(s):  
A E Wallis ◽  
W R McMaster
Keyword(s):  
Amino Acids ◽  
Fusion Protein ◽  
Immune Evasion ◽  
Leishmania Major ◽  
Protein Antigens ◽  
Expression Library ◽  
Intracellular Parasites ◽  
Encoded Proteins ◽  
Genes Encoding

A genomic Leishmania major DNA expression library was screened using antibodies raised against L. major membranes. Two different clones were identified that encoded proteins containing regions of tandemly repeated peptides. Clone 20 encodes a repetitive peptide of 14 amino acids, while clone 39 encodes a repetitive peptide of 10 amino acids. DNA from clone 20 hybridized with two RNA species of 9,500 and 5,200 nucleotides in length, while DNA from clone 39 hybridized to a single RNA species of 7,500 nucleotides. Antibodies against clone 20 fusion protein recognized a series of L. major proteins of apparent mol wt 250,000. Regions of repetitive peptides is a characteristic shared by many malarial protein antigens and this feature has been implicated in immune evasion. Intracellular parasites such as Leishmania and Plasmodia, therefore, may have evolved similar mechanisms consisting of the expression of proteins containing tandemly repeating peptides that are involved in immune evasion.

scholarly journals Untargeted Metabolomics Uncovers the Essential Lysine Transporter in Toxoplasma gondii

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 476
Author(s):  
Joachim Kloehn ◽  
Matteo Lunghi ◽  
Emmanuel Varesio ◽  
David Dubois ◽  
Dominique Soldati-Favre
Keyword(s):  
Amino Acids ◽  
Toxoplasma Gondii ◽  
Rna Degradation ◽  
Major Facilitator Superfamily ◽  
Untargeted Metabolomics ◽  
Apicomplexan Parasites ◽  
Obligate Intracellular ◽  
Intracellular Parasites ◽  
Major Facilitator ◽  
Plasma Membrane Transporter

Apicomplexan parasites are responsible for devastating diseases, including malaria, toxoplasmosis, and cryptosporidiosis. Current treatments are limited by emerging resistance to, as well as the high cost and toxicity of existing drugs. As obligate intracellular parasites, apicomplexans rely on the uptake of many essential metabolites from their host. Toxoplasma gondii, the causative agent of toxoplasmosis, is auxotrophic for several metabolites, including sugars (e.g., myo-inositol), amino acids (e.g., tyrosine), lipidic compounds and lipid precursors (cholesterol, choline), vitamins, cofactors (thiamine) and others. To date, only few apicomplexan metabolite transporters have been characterized and assigned a substrate. Here, we set out to investigate whether untargeted metabolomics can be used to identify the substrate of an uncharacterized transporter. Based on existing genome- and proteome-wide datasets, we have identified an essential plasma membrane transporter of the major facilitator superfamily in T. gondii—previously termed TgApiAT6-1. Using an inducible system based on RNA degradation, TgApiAT6-1 was depleted, and the mutant parasite’s metabolome was compared to that of non-depleted parasites. The most significantly reduced metabolite in parasites depleted in TgApiAT6-1 was identified as the amino acid lysine, for which T. gondii is predicted to be auxotrophic. Using stable isotope-labeled amino acids, we confirmed that TgApiAT6-1 is required for efficient lysine uptake. Our findings highlight untargeted metabolomics as a powerful tool to identify the substrate of orphan transporters.

Targeted gene deletion of Leishmania major genes encoding developmental stage-specific leishmanolysin (GP63)

1998 ◽  
Vol 27 (3) ◽  
pp. 519-530 ◽  
Author(s):  
Phalgun B. Joshi ◽  
David L. Sacks ◽  
Govind Modi ◽  
W. Robert McMaster
Keyword(s):  
Developmental Stage ◽  
Gene Deletion ◽  
Leishmania Major ◽  
Major Genes ◽  
Targeted Gene Deletion ◽  
Genes Encoding

Identification and isolation of the gene encoding the small subunit of ribonucleotide reductase from Saccharomyces cerevisiae: DNA damage-inducible gene required for mitotic viability

1987 ◽  
Vol 7 (8) ◽  
pp. 2783-2793
Author(s):  
S J Elledge ◽  
R W Davis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Dna Damage ◽  
Ribonucleotide Reductase ◽  
Small Subunit ◽  
Cross Reaction ◽  
Expression Library ◽  
Gene Encoding ◽  
Ribonucleotide Reductases ◽  
Colony Color

Ribonucleotide reductase catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. The gene encoding the small subunit of ribonucleotide reductase was isolated from a Saccharomyces cerevisiae genomic DNA expression library in lambda gt11 by a fortuitous cross-reaction with anti-RecA antibodies. The cross-reaction was due to an identity between the last four amino acids of each protein. The gene has been named RNR2 and is centromere linked on chromosome X. The nucleotide sequence was determined, and the deduced amino acid sequence, 399 amino acids, shows extensive homology with other eucaryotic ribonucleotide reductases. Transplason mutagenesis was used to disrupt the RNR2 gene. A novel assay using colony color sectoring was developed to demonstrate visually that RNR2 is essential for mitotic viability. RNR2 encodes a 1.5-kilobase mRNA whose levels increase 18-fold after treatment with the DNA-damaging agent 4-nitroquinoline 1-oxide. CDC8 was also found to be inducible by DNA damage, but POL1 and URA3 were not inducible by 4-nitroquinoline 1-oxide. The expression of these genes defines a new mode of regulation for enzymes involved in DNA biosynthesis and sharpens our picture of the events leading to DNA repair in eucaryotic cells.

Acquisition of NFKB1-selective DNA binding by substitution of four amino acid residues from NFKB1 into RelA

1993 ◽  
Vol 13 (7) ◽  
pp. 3850-3859
Author(s):  
T A Coleman ◽  
C Kunsch ◽  
M Maher ◽  
S M Ruben ◽  
C A Rosen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dna Binding ◽  
Fusion Protein ◽  
Binding Specificity ◽  
Single Amino Acid ◽  
Nf Kappa B ◽  
Dna Binding Specificity ◽  
Dna Motif ◽  
Single Amino Acid Change

The subunits of NF-kappa B, NFKB1 (formerly p50) and RelA (formerly p65), belong to a growing family of transcription factors that share extensive similarity to the c-rel proto-oncogene product. The homology extends over a highly conserved stretch of approximately 300 amino acids termed the Rel homology domain (RHD). This region has been shown to be involved in both multimerization (homo- and heterodimerization) and DNA binding. It is now generally accepted that homodimers of either subunit are capable of binding DNA that contains a kappa B site originally identified in the immunoglobulin enhancer. Recent studies have demonstrated that the individual subunits of the NF-kappa B transcription factor complex can be distinguished by their ability to bind distinct DNA sequence motifs. By using NFKB1 and RelA subunit fusion proteins, different regions within the RHD were found to confer DNA-binding and multimerization functions. A fusion protein that contains 34 N-terminal amino acids of NFKB1 and 264 amino acids of RelA displayed preferential binding to an NFKB1-selective DNA motif while dimerizing with the characteristics of RelA. Within the NFKB1 portion of this fusion protein, a single amino acid change of His to Arg altered the DNA-binding specificity to favor interaction with the RelA-selective DNA motif. Furthermore, substitution of four amino acids from NFKB1 into RelA was able to alter the DNA-binding specificity of the RelA protein to favor interaction with the NFKB1-selective site. Taken together, these findings demonstrate the presence of a distinct subdomain within the RHD involved in conferring the DNA-binding specificity of the Rel family of proteins.

scholarly journals The Bartonella vinsonii subsp. arupensis Immunodominant Surface Antigen BrpA Gene, Encoding a 382-Kilodalton Protein Composed of Repetitive Sequences, Is a Member of a Multigene Family Conserved among Bartonella Species

2005 ◽  
Vol 73 (5) ◽  
pp. 3128-3136 ◽  
Author(s):  
Robert D. Gilmore ◽  
Travis M. Bellville ◽  
Steven L. Sviat ◽  
Michael Frace
Keyword(s):  
Bartonella Henselae ◽  
Repetitive Sequences ◽  
Expression Library ◽  
Gene Encoding ◽  
Significant Similarity ◽  
Bartonella Quintana ◽  
Genomic Expression ◽  
Genes Encoding ◽  
Multiple Regions ◽  
Adhesin Protein

ABSTRACT Bartonella proteins that elicit an antibody response during an infection are poorly defined; therefore, to characterize antigens recognized by the host, a Bartonella genomic expression library was screened with serum from an infected mouse. This process led to the discovery of a Bartonella vinsonii subsp. arupensis gene encoding a 382-kDa protein, part of a gene family encoding large proteins, each containing multiple regions of repetitive segments. The genes were termed brpA to -C (bartonella repeat protein) and bore significant similarity to genes encoding the BadA adhesin protein and members of the variably expressed outer membrane protein family of proteins from Bartonella henselae and Bartonella quintana, respectively.

Kinetics of release of amino acids by Leishmania major

1999 ◽  
Vol 103 (1) ◽  
pp. 101-104 ◽  
Author(s):  
J.Joseph Blum ◽  
Z.Ioav Cabantchik ◽  
Lita Vieira
Keyword(s):  
Amino Acids ◽  
Leishmania Major ◽  
Kinetics Of

Consistency and Change

2019 ◽  
Author(s):  
Alan Kelly
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Living Organism ◽  
Peptide Bond ◽  
The Body ◽  
Blood Proteins ◽  
Genes Encoding ◽  
Fundamental Phenomenon ◽  
P Proteins

Proteins are, in my view, the most impressive molecules in food. They influence the texture, crunch, chew, flow, color, flavor, and nutritional quality of food. Not only that, but they can radically change their properties and how they behave depending on the environment and, critically for food, in response to processes like heating. Even when broken down into smaller components they are important, for example giving cheese many of its critical flavor notes. Indeed, I would argue that perhaps the most fundamental phenomenon we encounter in cooking or processing food is the denaturation of proteins, as will be explained shortly. Beyond food, the value of proteins and their properties is widespread across biology. Many of the most significant molecules in our body and that of any living organism (including plants and animals) are proteins. These include those that make hair and skin what they are, as well as the hemoglobin that transports oxygen around the body in our blood. Proteins are built from amino acids, a family of 20 closely related small molecules, which all have in chemical terms the same two ends (chemically speaking, an amino end and an acidic end, hence the name) but differ in the middle. This bit in the middle varies from amino acid to amino acid, from simple (a hydrogen atom in the case of glycine, the simplest amino acid) to much more complex structures. Amino acids can link up very neatly, as the amino end of one can form a bond (called a peptide bond) with the acid end of another, and so forth, so that chains of amino acids are formed that, when big enough (more than a few dozen amino acids), we call proteins. Our bodies produce thousands of proteins for different functions, and the instructions for which amino acids combine to make which proteins are essentially what the genetic code encrypted in our DNA specifies. We hear a lot about our genes encoding the secrets of life, but what that code spells is basically P-R-O-T-E-I-N. Yes, these are very important molecules!

scholarly journals Transcriptomic Analysis of Staphylococcus xylosus in Solid Dairy Matrix Reveals an Aerobic Lifestyle Adapted to Rind

2020 ◽  
Vol 8 (11) ◽  
pp. 1807
Author(s):  
Sabine Leroy ◽  
Sergine Even ◽  
Pierre Micheau ◽  
Anne de La Foye ◽  
Valérie Laroute ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Antioxidant Enzymes ◽  
Dairy Products ◽  
Molecular Mechanisms ◽  
Iron Acquisition ◽  
Carbon Sources ◽  
Original System ◽  
Staphylococcus Xylosus ◽  
Genes Encoding

Staphylococcus xylosus is found in the microbiota of traditional cheeses, particularly in the rind of soft smeared cheeses. Despite its frequency, the molecular mechanisms allowing the growth and adaptation of S. xylosus in dairy products are still poorly understood. A transcriptomic approach was used to determine how the gene expression profile is modified during the fermentation step in a solid dairy matrix. S. xylosus developed an aerobic metabolism perfectly suited to the cheese rind. It overexpressed genes involved in the aerobic catabolism of two carbon sources in the dairy matrix, lactose and citrate. Interestingly, S. xylosus must cope with nutritional shortage such as amino acids, peptides, and nucleotides, consequently, an extensive up-regulation of genes involved in their biosynthesis was observed. As expected, the gene sigB was overexpressed in relation with general stress and entry into the stationary phase and several genes under its regulation, such as those involved in transport of anions, cations and in pigmentation were up-regulated. Up-regulation of genes encoding antioxidant enzymes and glycine betaine transport and synthesis systems showed that S. xylosus has to cope with oxidative and osmotic stresses. S. xylosus expressed an original system potentially involved in iron acquisition from lactoferrin.

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