Primary structure, expression and localization of two intermediate subunit lectins ofEntamoeba disparthat contain multiple CXXC motifs

Parasitology ◽  
2007 ◽  
Vol 134 (14) ◽  
pp. 1989-1999 ◽  
Author(s):  
H. TACHIBANA ◽  
X.-J. CHENG ◽  
S. KOBAYASHI ◽  
Y. OKADA ◽  
J. ITOH ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Confocal Microscopy ◽  
Phenotypic Expression ◽  
Surface Proteins ◽  
Rt Pcr ◽  
Entamoeba Dispar ◽  
Genes Encoding ◽  
Sequence Identities

SUMMARYWe have recently identified 2 surface proteins inEntamoeba histolyticaas intermediate subunits of galactose- andN-acetyl-D-galactosamine-inhibitable lectin (EhIgl1 and EhIgl2); these proteins both contain multiple CXXC motifs. Here, we report the molecular characterization of the corresponding proteins inEntamoeba dispar, which is neither pathogenic nor invasive. TwoIglgenes encoding 1110 and 1106 amino acids (EdIgl1 and EdIgl2) were cloned from 2 strains ofE. dispar. The amino acid sequence identities were 79% between EdIgl1 and EdIgl2, 75–76% between EdIgl1 and EhIgl1, and 73–74% between EdIgl2 and EhIgl2. However, all the CXXC motifs were conserved in the EdIgl proteins, suggesting that the fold conferred by this motif is important for function. Comparison of the expression level of theIglgenes by real-time RT-PCR showed 3–5 times higher expression ofEdIgl1compared toEdIgl2. Most EdIgl1 and EdIgl2 proteins were co-localized on the surface and in the cytoplasm of trophozoites, based on confocal microscopy. However, a different localization of EdIgl1 and EdIgl2 in intracellular vacuoles and a different level of phenotypic expression of the two Igls were also observed. These results demonstrate that Igls are important proteins even in non-pathogenic amoeba and that Igl1 and Igl2 may possess different functions.

scholarly journals Avoided motifs: short amino acid strings missing from protein datasets

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Function ◽  
Large Protein ◽  
New Approach ◽  
Cellular Context ◽  
Human Proteins ◽  
Context Specific ◽  
Protein Datasets

Abstract According to the amino acid composition of natural proteins, it could be expected that all possible sequences of three or four amino acids will occur at least once in large protein datasets purely by chance. However, in some species or cellular context, specific short amino acid motifs are missing due to unknown reasons. We describe these as Avoided Motifs, short amino acid combinations missing from biological sequences. Here we identify 209 human and 154 bacterial Avoided Motifs of length four amino acids, and discuss their possible functionality according to their presence in other species. Furthermore, we determine two Avoided Motifs of length three amino acids in human proteins specifically located in the cytoplasm, and two more in secreted proteins. Our results support the hypothesis that the characterization of Avoided Motifs in particular contexts can provide us with information about functional motifs, pointing to a new approach in the use of molecular sequences for the discovery of protein function.

Characterization of an isozyme of S-adenosylmethionine synthetase from rat liver

1984 ◽  
Vol 62 (5) ◽  
pp. 276-279 ◽  
Author(s):  
C. H. Lin ◽  
W. Chung ◽  
K. P. Strickland ◽  
A. J. Hudson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Enzymatic Synthesis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Aromatic Amino Acids ◽  
Adenosylmethionine Synthetase ◽  
Cellulose Column

An isozyme of S-adenosylmethionine synthetase has been purified to homogeneity by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and gel filtration on a Sephadex G-200 column. The purified enzyme is very unstable and has a molecular weight of 120 000 consisting of two identical subunits. Amino acid analysis on the purified enzyme showed glycine, glutamate, and aspartate to be the most abundant and the aromatic amino acids to be the least abundant. It possesses tripolyphosphatase activity which can be stimulated five to six times by S-adenosylmethionine (20–40 μM). The findings support the conclusion that an enzyme-bound tripolyphosphate is an obligatory intermediate in the enzymatic synthesis of S-adenosylmethionine from ATP and methionine.

scholarly journals Characterization of the 6'-N-aminoglycoside acetyltransferase gene aac(6')-Im [corrected] associated with a sulI-type integron.

1997 ◽  
Vol 41 (2) ◽  
pp. 314-318 ◽  
Author(s):  
E Hannecart-Pokorni ◽  
F Depuydt ◽  
L de wit ◽  
E van Bossuyt ◽  
J Content ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Resistance Gene ◽  
Citrobacter Freundii ◽  
Gram Negative ◽  
Gene Environment ◽  
Insert Region ◽  
Klebsiella Spp

The amikacin resistance gene aac(6')-Im [corrected] from Citrobacter freundii Cf155 encoding an aminoglycoside 6'-N-acetyltransferase was characterized. The gene was identified as a coding sequence of 521 bp located down-stream from the 5' conserved segment of an integron. The sequence of this aac(6')-Im [corrected] gene corresponded to a protein of 173 amino acids which possessed 64.2% identity in a 165-amino-acid overlap with the aac(6')-Ia gene product (F.C. Tenover, D. Filpula, K.L. Phillips, and J. J. Plorde, J. Bacteriol. 170:471-473, 1988). By using PCR, the aac(6')-Im [corrected] gene could be detected in 8 of 86 gram-negative clinical isolates from two Belgian hospitals, including isolates of Citrobacter, Klebsiella spp., and Escherichia coli. PCR mapping of the aac(6')-Im [corrected] gene environment in these isolates indicated that the gene was located within a sulI-type integron; the insert region is 1,700 bases long and includes two genes cassettes, the second being ant (3")-Ib.

Structural characterization of folded and extended conformations in peptides containing γ amino acids with proteinogenic side chains: crystal structures of γn, (αγ)n and γγδγ sequences

2015 ◽  
Vol 39 (5) ◽  
pp. 3319-3326 ◽  
Author(s):  
Madhusudana M. B. Reddy ◽  
K. Basuroy ◽  
S. Chandrappa ◽  
B. Dinesh ◽  
B. Vasantha ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crystal Structures ◽  
Structural Characterization ◽  
Side Chains ◽  
Amino Acid Residues

γn amino acid residues can be incorporated into structures in γn and hybrid sequences containing folded and extended α and δ residues.

Isolation and partial characterization of amphibian tyrosine oxidase polysomes

Development ◽  
1970 ◽  
Vol 24 (1) ◽  
pp. 109-118
Author(s):  
E. L. Triplett ◽  
R. Herzog ◽  
L. P. Russell
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Enzymic Activity ◽  
Antigenic Determinants ◽  
Free System ◽  
A Cell ◽  
Generating System ◽  
Soluble Components

A population of polysomes isolated from frogskinis capable of supporting protein synthesis in a cell-free system containing an energy generating system, ‘soluble components’, and amino acids. These polysomes catalyse the oxidation of DOPA after gentle trypsinization, and they also have antigenic determinants attributable to tyrosine oxidase. Skin polysomes sedimented in 10–30 % sucrose gradients contain tyrosine oxidase peaks of enzymic activity at the bottom and top of the tube and in the 250 S regions. A peak of tyrosine oxidase antigenic acitvity is found in the 250–350S region of the gradient. Polysomes resolved on the gradient retain the ability to support protein synthesis in a cellfree system. All 250–350S particles capable of supporting the incorporation of [14C]amino acid into tyrosine oxidase are precipitable with tyrosine oxidase antibodies. It is probable that 250–350S tyrosine oxidase antibody precipitates contain only polysomes for this protein.

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!

MUTANT AND CHIMAERIC RECOMBINANT PLASMINOGEN ACTIVATORS

1987 ◽  
Author(s):  
L Piérard ◽  
P Jacobs ◽  
D Gheysen ◽  
M Hoylaerts ◽  
A Cravador ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasminogen Activators ◽  
Tissue Type ◽  
Single Chain ◽  
Type Plasminogen Activator ◽  
Genes Encoding ◽  
A Chain ◽  
Mutant Forms ◽  
Kringle 2

In order to produce plasminogen activators (PA) more specific and more active than their natural counterparts, we designed recombinant genes encoding mutant forms of urokinase (u-PA) and chimaeric molecules combining fragments of tissue type plasminogen activator (t-PA) and of u-PA. The following constructs have been realized : 1°) u-PA where amino acids Arg156 and Lys158 have been replaced by Thr. The purpose of this approach was to obtain a prourokinase molecule displaying similar properties as the natural single chain urokinase (scu-PA) but resistant to the cleavage by plasmin ; 2°) u-PA where the second cleavage site, Lys135-Lys136, was also eliminated either by replacing amino acid 132 to amino acid 147 by a shorter link (Ser-Thr) as found in t-PA, or by replacing the two lysines by glutamine residues. The resulting molecules correspond thus to completely uncleavable scu-PA forms ; 3°) an hybrid composed of the finger domain of t-PA and of the B-chain of u-PA ; 4°) an hybrid made of the A-chain of t-PA and of the B-chain of u-PA ; 5°) an hybrid where the kringle 2 of t-PA has been inserted between the kringle domain and the B-chain of u-PA. The last three constructs have been made to confer the fibrin binding specificity of t-PA to the B-chain of u-PA.All recombinant DNAs were introduced, via an expression vector, into R1610 and CosI cells. Secretion of the recombinant products was monitored by ELISA and activities were assayed in an immobilized system involving a monoclonal antibody (AAU2) raised against 33K u-PA, plasminogen and the specific chromogenic substrate S2251. In this assay, all recombinant products, except the plasmin resistant (156-158) scu-PA, showed apparent specific activities comparable to the activity of natural two-chain u-PA. Potential interest of these new plasminogen activators in therapy will be discussed and further characterization of the new molecules will-be presented.

Molecular Characterization of Genes Coding for Wild-Type and Sulfonylurea-Resistant Acetolactate Synthase in the Cyanobacterium Synechococcus PC C7942

1990 ◽  
Vol 45 (5) ◽  
pp. 538-543 ◽  
Author(s):  
D. Friedberg ◽  
J. Seijffers
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Molecular Characterization ◽  
Amino Acid Level ◽  
Acetolactate Synthase ◽  
Mutant Gene ◽  
Wild Type ◽  
E Coli

We present here the isolation and molecular characterization of acetolactate synthase (ALS) genes from the cyanobacterium Synechococcus PCC7942 which specify a sulfonylurea-sensitive enzyme and from the sulfonylurea-resistant mutant SM3/20, which specify resistance to sulfonylurea herbicides. The ALS gene was cloned and mapped by complementation of an Escherichia coli ilv auxotroph that requires branched-chain amino acids for growth and lacks ALS activity. The cyanobacterial gene is efficiently expressed in this heterologous host. The ALS gene codes for 612 amino acids and shows high sequence homology (46%) at the amino acid level with ALS III of E. coli and with the tobacco ALS. The resistant phenotype is a consequence of proline to serine substitution in residue 115 of the deduced amino acid sequence. Functional expression of the mutant gene in wild-type Synechococcus and in E. coli confirmed that this amino-acid substitution is responsible for the resistance. Yet the deduced amino-acid sequence as compared with othjer ALS proteins supports the notion that the amino-acid context of the substitution is important for the resistance.

Molecular characterization of MHC class II DRA cDNA in Deoni cattle

2018 ◽  
Author(s):  
K. Swathi ◽  
M. Gnana Prakash ◽  
D. Sakaram ◽  
T. Raghunandan ◽  
A. Sarat Chandra ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mhc Class Ii ◽  
Signal Peptide ◽  
Class Ii ◽  
Glycosylation Site ◽  
Amino Acid Sequences ◽  
Conserved Residues ◽  
A2 Domain

The present study was undertaken to clone and characterize DRA gene in Deoni cattle. The cDNA for the DRA gene was amplified by using specific primers designed based on available cattle sequences and purified products were cloned in competent E.coli (DH5á) strain. The full length 1013bp product of cDNA of DRA contained a single ORF of 762 nucleotides that coded for 253 amino acids translated product. Twenty four amino acids formed signal peptide while 229 constituted mature peptide. The deduced amino acid sequences resembled those of class II molecules of other species for all the conserved residues having critical functional role. But a single N-linked glycosylation site in á1 was observed in cattle and buffalo when compared to human and swine which contain a second site in á2 domain. The signal peptide was found more variable among the species compared. Comparison of nucleotide and amino acid sequences among related species and dendrogram constructed revealed that the cattle sequences are more similar to buffalo sequences.

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