scholarly journals Variant Amino Acid Residues Alter the Enzyme Activity of Peanut Type 2 Diacylglycerol Acyltransferases

2017 ◽  
Vol 8 ◽  
Author(s):  
Ling Zheng ◽  
Jay Shockey ◽  
Fei Bian ◽  
Gao Chen ◽  
Lei Shan ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Amino Acid Residues ◽  
Variant Amino Acid

scholarly journals Identification of a Gene Involved in Assembly ofActinomyces naeslundii T14V Type 2 Fimbriae

1998 ◽  
Vol 66 (4) ◽  
pp. 1482-1491 ◽  
Author(s):  
Maria K. Yeung ◽  
Jacob A. Donkersloot ◽  
John O. Cisar ◽  
Pamela A. Ragsdale
Keyword(s):  
Amino Acid ◽  
Kanamycin Resistance ◽  
Amino Acid Residues ◽  
Subunit Protein ◽  
Actinomyces Naeslundii ◽  
Cell Extracts ◽  
Acid Protein ◽  
Structural Subunit ◽  
Antipeptide Antibody

ABSTRACT The nucleotide sequence of the Actinomyces naeslundiiT14V type 2 fimbrial structural subunit gene, fimA, and the 3′ flanking DNA region was determined. The fimA gene encoded a 535-amino-acid precursor subunit protein (FimA) which included both N-terminal leader and C-terminal cell wall sorting sequences. A second gene, designated orf365, that encoded a 365-amino-acid protein which contained a putative transmembrane segment was identified immediately 3′ to fimA. Mutants in which either fimA or orf365 was replaced with a kanamycin resistance gene did not participate in type 2 fimbriae-mediated coaggregation with Streptococcus oralis34. Type 2 fimbrial antigen was not detected in cell extracts of thefimA mutant by Western blotting with anti-A. naeslundii type 2 fimbrial antibody, but the subunit protein was detected in extracts of the orf365 mutant. The subunit protein detected in this mutant also was immunostained by an antibody raised against a synthetic peptide representing the C-terminal 20 amino acid residues of the predicted FimA. The antipeptide antibody reacted with FimA isolated from the recombinant Escherichia coliclone containing fimA but did not react with purified type 2 fimbriae in extracts of the wild-type strain. These results indicate that synthesis of type 2 fimbriae in A. naeslundii T14V may involve posttranslational cleavage of both the N-terminal and C-terminal peptides of the precursor subunit and also the expression oforf365.

scholarly journals Structure–function studies of human deoxyhypusine synthase: identification of amino acid residues critical for the binding of spermidine and NAD

2001 ◽  
Vol 355 (3) ◽  
pp. 841-849 ◽  
Author(s):  
Chang Hoon LEE ◽  
Patrick Y. UM ◽  
Myung Hee PARK
Keyword(s):  
Crystal Structure ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Binding Sites ◽  
Binding Pocket ◽  
Complete Loss ◽  
Amino Acid Residues ◽  
Deoxyhypusine Synthase ◽  
Positive Identification ◽  
Insight Into

Deoxyhypusine synthase catalyses the first step in the biosynthesis of hypusine [Nε-(4-amino-2-hydroxybutyl)lysine]. The crystal structure of human deoxyhypusine synthase in complex with NAD revealed four NAD-binding sites per enzyme tetramer, and led to a prediction of the spermidine-binding pocket. We have replaced each of the seven amino acid residues at the predicted spermidine-binding site, and eleven residues that contact NAD, on an individual basis with alanine. Of the amino acid residues at the spermidine site, substitution of Asp-243, Trp-327, His-288, Asp-316 or Glu-323 with alanine caused an almost complete loss of spermidine binding and enzyme activity; only the mutation Tyr-305 → Ala showed partial binding and activity. His-288 → Ala was also deficient in terms of binding NAD. NAD binding was significantly reduced in all of the NAD-site mutant enzymes, except for Glu-137 → Ala, which showed a normal binding of NAD, but was totally lacking in spermidine binding. Of the NAD-site mutant enzymes, Asp-342 → Ala, Asp-313 → Ala and Asp-238 → Ala displayed the lowest binding of NAD. These enzymes and His-288Ala also showed a reduced binding of spermidine, presumably because spermidine binding is dependent on NAD. These findings permit the positive identification of amino acid residues critical for binding of spermidine and NAD, and provide a new insight into the complex molecular interactions involved in the deoxyhypusine synthase reaction.

scholarly journals Novel LinA Type 3 δ-Hexachlorocyclohexane Dehydrochlorinase

2015 ◽  
Vol 81 (21) ◽  
pp. 7553-7559 ◽  
Author(s):  
Nidhi Shrivastava ◽  
Zbynek Prokop ◽  
Ashwani Kumar
Keyword(s):  
Amino Acid ◽  
Primary Structure ◽  
Degradation Pathway ◽  
Amino Acid Residues ◽  
Hch Isomers ◽  
New Variant ◽  
Type 3

ABSTRACTLinA is the first enzyme of the microbial degradation pathway of a chlorinated insecticide, hexachlorocyclohexane (HCH), and mediates the dehydrochlorination of α-, γ-, and δ-HCH. Its two variants, LinA type 1 and LinA type 2, which differ at 10 out of 156 amino acid residues, have been described. Their activities for the metabolism of different HCH isomers differ considerably but overall are high for γ-HCH, moderate for α-HCH, low for δ-HCH, and lacking for β-HCH. Here, we describe the characterization of a new variant of this enzyme, LinA type 3, whose gene was identified from the metagenome of an HCH-contaminated soil sample. Its deduced primary structure in the region spanning amino acid residues 1 to 147 of the protein exhibits 17 and 12 differences from LinA type 1 and LinA type 2, respectively. In addition, the residues GIHFAPS, present at the region spanning residues 148 to 154 in both LinA type 1 and LinA type 2, are deleted in LinA type 3.The activity of LinA type 3 for the metabolism of δ-HCH is several orders of magnitude higher than that of LinA type 1 or LinA type 2 and can be useful for improvement of the metabolism of δ-HCH.

Activity of vertebrate gonadotropin-releasing hormones and analogs with variant amino acid residues in positions 5, 7 and 8 in the goldfish pituitary

1992 ◽  
Vol 37 (3) ◽  
pp. 271-284 ◽  
Author(s):  
Hamid R. Habibi ◽  
Richard E. Peter ◽  
Carol S. Nahorniak ◽  
Raymond C. de L. Milton ◽  
Robert P. Millar
Keyword(s):  
Amino Acid ◽  
Amino Acid Residues ◽  
Variant Amino Acid

scholarly journals Biosynthesis in vitro of tryptophanase by polyribosomes from induced cultures of Escherichia coli

1971 ◽  
Vol 123 (3) ◽  
pp. 355-365 ◽  
Author(s):  
S. A. M. Khairul Bashar ◽  
J. H. Parish ◽  
Marjorie Brown
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Enzyme Synthesis ◽  
Supernatant Fraction ◽  
Amino Acid Residues ◽  
Radioactive Amino Acid ◽  
Tryptophanase Activity

1. Polyribosomes were isolated from Escherichia coli grown in media in which tryptophanase is induced and in which it is repressed. The polyribosomes from the induced bacteria had a small amount of tryptophanase activity associated with them. 2. A portion of the enzyme activity remained bound to polyribosomes during centrifuging in sucrose gradients. 3. Incubation of tryptophanase-containing polyribosomes with puromycin released enzyme activity. 4. The binding of the enzyme to the polyribosomes did not depend on the presence of DNA. 5. When the polyribosomes were incubated under conditions of protein synthesis with supernatant fraction obtained from repressed bacteria, a small but statistically significant increase in enzyme activity was produced. 6. When a radioactive amino acid was included in the incubation mixture for the tryptophanase system a radioactive protein was obtained whose chromatographic, electrophoretic and sedimentation properties were identical with those of tryptophanase. 7. The amount of incorporation was consistent with the amount of new enzyme synthesis predicted by the increase in enzyme activity. Both radioactive incorporation and increase in enzyme activity were shown to be energy-dependent and also negative controls were obtained by using zero-time incubations or polyribosomes isolated from either repressed cells or a mutant lacking the ability to produce tryptophanase. 8. The distribution of radioactive leucine in the carboxyl region of the newly labelled tryptophanase was examined by digesting the labelled protein with carboxypeptidases. It was shown that the radioactivity was more highly concentrated towards the carboxyl terminus when the incubation times for protein synthesis were shorter (implying that, with longer incubation times, longer lengths of polypeptide chain contained radioactive amino acid residues).

scholarly journals Phylogenetic Characteristics of Canine Parvovirus Type 2c Variant Endemic in Shanghai, China

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2257
Author(s):  
Chengqian Liu ◽  
Jun Gao ◽  
Hong Li ◽  
Fengping Sun ◽  
Hongyu Liang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Divergence Time ◽  
Canine Parvovirus ◽  
Amino Acid Sequences ◽  
Amino Acid Residues ◽  
Positive Rate ◽  
Shanghai City ◽  
Pcr Method ◽  
Full Length Genome

Canine parvovirus type 2 (CPV-2) has spread and mutated globally over the past 40 years. In the present study, 206 samples from dogs suspected of CPV-2 infection were collected from five veterinary clinics in Shanghai city, China. The average positive rate for CPV-2 was detected to be 40.78% using the PCR method. Using an F81 cell (feline kidney cell) culture, the isolates of three CPV-2c strains were obtained. The near full-length genome sequences of the isolates were determined and submitted to GenBank: CPV-SH2001 (MW650830), CPV-SH2002 (MW811188), and CPV-SH2003 (MW811189). By comparing the amino acid sequences of 12 CPV strains with those of 48 related strains retrieved from GenBank, all of the CPV strains from Shanghai were typed as belonging to a relatively new CPV-2c variant spreading in Asia, with typical amino acid residues (5Gly, 267Tyr, 324Ile, and 370Arg) in the VP2 protein. The divergence time of this new CPV-2c clade was estimated by the phylogenetic tree using the maximum likelihood and RelTime with Dated Tips (RTDT) approaches. Our results indicate that the 426 and 324 VP2 amino acid residues are under strong selection pressure with a posterior probability of 0.966 and 0.943, respectively. Therefore, this study provides insight into the phylogenetic characteristics of the current CPV-2c variant in Shanghai city, China.

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