scholarly journals Rat liver β-glucuronidase. cDNA cloning, sequence comparisons and expression of a chimeric protein in COS cells

1988 ◽  
Vol 250 (2) ◽  
pp. 547-555 ◽  
Author(s):  
P P Powell ◽  
J W Kyle ◽  
R D Miller ◽  
J Pantano ◽  
J H Grubb ◽  
...  
Keyword(s):  
Amino Acid ◽  
Liver Enzyme ◽  
Rat Liver ◽  
Signal Sequence ◽  
Proteolytic Processing ◽  
Amino Acid Difference ◽  
Amino Acid Residues ◽  
Sequence Comparisons ◽  
Chimeric Clone ◽  
Cos Cells

A cDNA for rat liver beta-glucuronidase was isolated, its sequence determined and its expression after transfection into COS cells studied. The deduced amino acid sequence of the rat liver clone showed 77% homology with that from the cDNA for human placental beta-glucuronidase and 47% homology with that deduced from the cDNA for Escherichia coli beta-glucuronidase. Several differences were found between the cDNA from rat liver and that previously reported from rat preputial gland. Only one change leads to an amino acid difference in the mature enzyme. A chimeric clone was constructed by using a fragment encoding the first 18 amino acid residues of the signal sequence from the human placental cDNA clone and a fragment from the rat clone encoding four amino acid residues of the signal sequence, all 626 amino acid residues of the mature rat enzyme, and all of the 3′ untranslated region. After transfection into COS cells the chimeric clone expressed beta-glucuronidase activity that was specifically immunoprecipitated by antibody to rat beta-glucuronidase. The Mr value of 76,000 of the expressed gene product was characteristic of the glycosylated rat enzyme. It was proteolytically processed in COS cells to Mr 75,000 6 h after metabolic labelling. At least 50% of the expressed enzyme was secreted at 60 h post-transfection, but the secreted enzyme did not undergo proteolytic processing. These results provide evidence that the partial cDNA isolated from a rat liver library contains the complete coding sequence for the mature rat liver enzyme and that the chimeric signal sequence allows normal biosynthesis and processing of the transfected rat liver enzyme in COS cells.

scholarly journals Characterization of the Sequence Specificity Determinants Required for Processing and Control of Sex Pheromone by the Intramembrane Protease Eep and the Plasmid-Encoded Protein PrgY

2007 ◽  
Vol 190 (4) ◽  
pp. 1172-1183 ◽  
Author(s):  
Josephine R. Chandler ◽  
Gary M. Dunny
Keyword(s):  
Amino Acid ◽  
Signal Sequence ◽  
Constitutive Expression ◽  
Direct Interaction ◽  
Proteolytic Processing ◽  
Sequence Specificity ◽  
Amino Acid Residues ◽  
And Control ◽  
Specificity Determinants

ABSTRACT Conjugative transfer of the Enterococcus faecalis plasmid pCF10 is induced by the peptide pheromone cCF10 when recipient-produced cCF10 is detected by donors. cCF10 is produced by proteolytic processing of the signal sequence of a chromosomally encoded lipoprotein (CcfA). In donors, endogenously produced cCF10 is carefully controlled to prevent constitutive expression of conjugation functions, an energetically wasteful process, except in vivo, where endogenous cCF10 induces a conjugation-linked virulence factor. Endogenous cCF10 is controlled by two plasmid-encoded products; a membrane protein PrgY reduces pheromone levels in donors, and a secreted inhibitor peptide iCF10 inhibits the residual endogenous pheromone that escapes PrgY control. In this study we genetically determined the amino acid specificity determinants within PrgY, cCF10, and the cCF10 precursor that are necessary for cCF10 processing and for PrgY-mediated control. We showed that amino acid residues 125 to 241 of PrgY are required for specific recognition of cCF10 and that PrgY recognizes determinants within the heptapeptide cCF10 sequence, supporting a direct interaction between PrgY and mature cCF10. In addition, we found that a regulated intramembrane proteolysis (RIP) family pheromone precursor-processing protein Eep recognizes amino acids N-terminal to cCF10 in the signal sequence of CcfA. These results support a model where Eep directly targets pheromone precursors for RIP and PrgY interacts directly with the mature cCF10 peptide during processing. Despite evidence that both PrgY and Eep associate with cCF10 in or near the membrane, results presented here indicate that these two proteins function independently.

scholarly journals Cloning and sequencing of rat liver carboxylesterase ES-4 (microsomal palmitoyl-CoA hydrolase)

1996 ◽  
Vol 313 (3) ◽  
pp. 821-826 ◽  
Author(s):  
Mariette ROBBI ◽  
Emile VAN SCHAFTINGEN ◽  
Henri BEAUFAY
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Signal Peptide ◽  
Catalytic Properties ◽  
Amino Acid Residues ◽  
Cloning And Sequencing ◽  
Cos Cells ◽  
Coa Hydrolase ◽  
Naphthyl Acetate ◽  
Retention Signal

A cDNA which encodes a carboxylesterase of 561 amino acid residues including a cleavable signal peptide is described. The enzyme expressed in COS cells migrates during PAGE (SDS-, and non-denaturing) as a single prominent band in the region of liver ES-4. It ends in the C-terminal cell-retention signal -HNEL, which, in COS cells overexpressing the enzyme, appears to be slightly less efficient than the signals -HTEL and -HVEL of ES-3 and ES-10 respectively. Glycosylation is not essential for intracellular retention, but leads to a higher activity. As do many carboxylesterases, the enzyme expressed in COS cells hydrolyses o-nitrophenyl acetate and α-naphthyl acetate. It also hydrolyses acetanilide, although less efficiently than ES-3, and, distinctively, palmitoyl-CoA. In addition to the four canonical Cys residues of the carboxylesterases, it contains a fifth, unpaired Cys336, which apparently is not essential for the catalytic properties. Indeed, treatment with iodoacetamide or substitution of Cys336 by Phe does not markedly alter the activity of the enzyme on the various substrates. The predicted structure of ES-4 is highly homologous to that of two other recently cloned esterases which also end in -HNEL [Yan, Yang, Brady and Parkinson (1994) J. Biol. Chem. 269, 29688–29696; Yan, Yang and Parkinson (1995) Arch. Biochem. Biophys. 317, 222–234]. Together, these isoenzymes probably account for the closely spaced bands observed in the region of ES-4 in non-denaturing PAGE.

scholarly journals Molecular characterization of the BRO beta-lactamase of Moraxella (Branhamella) catarrhalis.

1996 ◽  
Vol 40 (4) ◽  
pp. 966-972 ◽  
Author(s):  
H J Bootsma ◽  
H van Dijk ◽  
J Verhoef ◽  
A Fleer ◽  
F R Mooi
Keyword(s):  
Amino Acid ◽  
Active Sites ◽  
Signal Sequence ◽  
Amino Acid Difference ◽  
Beta Lactamase ◽  
Amino Acid Residues ◽  
Beta Lactam ◽  
Insertional Inactivation ◽  
Membrane Compartment ◽  
Branhamella Catarrhalis

A rapid increase in the prevalence of beta-lactamase-producing Moraxella (Branhamella) catarrhalis strains has been noticed during the last decades. Today, more than 80% of strains isolated worldwide produce beta-lactamase. To investigate beta-lactamase(s) of M. catarrhalis at the molecular level, the BRO-1 beta-lactamase gene (bla) was isolated as part of a 4,223-bp HindIII fragment. Sequence analysis indicated that bla encodes a polypeptide of 314 amino acid residues. Insertional inactivation of bla in M. catarrhalis resulted in complete abrogation of beta-lactamase production and ampicillin resistance, demonstrating that bla is solely responsible for beta-lactam resistance. Comparison with other beta-lactamases suggested that M. catarrhalis beta-lactamase is a unique enzyme with conserved residues at the active sites. The presence of a signal sequence for lipoproteins suggested that it is lipid modified at its N terminus. In keeping with this assumption was the observation that 10% of beta-lactamase activity was found in the membrane compartment of M. catarrhalis. M. catarrhalis strains produce two types of beta-lactamase, BRO-1 and BRO-2, which differ in their isoelectric points. The BRO-1 and BRO-2 genes from two ATCC strains of M. catarrhalis were sequenced, and only one amino acid difference was found between the predicted products. However, there was a 21-bp deletion in the promoter region of the BRO-2 gene, possibly explaining the lower level of production of BRO-2. The G + C content of bla (31%) was significantly lower than those of the flanking genes (47 and 50%), and the overall G + C content of the M. catarrhalis genome (41%). These results indicate that bla was acquired by horizontal gene transfer from another, still unknown species.

Peroxisome targeting signal of rat liver acyl-coenzyme A oxidase resides at the carboxy terminus

1989 ◽  
Vol 9 (1) ◽  
pp. 83-91
Author(s):  
S Miyazawa ◽  
T Osumi ◽  
T Hashimoto ◽  
K Ohno ◽  
S Miura ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Coenzyme A ◽  
Terminal Region ◽  
Proteinase K ◽  
Amino Acid Residues ◽  
C Terminus ◽  
Targeting Signal ◽  
Acyl Coenzyme A

To identify the topogenic signal of peroxisomal acyl-coenzyme A oxidase (AOX) of rat liver, we carried out in vitro import experiments with mutant polypeptides of the enzyme. Full-length AOX and polypeptides that were truncated at the N-terminal region were efficiently imported into peroxisomes, as determined by resistance to externally added proteinase K. Polypeptides carrying internal deletions in the C-terminal region exhibited much lower import activities. Polypeptides that were truncated or mutated at the extreme C terminus were totally import negative. When the five amino acid residues at the extreme C terminus were attached to some of the import-negative polypeptides, the import activities were rescued. Moreover, the C-terminal 199 and 70 amino acid residues of AOX directed fusion proteins with two bacterial enzymes to peroxisomes. These results are interpreted to mean that the peroxisome targeting signal of AOX residues at the C terminus and the five or fewer residues at the extreme terminus have an obligatory function in targeting. The C-terminal internal region also has an important role for efficient import, possibly through a conformational effect.

scholarly journals STUDY ON THE SITE OF BIOSYNTHESIS OF β-GLUCURONIDASE AND ITS APPEARANCE IN LYSOSOME IN NORMAL AND HYPOXIC RATS

1970 ◽  
Vol 18 (8) ◽  
pp. 529-541 ◽  
Author(s):  
JULIEN L. VAN LANCKER ◽  
PATRICK L. LENTZ
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Liver Enzyme ◽  
Rat Liver ◽  
Microsomal Enzymes ◽  
Enzyme Preparations ◽  
Lysosomal Fraction ◽  
Regenerating Rat Liver ◽  
Cell Fractions

For the purpose of investigating the site of synthesis of β-glucuronidase, the enzyme was purified, after injection of labeled amino acids, from various cell fractions of regenerating rat liver. Enzyme preparations purified from microsomal, lysosomal, mitochondrial, nuclear and supernatant fractions had identical catalytic and electrophoretic properties. In nonhypoxic rats, incorporation was detectable only in the microsomal enzymes and maximum labeling occurred 30 min after the injection of the labeled amino acid. No label was detectable in the enzyme purified from the lysosomal fraction of nonhypoxic animals. Labeling of enzyme purified from lysosomal fraction was, however, significant after 2 hr of hypoxia.

Mitochondrial translocation and processing of the precursor to the α-subunit of rat liver succinyl-CoA synthetase

1990 ◽  
Vol 68 (1) ◽  
pp. 292-299 ◽  
Author(s):  
Ramanath Majumdar ◽  
William A. Bridger
Keyword(s):  
Rat Liver ◽  
Signal Sequence ◽  
Proteolytic Processing ◽  
In Vitro Translation ◽  
Rat Liver Mitochondria ◽  
Translation System ◽  
Cdna Insert ◽  
Α Subunit ◽  
Mitochondrial Translocation ◽  
Succinyl Coa Synthetase

Succinyl-CoA synthetase functions in the mitochondrial matrix as an αβ-dimer. Its constitutive subunits are thus expected to be encoded in the nucleus and synthesized in the cytoplasm as precursors containing signal sequences for mitochondrial translocation. We have previously reported the isolation and sequence of a rat liver cDNA clone (λSCS19) that apparently encodes the cytoplasmic precursor to the α-subunit. Here we report the preparation of mRNA transcripts of this cDNA insert and their in vitro translation to produce labeled protein that can be translocated across the membranes of subsequently added rat liver mitochondria. Translocation is accompanied by proteolytic processing to convert the 34.5-kilodalton precursor to the 32-kilodalton mature form of the subunit. The N-terminal sequence of the mature α-subunit from the GTP-specific isozyme has been determined by sequential Edman degradation and compared with the amino acid sequence deduced from the cDNA. This confirms that the cloned sequence encodes the GTP-specific α-subunit, and establishes that the point of cleavage is between histidyl and glycyl residues and that the signal sequence consists of 27 residues. The signal sequence shares characteristics of other mitochondrial targeting sequences that have been elucidated (largely of yeast mitochondrial precursors), including the potential to form an amphiphilic helix. Import is dependent upon the presence of ATP and is inhibited by compounds that diminish mitochondrial membrane potential. Translocation of the precursor is effective for precursor produced by the reticulocyte translation system, but is not seen for the product that is translated by a wheat germ extract, indicating that the latter may lack a factor or component that is necessary for the targeting and import process.Key words: succinyl-CoA synthetase, mitochondria, protein translocation, signal sequence.

Mutations in the signal sequence of prepro-alpha-factor inhibit both translocation into the endoplasmic reticulum and processing by signal peptidase in yeast cells

1989 ◽  
Vol 9 (11) ◽  
pp. 4977-4985
Author(s):  
D S Allison ◽  
E T Young
Keyword(s):  
Endoplasmic Reticulum ◽  
Amino Acid ◽  
Signal Peptide ◽  
Signal Sequence ◽  
Proteolytic Processing ◽  
Yeast Cells ◽  
Signal Peptidase ◽  
Single Amino Acid ◽  
Alpha Factor

The effects of five single-amino-acid substitution mutations within the signal sequence of yeast prepro-alpha-factor were tested in yeast cells. After short pulse-labelings, virtually all of the alpha-factor precursor proteins from a wild-type gene were glycosylated and processed by signal peptidase. In contrast, the signal sequence mutations resulted in the accumulation of mostly unglycosylated prepro-alpha-factor after a short labeling interval, indicating a defect in translocation of the protein into the endoplasmic reticulum. Confirming this interpretation, unglycosylated mutant prepro-alpha-factor in cell extracts was sensitive to proteinase K and therefore in a cytosolic location. The signal sequence mutations reduced the rate of translocation into the endoplasmic reticulum by as much as 25-fold or more. In at least one case, mutant prepro-alpha-factor molecules were translocated almost entirely posttranslationally. Four of the five mutations also reduced the rate of proteolytic processing by signal peptidase in vivo, even though the signal peptide alterations are not located near the cleavage site. This study demonstrates that a single-amino-acid substitution mutation within a eucaryotic signal peptide can affect both translocation and proteolytic processing in vivo and may indicate that the recognition sequences for translocation and processing overlap within the signal peptide.

scholarly journals A Two-Amino Acid Difference in the Coat Protein of Satellite panicum mosaic virus Isolates Is Responsible for Differential Synergistic Interactions with Panicum mosaic virus

2019 ◽  
Vol 32 (4) ◽  
pp. 479-490 ◽  
Author(s):  
R. V. Chowda-Reddy ◽  
Nathan Palmer ◽  
Serge Edme ◽  
Gautam Sarath ◽  
Frank Kovacs ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Coat Protein ◽  
Mosaic Virus ◽  
Severe Disease ◽  
Amino Acid Difference ◽  
Amino Acid Residues ◽  
Genomic Rna ◽  
Proso Millet ◽  
Synergistic Interactions

Panicum mosaic virus (PMV) (genus Panicovirus, family Tombusviridae) and its molecular parasite, Satellite panicum mosaic virus (SPMV), synergistically interact in coinfected proso and pearl millet (Panicum miliaceum L.) plants resulting in a severe symptom phenotype. In this study, we examined synergistic interactions between the isolates of PMV and SPMV by using PMV-NE, PMV85, SPMV-KS, and SPMV-Type as interacting partner viruses in different combinations. Coinfection of proso millet plants by PMV-NE and SPMV-KS elicited severe mosaic, chlorosis, stunting, and eventual plant death compared with moderate mosaic, chlorotic streaks, and stunting by PMV85 and SPMV-Type. In reciprocal combinations, coinfection of proso millet by either isolate of PMV with SPMV-KS but not with SPMV-Type elicited severe disease synergism, suggesting that SPMV-KS was the main contributor for efficient synergistic interaction with PMV isolates. Coinfection of proso millet plants by either isolate of PMV and SPMV-KS or SPMV-Type caused increased accumulation of coat protein (CP) and genomic RNA copies of PMV, compared with infections by individual PMV isolates. Additionally, CP and genomic RNA copies of SPMV-KS accumulated at substantially higher levels, compared with SMPV-Type in coinfected proso millet plants with either isolate of PMV. Hybrid viruses between SPMV-KS and SPMV-Type revealed that SPMV isolates harboring a CP fragment with four differing amino acids at positions 18, 35, 59, and 98 were responsible for differential synergistic interactions with PMV in proso millet plants. Mutation of amino acid residues at these positions in different combinations in SPMV-KS, similar to those as in SPMV-Type or vice-versa, revealed that A35 and R98 in SPMV-KS CP play critical roles in enhanced synergistic interactions with PMV isolates. Taken together, these data suggest that the two distinct amino acids at positions 35 and 98 in the CP of SPMV-KS and SPMV-Type are involved in the differential synergistic interactions with the helper viruses.

scholarly journals Highly Conserved Configuration of Catalytic Amino Acid Residues among Calicivirus-Encoded Proteases

2007 ◽  
Vol 81 (13) ◽  
pp. 6798-6806 ◽  
Author(s):  
Tomoichiro Oka ◽  
Mami Yamamoto ◽  
Masaru Yokoyama ◽  
Satoko Ogawa ◽  
Grant S. Hansman ◽  
...  
Keyword(s):  
Amino Acid ◽  
Proteolytic Processing ◽  
Site Directed Mutagenesis ◽  
Computer Assisted ◽  
Amino Acid Residues ◽  
Reading Frame ◽  
Binding Cleft ◽  
Viral Polyprotein ◽  
Mutant Forms

ABSTRACT A common feature of caliciviruses is the proteolytic processing of the viral polyprotein catalyzed by the viral 3C-like protease encoded in open reading frame 1 (ORF1). Here we report the identification and structural characterization of the protease domains and amino acid residues in sapovirus (SaV) and feline calicivirus (FCV). The in vitro expression and processing of a panel of truncated ORF1 polyproteins and corresponding mutant forms showed that the functional protease domain is 146 amino acids (aa) in SaV and 154 aa in FCV. Site-directed mutagenesis of the protease domains identified four amino acid residues essential to protease activities: H31, E52, C116, and H131 in SaV and H39, E60, C122, and H137 in FCV. A computer-assisted structural analysis showed that despite high levels of diversity in the primary structures of the protease domains in the family Caliciviridae, the configurations of the H, E, C, and H residues are highly conserved, with these residues positioned closely along the inner surface of the potential binding cleft for the substrate. These results strongly suggest that the H, E, C, and H residues are involved in the formation of a conserved catalytic surface of the SaV and FCV 3C-like proteases.

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