Recruited lysosomal enzymes as major digestive enzymes in insects

2019 ◽  
Vol 47 (2) ◽  
pp. 615-623 ◽  
Author(s):  
Walter R. Terra ◽  
Renata O. Dias ◽  
Clélia Ferreira
Keyword(s):  
Digestive Enzymes ◽  
Lysosomal Enzymes ◽  
Proteolytic Enzymes ◽  
Seed Proteins ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Selective Pressures ◽  
Mass Recruitment ◽  
Critical Regions ◽  
Protein Diets

Abstract The mass recruitment to the midgut contents of lysosomal proteolytic enzymes occurred in insects under three major selective pressures. Hemipteran (true bugs, aphids, and cicadas) ancestors lost their serine peptidases (SP) on adapting to feed on protein-free plant sap. When they returned to protein diets, their cathepsins L and B were recruited to replace their lost SP. Among beetles of the series Cucujiformia, cathepsins L were recruited to hydrolyze ingested plant inhibitors that affect their major SP and/or to deal with special seed proteins, such as prolamins. Larval flies have a very acid middle midgut and use cathepsin D to digest bacteria from their infected food. All the recruited enzymes originated from duplicated genes. The recruited digestive enzymes differ from their lysosomal counterparts in critical regions of their amino acid sequences that resulted in changes in substrate specificities and other kinetic properties. The discharge of digestive cathepsins in the midgut contents, instead of lysosomes, seems to be a consequence of their overexpression or the existence of new targeting signals. Their activation at the midgut contents occurs by an autoactivation mechanism or with the help of other enzymes or by a combination of both. The targeting to lysosomes of the insect lysosomal enzymes does not follow the mammalian mannose 6-phosphate route, but an incompletely known mechanism.

scholarly journals Ancestral sequence reconstruction produces thermally stable enzymes with mesophilic enzyme-like catalytic properties

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ryutaro Furukawa ◽  
Wakako Toma ◽  
Koji Yamazaki ◽  
Satoshi Akanuma
Keyword(s):  
Low Temperature ◽  
Catalytic Properties ◽  
Amino Acid Sequences ◽  
Ancestral Sequence ◽  
Kinetic Properties ◽  
Reconstruction Technique ◽  
Thermally Stable ◽  
Ancestral Sequence Reconstruction ◽  
Ancestral Sequences ◽  
Sequence Reconstruction

Abstract Enzymes have high catalytic efficiency and low environmental impact, and are therefore potentially useful tools for various industrial processes. Crucially, however, natural enzymes do not always have the properties required for specific processes. It may be necessary, therefore, to design, engineer, and evolve enzymes with properties that are not found in natural enzymes. In particular, the creation of enzymes that are thermally stable and catalytically active at low temperature is desirable for processes involving both high and low temperatures. In the current study, we designed two ancestral sequences of 3-isopropylmalate dehydrogenase by an ancestral sequence reconstruction technique based on a phylogenetic analysis of extant homologous amino acid sequences. Genes encoding the designed sequences were artificially synthesized and expressed in Escherichia coli. The reconstructed enzymes were found to be slightly more thermally stable than the extant thermophilic homologue from Thermus thermophilus. Moreover, they had considerably higher low-temperature catalytic activity as compared with the T. thermophilus enzyme. Detailed analyses of their temperature-dependent specific activities and kinetic properties showed that the reconstructed enzymes have catalytic properties similar to those of mesophilic homologues. Collectively, our study demonstrates that ancestral sequence reconstruction can produce a thermally stable enzyme with catalytic properties adapted to low-temperature reactions.

scholarly journals Properties of N-acetylglucosamine 1-phosphotransferase from human lymphoblasts

1987 ◽  
Vol 248 (1) ◽  
pp. 151-159 ◽  
Author(s):  
L Little ◽  
M Alcouloumre ◽  
A M Drotar ◽  
S Herman ◽  
R Robertson ◽  
...  
Keyword(s):  
Cell Lines ◽  
Lysosomal Enzymes ◽  
Ricinus Communis ◽  
Fibroblast Cell ◽  
Kinetic Properties ◽  
Cell Enzyme ◽  
Unique System ◽  
Normal Individuals ◽  
Human Lymphoblast ◽  
Fibroblast Cell Lines

Human lymphoblast and fibroblast cell lines from a patient with I-cell disease and normal individuals were characterized with respect to certain properties of UDP-N-acetylglucosamine:lysosomal enzyme precursor N-acetylglucosamine phosphotransferase. The enzyme isolated from normal lymphoblast and fibroblast cell lines expressed similar kinetic properties, substrate specificities and subcellular localizations. Coincident with the severe reduction of N-acetylglucosamine phosphotransferase activity in both I-cell fibroblast and lymphoblast cell lines, there was an increased secretion of several lysosomal enzymes compared to normal controls. Subsequent examination of N-acetyl-beta-D-hexosaminidase secreted by the I-cell lymphoblasts demonstrated a significant increase in adsorption of the I-cell enzyme to Ricinus communis agglutinin, a galactose-specific lectin. However, the I-cell lymphoblasts did not exhibit the significant decrease in intracellular lysosomal activities seen in I-cell fibroblasts. Our results suggest that lymphoblasts not only represent an excellent source for the purification of N-acetylglucosamine phosphotransferase, but in addition, represent a unique system for studying alternate mechanisms involved in the targeting of lysosomal enzymes.

scholarly journals Insights into the Selective Pressures Restricting Pelargonium Flower Break Virus Genome Variability: Evidence for Host Adaptation

2006 ◽  
Vol 80 (16) ◽  
pp. 8124-8132 ◽  
Author(s):  
Patricia Rico ◽  
Pilar Ivars ◽  
Santiago F. Elena ◽  
Carmen Hernández
Keyword(s):  
Amino Acid ◽  
Leucine Zipper ◽  
Critical Role ◽  
Chenopodium Quinoa ◽  
Virus Genome ◽  
Acid Sites ◽  
Genomic Region ◽  
Amino Acid Sequences ◽  
Nucleotide Substitutions ◽  
Selective Pressures

ABSTRACT The molecular diversity of Pelargonium flower break virus (PFBV) was assessed using a collection of isolates from different geographical origins, hosts, and collecting times. The genomic region examined was 1,828 nucleotides (nt) long and comprised the coding sequences for the movement (p7 and p12) and the coat (CP) proteins, as well as flanking segments including the entire 3′ untranslated region (3′ UTR). Some constraints limiting viral heterogeneity could be inferred from sequence analyses, such as the conservation of the amino acid sequences of p7 and of the shell domain of the CP, the maintenance of a leucine zipper motif in p12, and the preservation of a particular folding in the 3′ UTR. A remarkable covariation, involving five specific amino acid sites, was found in the CP of isolates largely propagated in the local lesion host Chenopodium quinoa and in the progeny of a PFBV variant subjected to serial passages in this host. Concomitant with this covariation, up to 30 nucleotide substitutions in a 1,428-nt region of the viral RNA could be attributable to C. quinoa-specific adaptation, representing one of the most outstanding cases of host-driven genome variation for a plant virus. Globally, the results indicate that the selective pressures exerted by the host play a critical role in shaping PFBV populations and that these populations are likely being selected for at both protein and RNA levels.

Comparison of the structural and kinetic properties of the cytochrome c nitrite reductases from Escherichia coli, Wolinella succinogenes, Sulfurospirillum deleyianum and Desulfovibrio desulfuricans

2006 ◽  
Vol 34 (1) ◽  
pp. 143-145 ◽  
Author(s):  
T.A. Clarke ◽  
A.M. Hemmings ◽  
B. Burlat ◽  
J.N. Butt ◽  
J.A. Cole ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Active Site ◽  
Desulfovibrio Desulfuricans ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Wolinella Succinogenes ◽  
Nitrite Reductases ◽  
Sulphite Reductase

The recent crystallographic characterization of NrfAs from Sulfurospirillum deleyianum, Wolinella succinogenes, Escherichia coli and Desulfovibrio desulfuricans allows structurally conserved regions to be identified. Comparison of nitrite and sulphite reductase activities from different bacteria shows that the relative activities vary according to organism. By comparison of both amino acid sequences and structures, differences can be identified in the monomer–monomer interface and the active-site channel; these differences could be responsible for the observed variance in substrate activity and indicate that subtle changes in the NrfA structure may optimize the enzyme for different roles.

scholarly journals LYSOSOMAL ENZYMES OF RAT INTESTINAL MUCOSA

1964 ◽  
Vol 23 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Lichu Hsu ◽  
A. L. Tappel
Keyword(s):  
Rat Liver ◽  
Intestinal Mucosa ◽  
Digestive Enzymes ◽  
Lysosomal Enzymes ◽  
Liver Enzymes ◽  
Enzyme Release ◽  
Centrifugal Forces ◽  
Physiological Functions ◽  
Specific Activities

Six intracellular hydrolases known to be associated with lysosomes in rat liver were found in rat intestinal mucosa. The extent to which they were particulate-bound and the degree of enzyme release when the particulate fractions were suspended in hypotonic media followed the same pattern in both mucosa and liver. The specific activities of the mucosa enzymes were either comparable to or slightly smaller than those of the liver enzymes. These results suggest that the mucosa hydrolases belong to lysosome-like particles. However, differential fractionation of the mucosa indicated that the particles from the mucosa sediment at lower centrifugal forces than do those from the liver and are more heterogeneous in size, bearing a closer resemblance to kidney lysosomes. Possible physiological functions of particulate-bound digestive enzymes in intestinal mucosa are discussed.

scholarly journals The “Green” Form I Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from the Nonsulfur Purple BacteriumRhodobacter capsulatus

1999 ◽  
Vol 181 (13) ◽  
pp. 3935-3941 ◽  
Author(s):  
Kempton M. Horken ◽  
F. Robert Tabita
Keyword(s):  
Genetic Manipulation ◽  
Sequence Similarity ◽  
Large Subunit ◽  
Small Subunit ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Phylogenetic Groups ◽  
Bisphosphate Carboxylase ◽  
Related Organism ◽  
Green Form

ABSTRACT Form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) of the Calvin-Benson-Bassham cycle may be divided into two broad phylogenetic groups, referred to as red-like and green-like, based on deduced large subunit amino acid sequences. Unlike the form I enzyme from the closely related organism Rhodobacter sphaeroides, the form I RubisCO from R. capsulatus is a member of the green-like group and closely resembles the enzyme from certain chemoautotrophic proteobacteria and cyanobacteria. As the enzymatic properties of this type of RubisCO have not been well studied in a system that offers facile genetic manipulation, we purified theR. capsulatus form I enzyme and determined its basic kinetic properties. The enzyme exhibited an extremely low substrate specificity factor, which is congruent with its previously determined sequence similarity to form I enzymes from chemoautotrophs and cyanobacteria. The enzymological results reported here are thus strongly supportive of the previously suggested horizontal gene transfer that most likely occurred between a green-like RubisCO-containing bacterium and a predecessor to R. capsulatus. Expression results from hybrid and chimeric enzyme plasmid constructs, made with large and small subunit genes fromR. capsulatus and R. sphaeroides, also supported the unrelatedness of these two enzymes and were consistent with the recently proposed phylogenetic placement of R. capsulatus form I RubisCO. The R. capsulatus form I enzyme was found to be subject to a time-dependent fallover in activity and possessed a high affinity for CO2, unlike the closely similar cyanobacterial RubisCO, which does not exhibit fallover and possesses an extremely low affinity for CO2. These latter results suggest definite approaches to elucidate the molecular basis for fallover and CO2 affinity.

scholarly journals Comparison of the effects of Ca2+, adenine nucleotides and pH on the kinetic properties of mitochondrial NAD+-isocitrate dehydrogenase and oxoglutarate dehydrogenase from the yeast Saccharomyces cerevisiae and rat heart

1994 ◽  
Vol 303 (2) ◽  
pp. 461-465 ◽  
Author(s):  
B J Nichols ◽  
M Rigoulet ◽  
R M Denton
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Isocitrate Dehydrogenase ◽  
Rat Heart ◽  
Adenine Nucleotides ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Yeast Saccharomyces Cerevisiae ◽  
Rat Heart Mitochondria ◽  
Oxoglutarate Dehydrogenase ◽  
Regulatory Properties

The regulatory properties of NAD(+)-isocitrate dehydrogenase and oxoglutarate dehydrogenase in extracts of yeast and rat heart mitochondria were studied under identical conditions. Yeast NAD(+)-isocitrate dehydrogenase exhibits a low K0.5 for isocitrate and is activated by AMP and ADP, but is insensitive to ATP and Ca2+. In contrast, the rat heart NAD(+)-isocitrate dehydrogenase was insensitive to AMP, but was activated by ADP and by Ca2+ in the presence of ADP or ATP. Both yeast and rat heart oxoglutarate dehydrogenase were stimulated by ADP, but only the heart enzyme was activated by Ca2+. All the enzymes studied were activated by decreases in pH, but to differing extents. The effects of Ca2+, adenine nucleotides and pH were through K0.5 for isocitrate or 2-oxoglutarate. These observations are discussed with reference to the deduced amino acid sequences of the constituent subunits of the enzymes, where they are available.

scholarly journals Structural and Kinetic Properties of Nonglycosylated Recombinant Penicillium amagasakienseGlucose Oxidase Expressed in Escherichia coli

1998 ◽  
Vol 64 (4) ◽  
pp. 1405-1411 ◽  
Author(s):  
Susanne Witt ◽  
Mahavir Singh ◽  
Henryk M. Kalisz
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Pcr Amplification ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Peptide Fragments ◽  
Thermal Stabilities ◽  
E Coli

ABSTRACT The gene coding for Penicillium amagasakiense glucose oxidase (GOX; β-d-glucose; oxygen 1-oxidoreductase [EC1.1.3.4 ]) has been cloned by PCR amplification with genomic DNA as template with oligonucleotide probes derived from amino acid sequences of N- and C-terminal peptide fragments of the enzyme. RecombinantEscherichia coli expression plasmids have been constructed from the heat-induced pCYTEXP1 expression vector containing the mature GOX coding sequence. When transformed into E. coli TG2, the plasmid directed the synthesis of 0.25 mg of protein in insoluble inclusion bodies per ml of E. coli culture containing more than 60% inactive GOX. Enzyme activity was reconstituted by treatment with 8 M urea and 30 mM dithiothreitol and subsequent 100-fold dilution to a final protein concentration of 0.05 to 0.1 mg ml−1 in a buffer containing reduced glutathione-oxidized glutathione, flavin adenine dinucleotide, and glycerol. Reactivation followed first-order kinetics and was optimal at 10°C. The reactivated recombinant GOX was purified to homogeneity by mild acidification and anion-exchange chromatography. Up to 12 mg of active GOX could be purified from a 1-liter E. coli culture. Circular dichroism demonstrated similar conformations for recombinant and native P. amagasakiense GOXs. The purified enzyme has a specific activity of 968 U mg−1 and exhibits kinetics of glucose oxidation similar to those of, but lower pH and thermal stabilities than, native GOX from P. amagasakiense. In contrast to the native enzyme, recombinant GOX is nonglycosylated and contains a single isoform of pI 4.5. This is the first reported expression of a fully active, nonglycosylated form of a eukaryotic, glycosylated GOX inE. coli.

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