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At least 19 recordsLinked to original sources
PubMed1992

Phylogenetic position of phylum Nemertini, inferred from 18S rRNA sequences: molecular data as a test of morphological character homology.

Partial 18S rRNA sequence of the nemertine Cerebratulus lacteus was obtained and compared with those of coelomate metazoans and acoelomate platyhelminths to test whether nemertines share a most recent common ancestor with the platyhelminths, as traditionally has been implied, or whether nemertines lie within a protostome coelomate clade, as suggested by more recent morphological analyses. Maximum-parsimony analysis supports the inclusion of the nemertine within a protostome-coelomate clade that falls within a more inclusive coelomate clade. Bootstrap analysis indicates strong support for a monophyletic Coelomata composed of a deuterostome and protostome-coelomate clade. Support for a monophyletic protostome Coelomata is weak. Inference by distance analysis is consistent with that of maximum parsimony. Analysis of down-weighted paired sites by maximum parsimony reveals variation in topology only within the protostome-coelomate clade. The relationships among the protostome coelomates cannot be reliably inferred from the partial sequences, suggesting that coelomate protostomes diversified rapidly. Results with evolutionary parsimony are consistent with the inclusion of the nemertine in a coelomate clade. The molecular inference corroborates recent morphological character analyses that reveal no synapomorphies of nemertines and flatworms but instead suggest that the circulatory system and rhynchocoel of nemertines are homologous to coelomic cavities of protostome coelomates, thus supporting the corresponding hypothesis that nemertines belong within a protostome-coelomate clade. The sequence data provide an independent test of morphological character homology.

Animals↗
PubMed1992

Molecular sequence accuracy: analysing imperfect data.

Molecular sequences are experimentally derived data that can be expected to contain errors as a result of diverse phenomena such as biological variation, molecular cloning artifacts, imperfect sequence determination, and data handling during contig assembly. Errors will affect the reliability of database searches and sequence alignments, but their impact may be minimized by the use of analytical techniques that anticipate that the data will be imperfect.

Amino Acid Sequence↗
PubMed1991

Phylogenetic relationships within the class Oligohymenophorea, phylum Ciliophora, inferred from the complete small subunit rRNA gene sequences of Colpidium campylum, Glaucoma chattoni, and Opisthonecta henneguyi.

Phylogenetic relationships within the class Oligohymenophorea, phylum Ciliophora, were investigated by determining the complete small subunit rRNA (SSrRNA) gene sequences for the hymenostomes Colpidium campylum, Glaucoma chattoni, and the peritrich Opisthonecta henneguyi. The affiliations of the oligohymenophoreans were assessed using both distance matrix (DM) and maximum parsimony (MP) analyses. Variations do exist in the phylogenies created by the two methods. However, the basic tree topologies are consistent. In both the DM and MP analyses the hymenostomes (C. campylum, G. chattoni, and the tetrahymenas) all form a very tight group associated with the peritrich O. henneguyi. The Tetrahymena lineage was monophyletic whereas Colpidium and Glaucoma were more closely related to each other than either was to the tetrahymenas. The monophyly of the genus Tetrahymena in the present analysis supports the phylogenies determined from morphological data and molecular sequence data from the histone H3II/H4II region of the genome. The perplexing and controversial phylogenetic position of the peritrichs is once again depicted in the present analysis. The distinctiveness of the peritrich Opisthonecta from both hymenostome and nassophorean ciliates based on evolutionary distances suggests that the elevation of the peritrichs to a higher taxonomic rank should be reconsidered.

Animals↗
PubMed1991

Nucleotide sequence and characterization of the gene for secreted alkaline phosphatase from Lysobacter enzymogenes.

Lysobacter enzymogenes produces an alkaline phosphatase which is secreted into the medium. The gene for the enzyme (phoA) was isolated from a recombinant lambda library. It was identified within a 4.4-kb EcoRI-BamH1 fragment, and its sequence was determined by the chain termination method. The structural gene consists of an open reading frame which encodes a 539-amino-acid protein with a 29-residue signal sequence, followed by a 119-residue propeptide, the 281-residue mature phosphatase, and a 110-residue carboxy-terminal domain. The roles of the propeptide and the carboxy-terminal peptide remain to be determined. A molecular weight of 30,000 was determined for the mature enzyme from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amino acid sequence was compared with sequences available in the current protein data base, and a region of the sequence was found to show considerable homology with sequences in mammalian type 5 iron-containing purple acid phosphatases.

Alkaline Phosphatase↗
PubMed1990

Mitochondrial creatine kinase from chicken brain. Purification, biophysical characterization, and generation of heterodimeric and heterooctameric molecules with subunits of other creatine kinase isoenzymes.

In a recent study it has been shown that mitochondrial creatine kinase from chicken brain (Mia-CK) and heart (Mib-CK) are two distinct isoenzymes differing in ten out of the thirty N-terminal amino acids (Hossle, J.P., Schlegel, J., Wegmann, G., Wyss, M., Böhlen, P., Eppenberger, H.M., Wallimann, T., and Perriard J.C. (1988) Biochem. Biophys. Res. Commun. 151, 408-416). The present article describes the purification and biophysical characterization of the mitochondrial creatine kinase isoenzyme from chicken brain (Mia-CK). Gel permeation chromatography, direct mass measurements of individual molecules by scanning transmission electron microscopy, and analytical ultracentrifugation confirmed the existence of two different oligomeric forms, dimeric and octameric Mia-CK, with molecular masses of 85 kDa and 306-352 kDa and with sedimentation constants of 4.9-5.3 and 11.6-12.0 S, respectively. In addition, it was tested if Mia- and Mib-CK can form heterodimeric and heterooctameric molecules with subunits of other CK isoenzymes. By denaturation in urea or guanidine hydrochloride and subsequent renaturation, MiaMib-CK and surprisingly also MiaM-CK heterodimers could be generated. In contrast, no heterodimers were obtained between Mib- and M- or B-CK. Furthermore, reoctamerization of a mixture of Mia- and Mib-CK homodimers led to the formation of MiaMib-CK heterooctamers. In these heterooctamers, the Mia- and Mib-CK homodimers remained the fundamental building blocks. No subunit exchange between adjacent dimers within the heterooctamer could be observed even after storage for 3 months at 4 degrees C. The relevance of these data on the structural organization of the Mi-CK octamer and on the physiological aspects of tissue-specific isoenzyme expression are discussed.

Amino Acid Sequence↗
PubMed1990

The major non-integrin laminin binding protein of macrophages is identical to carbohydrate binding protein 35 (Mac-2).

Current data indicate that cell adhesion to laminin, the major basement membrane glycoprotein, is mediated by specific integrins, a family of adhesion receptors. In addition, most cell types express a complement of high affinity non-integrin laminin binding proteins (LBPs). Despite considerable effort, the function of these LBPs has not been elucidated. We report here that the major non-integrin LBP of murine macrophages exhibits an Mr of 35,000 and is expressed on the cell surface. Protein microsequencing data revealed that this protein is identical to carbohydrate binding protein 35. This murine galactose-specific lectin is the macrophage antigen Mac-2. Thus, these data suggest that the non-integrin LBPs may contribute to laminin adhesion by a mechanism involving protein-carbohydrate interactions.

Amino Acid Sequence↗
PubMed1989

Ornitho-kininogen and ornitho-kinin: isolation, characterization and chemical structure.

Ornitho-kininogen was purified from chicken and duck blood plasmas by a two-stage method using chromatography on columns of S-alkylated papain-Cellulofine and DEAE-5PW. The isolated preparation from chicken plasma gave a single band on SDS-PAGE with or without 2-mercaptoethanol and on disc-PAGE. The molecular weight of ornitho-kininogen was estimated as 74,000 on SDS-PAGE using the Ferguson plot method. Ornitho-kininogen was found to have the similar properties to those of mammalian high molecular weight kininogen (HMWK), in terms of the amino acid composition, molecular weight, and susceptibility to plasma kallikrein. No kininogen corresponding to mammalian low molecular weight kininogen (LMWK) and rat T-kininogen could be detected in chicken plasma. In fact, ornitho-kininogen was degraded rapidly by bovine plasma kallikrein, liberating a kinin. This kinin was isolated from the digest by reversed-phase HPLC. The primary structure of the isolated kinin was determined as Arg-Pro-Pro-Gly-Phe-Thr-Pro-Leu-Arg. The sequence of this peptide, named ornitho-kinin, was similar to that of bradykinin except for the substitution of Thr-6 and Leu-8 for Ser-6 and Phe-8. The isolated ornitho-kinin induced a contraction of chicken smooth muscle and had a strong hypotensive effect in the chicken. However, it did not contract the isolated rat uterus. It is suggested that this specificity difference is due to the replacement of Phe-8 by Leu-8. The sequence of residues 1-30 of ornitho-kininogen exhibited 43% identity with that of bovine kininogen.

Amino Acid Sequence↗
PubMed1992

Characterization of urease from Sporosarcina ureae.

Alkaline stable (pH 7.75-12.5) urease from Sporosarcina ureae was purified over 400-fold by ion exchange and hydrophobic interaction chromatography. The cytoplasmic enzyme was remarkably active with a specific activity of greater than 9300 mumol urea degraded min-1 mg protein-1 at pH 7.5, where it has optimal activity. Although S. ureae is closely related to Bacillus pasteurii, known to possess a homopolymeric urease containing 1 nickel per subunit [M(r) = 65000], the S. ureae enzyme is comprised of three subunits [apparent M(r) = 63,100 (alpha), 14,500 (beta), and 8500 (gamma)] in an estimated alpha beta gamma 2 stoichiometry and contains 2.1 +/- 0.6 nickel ions per alpha beta gamma 2 unit as measured by atomic absorption spectrometry. Stationary phase cultures sometimes possessed low levels of urease activity, but the specific activity of cell extracts of partially purified urease preparations from such cultures could be elevated by heat treatment, dilution, or dialysis to values comparable to those observed in samples from exponentially grown cells.

Amino Acid Sequence↗
PubMed1990

Identification and nucleotide sequence of the Acinetobacter calcoaceticus encoded trpE gene.

The trpE gene from Acinetobacter calcoaceticus encoding the anthranilate synthase component I was cloned, identified by deletion analysis and sequenced. It encodes a predicted polypeptide of 497 amino acids with a calculated molecular weight of 55,323. Its primary structure shows 49% identical amino acids with the enzyme from Clostridium thermocellum, 45% with that of Thermus thermophilus and only 35% with that of Escherichia coli. The codon usage of the trpE genes encoding the most homologous enzymes differs greatly indicating selection for amino acid maintainance. The homologies are clustered in the C-terminal 200 amino acids of the sequences indicating that this part is important for enzymic activity.

Acinetobacter↗
PubMed1991

Structural diversity of trypsin from different mosquito species feeding on vertebrate blood.

Mosquito trypsin was purified using a combination of ion exchange and affinity chromatography with the ligand soybean trypsin inhibitor. Three Aedes and three Anopheles species were tested, all of which are specialized in the digestion of vertebrate blood. Amino-terminal sequences of HPLC-purified trypsins from Aedes aegypti and Anopheles quadrimaculatus revealed homologies of 30-40% with vertebrate and other invertebrate proteases previously identified as serine-proteases. The purified mosquito trypsins have molecular masses between 25 kDa and 36 kDa, as determined by denaturing polyacrylamide electrophoresis, and are heterogeneous in size and number in the various species. The number of SDS-bands varies between 3 and 6 in Aedes and between 1 and 3 in Anopheles. The specific activities, determined with the substrate TAME, range from 240 U/mg in Aedes aegypti to 1065 U/mg in Anopheles quadrimaculatus. All mosquito trypsins tested have acidic isoelectric points between pH 3.5 and pH 5.4. No alkaline proteases were detected. Polyclonal antisera against Aedes aegypti and Anopheles albimanus trypsin do not cross-react with bovine trypsin. Cross-reactivity of the two sera with trypsin from six mosquito species suggests the presence of at least 2 enzyme families.

Aedes↗
PubMed1990

Characterization of molecular species of liver microsomal carboxylesterases of several animal species and humans.

Seven carboxylesterase isozymes were purified to electrophoretic homogeneity from liver microsomes of mouse, hamster, guinea pig, rabbit, and monkey by the same procedure used previously to obtain three isozymes from the rat, and their physical, enzymological, and immunological properties were compared with those of the rat isozymes. The substrate specificity and immunological reactivity of liver microsomal carboxylesterases from pig, cow, beagle dog, and human were also examined for comparison, though these enzymes were not purified. The ten purified preparations have similar subunit weight (57,000-64,000), but their isoelectric points differ widely (4.7-6.5). The purification procedure of all isozymes included concanavalin A-Sepharose column chromatography. The isozymes were not eluted from the column with a high concentration of sodium chloride, but were efficiently eluted with alpha-methylmannoside. This observation suggested that the carboxylesterases studied are glycoproteins. All the isozymes except rat RL1 and RL2 possess a high hydrolytic activity toward all the substrates examined. Long-chain monoglyceride was hydrolyzed by the purified carboxylesterase isozymes. Anti-rat RH1 immunoglobulin G was found to possess high cross-reactivity with all isozymes tested, except monkey MK2, by immunoblotting analysis. The amino acid compositions of carboxylesterase isozymes showed considerable similarities, except for monkey MK2. The amino-terminal amino acid sequences showed a striking homology, except for monkey MK2, though the amino-terminal amino acid itself was different in every isozyme. Hepatic microsomal carboxylesterases in mammals play an important role in drug and lipid metabolism in the endoplasmic reticulum, and it is noteworthy that the isozymes from various species examined here showed considerable similarities in physical, enzymatic, and immunochemical properties.

Amino Acid Sequence↗
PubMed1991

Ustilago maydis virus P4 killer toxin: characterization, partial amino terminus sequence, and evidence for glycosylation.

The toxin from Ustilago maydis virus P4 was purified to homogeneity and characterized. The native molecular mass, using size-exclusion HPLC was estimated to be 7.2 kDa. The purified toxin was composed of a single subunit. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis under reduced and nonreduced conditions resulted in estimated molecular masses of 8.4 and 7.4 kDa, respectively. The purified toxin was found to be glycosylated when tested for carbohydrates using the phenol-sulfuric acid method, Schiff's base reagent, and a Glycan detection kit and when probed against different biotinylated lectins. Partial amino acid sequence analysis of the purified toxin indicated a free N-terminus, 16% glycine, and 23% basic amino acid residues. No homology was found to either the alpha or the beta subunit of the toxin encoded by U. maydis infected with the P6 virus.

Amino Acid Sequence↗
PubMed1987

Purification and characterization of human liver cytochrome P-450-ALC.

Cytochrome P-450-ALC, an ethanol-oxidizing form of microsomal cytochrome P-450 (P-450), has been purified from human liver. P-450-ALC (Mr = 54,000 daltons) is a low-spin ferric hemeprotein with a CO-reduced Soret maximum at 452 nm, and has an NH2-terminal amino acid sequence nearly identical to that deduced from a human P-450-ALC cDNA clone. In a reconstituted system, P-450-ALC oxidizes ethanol and aniline at turnover rates (12.2 and 7.3 nmol min-1, respectively) 10-fold greater than two other human P-450 isozymes (termed P-450-B and P-450-C) purified from the same liver. Both P-450-ALC and P-450-C effectively demethylate N-nitrosodimethylamine (NDMA) at low substrate concentrations (0.5 mM), especially in the presence of cytochrome b5. Our results provide direct evidence for a liver P-450 isozyme in humans with catalytic properties similar to the related alcohol-inducible rodent P-450s and also reveal a new human NDMA demethylase.

Amino Acid Sequence↗
PubMed1990

Amyloid protein in familial amyloidosis (Finnish type) is homologous to gelsolin, an actin-binding protein.

Familial amyloidosis, Finnish type, is clinically characterized by cranial neuropathy and lattice corneal dystrophy. It is an autosomal dominant form of systemic amyloidosis with small deposits of congophilic material occurring in most tissues, particularly in association with blood vessel walls and basement membranes. Amyloid fibrils were extracted from the kidney of patient VUO, and rabbit antiserum raised against the 12 kDa purified amyloid subunit displayed strong immunohistochemical reactivity with the amyloid deposits. The amino terminal sequence of this 12 kDa amyloid protein (ATEVPVSWESFNNGD) showed homology with gelsolin (or actin depolymerizing factor), a 93 kDa plasma protein. The amyloid peptide is a degradation product, starting at position 173, of the gelsolin molecule.

Actins↗
PubMed1990

Purification of a cytochrome P450 isozyme belonging to a subfamily of P450 IIB from liver microsomes of guinea pigs.

An isozyme of cytochrome P450 was purified from liver microsomes of guinea pigs by HPLC with anion-exchange and hydroxylapatite columns. The isozyme showed a single band of 52 kdalton on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Oxidation activities of the final preparation towards p-nitroanisole, aniline and d-benzphetamine were 1.3 to 15.4-fold comparing with those of microsomal fraction. This isozyme was also concerned with oxidation of delta 9-tetrahydrocannabinol (THC) to 8 alpha-hydroxy- (8 alpha-OH-), 2'-OH- and 3'-OH-delta 9-THCs. The N-terminal region of the isozyme was considerably hydrophobic, and 13 of the first 20 amino acid residues was leucine. Since this first 20 amino acid sequence is 80% homologous with that of cytochrome P450 LM2 purified from rabbit liver microsomes, this isozyme can be categorized to a subfamily of P450 IIB.

Amino Acid Sequence↗
PubMed1990

The amino terminal sequence of the developmentally regulated Ch21 protein shows homology with amino terminal sequences of low molecular weight proteins binding hydrophobic molecules.

Ch21 protein, a developmentally regulated chick embryo protein of 21,000 apparent molecular weight, was purified from culture medium of hypertrophic chondrocytes. The purification method included a DEAE cellulose chromatography column, a CM cellulose chromatography column and a HPLC molecular sieve column. The amino acid sequence of the amino terminal end of the protein was determined. Computer assisted analysis showed significant homology between this sequence and the amino terminal sequences of proteins that belong to the superfamily of the low molecular weight binding proteins sharing a basic framework for the binding and transport of small hydrophobic molecules. Determination of the amino terminal sequence of the chicken retinol binding protein excluded identity between this protein and the Ch21.

Amino Acid Sequence↗