scholarly journals Expression of rat liver ketohexokinase in yeast results in fructose intolerance

1993 ◽  
Vol 291 (1) ◽  
pp. 179-186 ◽  
Author(s):  
I A Donaldson ◽  
T C Doyle ◽  
N Matas

Rat liver ketohexokinase (ATP:D-fructose 1-phosphotransferase; EC 2.7.1.3) was purified to homogeneity and the molecular mass of the protein was found by mass spectrometry to be 32,800 Da. The enzyme was cleaved and the amino acid sequences of seven peptides, comprising 24% of the total sequence, were determined. This sequence information was used to design oligonucleotide primers for a PCR using rat liver single-stranded cDNA as a template. The 224 bp PCR product was used as a probe to screen a rat liver cDNA library. A cDNA sequence of 1342 bp was obtained from three positive clones. This contained the entire coding region for ketohexokinase, and all seven peptides were identified in the predicted amino acid sequence. When ketohexokinase was expressed in Saccharomyces cerevisiae using the yeast expression vector pMA91, the cells became intolerant of the presence of fructose in their growth media. The growth of an exponential-phase culture was completely arrested within 90 min by the addition of fructose to a final concentration as low as 0.1% (w/v). This response is associated with an accumulation of fructose 1-phosphate. The cDNA for ketohexokinase encodes a protein composed of 299 amino acids with a combined molecular mass of 32,728 Da. This is in close agreement with the value for the isolated protein determined by mass spectrometry. The primary structure does not show any significant homology with those of other eukaryotic hexokinases, but it contains a highly conserved region that is present in three prokaryotic phosphotransferases that have furanose substrates.

1997 ◽  
Vol 326 (3) ◽  
pp. 883-889 ◽  
Author(s):  
Werner SCHMITZ ◽  
Heli M. HELANDER ◽  
J. Kalervo HILTUNEN ◽  
Ernst CONZELMANN

cDNA species coding for α-methylacyl-CoA racemase were cloned from rat and mouse liver cDNA libraries and characterized. The rat liver λgt11 cDNA expression library was screened with anti-racemase IgG [Schmitz, Albers, Fingerhut and Conzelmann (1995) Eur. J. Biochem. 231, 815–822]. Several full-length clones were obtained that contained an open reading frame of 1083 bp, coding for a protein of 361 amino acid residues with a predicted molecular mass of 39679 Da. The sequences of three peptides that were isolated by HPLC from a tryptic digest of purified rat liver racemase fully matched the cDNA-derived amino acid sequence. The cDNA coding for mouse racemase was cloned from a mouse liver λZAP cDNA expression library and sequenced. The coding region of 1080 bp codes for a 360-residue protein (molecular mass 39558 Da) that shares 89.7% similarity with the rat protein. Expression of the rat racemase as a recombinant protein in Escherichia coli with the pTrcHisB-expression vector yielded enzymically active protein. The amino acid sequences of α-methylacyl-CoA racemases do not resemble any known sequence of β-oxidation or auxiliary enzymes, supporting the view of a highly diverse evolutionary origin of enzymes acting on fatty acyl-CoA S-esters.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 1051-1061 ◽  
Author(s):  
Chaoqiang Lai ◽  
Robert McMahon ◽  
Chi Young ◽  
Trudy F C Mackay ◽  
Charles H Langley

Abstract The quemao (qm) locus of Drosophila melanogaster is characterized by a P-element-associated mutant lacking most of the large bristles on the thorax and by several EMS-induced recessive lethals. quemao was cloned using a transposon tagging strategy. P-element-mediated transformation demonstrated that the cloned qm DNA sequence (from the 65F cytological region) rescues the mutant phenotype. A 2.3-kb qm transcript was identified by Northern blot analysis by sequencing of the isolated qm cDNA clones and by 5′ rapid amplification cDNA end (RACE). The predicted amino acid sequence (338 residues) of the coding region of the qm transcript shares 42, 31, 13, 20, and 12% identical amino acid sequences with the geranylgeranyl pyrophosphate synthase (GGPPS) of fungi, yeast, plants, archaebacteria, and eubacteria, respectively. It also contains five highly conserved domains common among all known isoprenyl pyrophosphate synthases. The P element associated with the original qm mutant is inserted in the 5′ untranslated region of the transcript. An EMS-induced qm nonsense mutation at the 12th codon leads to recessive lethality at the first larval instar, indicating the essential role of qm in the isoprenoid biosynthesis of insects.


1992 ◽  
Vol 25 (2) ◽  
pp. 205-210 ◽  
Author(s):  
L. J. Keefe ◽  
E. E. Lattman ◽  
C. Wolkow ◽  
A. Woods ◽  
M. Chevrier ◽  
...  

Ambiguities in amino acid sequences are a potential problem in X-ray crystallographic studies of proteins. Amino acid side chains often cannot be reliably identified from the electron density. Many protein crystal structures that are now being solved are simple variants of a known wild-type structure. Thus, cloning artifacts or other untoward events can readily lead to cases in which the proposed sequence is not correct. An example is presented showing that mass spectrometry provides an excellent tool for analyzing suspected errors. The X-ray crystal structure of an insertion mutant of Staphylococcal nuclease has been solved to 1.67 Å resolution and refined to a crystallographic R value of 0.170 [Keefe & Lattman (1992). In preparation]. A single residue has been inserted in the C-terminal α helix. The inserted amino acid was believed to be an alanine residue, but the final electron density maps strongly indicated that a glycine had been inserted instead. To confirm the observations from the X-ray data, matrix-assisted laser desorption mass spectrometry was employed to verify the glycine insertion. This mass spectrometric technique has sufficient mass accuracy to detect the methyl group that distinguishes glycine from alanine and can be extended to the more common situation in which crystallographic measurements suggest a problem with the sequence, but cannot pinpoint its location or nature.


1986 ◽  
Vol 6 (3) ◽  
pp. 849-858 ◽  
Author(s):  
C B Shoemaker ◽  
L D Mitsock

The gene for murine erythropoietin (EPO) was isolated from a mouse genomic library with a human EPO cDNA probe. Nucleotide sequence analysis permitted the identification of the murine EPO coding sequence and the prediction of the encoded amino acid sequence based on sequence conservation between the mouse and human EPO genes. Both the coding DNA and the amino acid sequences were 80% conserved between the two species. Transformation of COS-1 cells with a mammalian cell expression vector containing the murine EPO coding region resulted in secretion of murine EPO with biological activity on both murine and human erythroid progenitor cells. The transcription start site for the murine EPO gene in kidneys was determined. This permitted tentative identification of the transcription control region. The region included 140 base pairs upstream of the cap site which was over 90% conserved between the murine and human genes. Surprisingly, the first intron and much of the 5'- and 3'-untranslated sequences were also substantially conserved between the genes of the two species.


1996 ◽  
Vol 49 (12) ◽  
pp. 1325 ◽  
Author(s):  
AM Bradford ◽  
JH Bowie ◽  
MJ Tyler ◽  
JC Wallace

The dorsal glandular extract of the toadlet Uperoleia mjobergii contains more than 20 peptides. We report the amino acid sequences of the seven major peptides: these were determined by a combination of mass spectrometry and automated Edman sequencing. Three of these peptides have 19 amino acid residues and belong to the uperin 2 group of peptides [e.g. uperin 2.6, Gly Ile Leu Asp Ile Ala Lys Lys Leu Val Gly Gly Ile Arg Asn Val Leu Gly Ile (OH)], while the other four have 17 residues and are classified as uperins 3 [e.g. Uperin 3.4, Gly Val Gly Asp Leu Ile Arg Lys Ala Val Ala Ala Ile Lys Asn Ile Val (NH2)]. Several of these cationic peptides have been synthesized in order for bioassays to be carried out: they show significant antibiotic activity against a range of Gram-positive microorganisms. A major skin peptide from the related species Uperoleia inundata is a powerful neuropeptide named uperin 1.1 ([Ala2] uperolein ): no corresponding neuropeptide is detected in the skin glands of Uperoleia mjobergii.


2000 ◽  
Vol 68 (7) ◽  
pp. 3941-3948 ◽  
Author(s):  
Tong-Soo Kim ◽  
Younghun Jung ◽  
Byoung-Kuk Na ◽  
Ki-Sun Kim ◽  
Pyung-Rim Chung

ABSTRACT The cytosolic superoxide dismutase (SOD) of Fasciola hepatica, a causative agent of fascioliasis, was purified and characterized. The enzyme consists of two identical subunits, each with an apparent molecular mass of 17.5 kDa. An analysis of the enzyme's primary structure and inhibition studies revealed that the enzyme is a copper/zinc-containing SOD (Cu/Zn-SOD). The enzyme activity was relatively stable in a broad pH range, from pH 7.0 to 10.0, and the enzyme showed maximum activity at pH 7.5. This enzyme also displayed strong antigenicity against sera of bovine and human subjects with fascioliasis. The SOD gene fragment was amplified by PCR with degenerate oligonucleotide primers derived from amino acid sequences conserved in the Cu/Zn-SODs of other organisms. An F. hepatica cDNA library was screened with the SOD gene fragment as a probe. As a result, a complete gene encoding the Cu/Zn-SOD was identified, and its nucleotide sequence was determined. The gene had an open reading frame of 438 bp and 146 deduced amino acids. Comparison of the deduced amino acid sequence of the enzyme with previously reported Cu/Zn-SOD amino acid sequences revealed considerably high homologies. The coding region of the F. hepatica Cu/Zn-SOD was cloned and expressed in Escherichia coli. Staining of native polyacrylamide gel for SOD activity of the expressed protein revealed SOD activity that was inactivated by potassium cyanide and hydrogen peroxide but not by sodium azide. This means that the presence of the recombinant fusion protein is indicative of Cu/Zn-SOD. The expressed protein also reacted with sera of bovine and human subjects with fascioliasis, but it did not react with sera of uninfected bovine and human subjects.


1986 ◽  
Vol 235 (3) ◽  
pp. 895-898 ◽  
Author(s):  
M S López de Haro ◽  
A Nieto

An almost full-length cDNA coding for pre-uteroglobin from hare lung was cloned and sequenced. The derived amino acid sequence indicated that hare pre-uteroglobin contained 91 amino acids, including a signal peptide of 21 residues. Comparison of the nucleotide sequence of hare pre-uteroglobin cDNA with that previously reported for the rabbit gene indicated five silent point substitutions and six others leading to amino acid changes in the coding region. The untranslated regions of both pre-uteroglobin mRNAs were very similar. The amino acid changes observed are discussed in relation to the different progesterone-binding abilities of both homologous proteins.


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