scholarly journals Cloning, sequencing and heterologous expression of the gene for lupanine hydroxylase, a quinocytochrome c from a Pseudomonas sp.

2002 ◽  
Vol 367 (2) ◽  
pp. 483-489 ◽  
Author(s):  
David J. HOPPER ◽  
Mustak A. KADERBHAI ◽  
Shirley A. MARRIOTT ◽  
Michael YOUNG ◽  
Jerzy ROGOZINSKI

The gene encoding the enzyme lupanine hydroxylase was isolated by PCR using chromosomal DNA from a lupanine-utilizing Pseudomonas sp. as template and primers based on the sequences of the N- and C-termini of the purified protein. The derived sequence for the mature gene product gave a protein with an Mr of 72256, in good agreement with the value found by SDS/PAGE of the pure enzyme, and contained the sequences of several peptides obtained after endoproteinase Lys-C digestion of the pure enzyme. The gene, under the transcriptional control of a phoA promotor and with the Escherichia coli alkaline phosphatase signal sequence, was expressed in E. coli containing a plasmid expressing the genes for cytochrome c maturation proteins constitutively. Haem-containing inactive protein in inclusion bodies was renatured and reactivated with pyrroloquinoline quinone (PQQ) and Ca2+ to give active enzyme. The lupanine hydroxylase (luh) gene coded for a protein with a cleavable 26-residue signal sequence at its N-terminus, required for the transport of the enzyme to its periplasmic location. Analysis of the protein sequence showed that it contains two domains, a large PQQ-binding N-terminal domain and a smaller cytochrome c C-terminal domain. Comparison of the derived sequence with those of other proteins showed considerable similarity with other quino(haemo)proteins, including alcohol dehydrogenases from a variety of bacteria. The PQQ-binding domain sequence contains W motifs, characteristic of the eight-bladed ‘propeller’ structure of methanol dehydrogenase, but lacks the unusual disulphide ring structure formed from two adjacent cysteines seen in this enzyme. The C-terminus shares some similarity with bacterial cytochrome c and includes the haem-binding consensus sequence CXXCH.

1994 ◽  
Vol 5 (9) ◽  
pp. 1023-1037 ◽  
Author(s):  
H Bénédetti ◽  
S Raths ◽  
F Crausaz ◽  
H Riezman

Two Saccharomyces cerevisiae mutants, end3 and end4, defective in the internalization step of endocytosis, have previously been isolated. The END3 gene was cloned by complementation of the temperature-sensitive growth defect caused by the end3 mutation and the END3 nucleotide sequence was determined. The END3 gene product is a 40-kDa protein that has a putative EF-hand Ca(2+)-binding site, a consensus sequence for the binding of phosphotidylinositol 4,5-bisphosphate (PIP2), and a C-terminal domain containing two homologous regions of 17-19 aa. The EF-hand consensus and the putative PIP2-binding sites are seemingly not required for End3 protein function. In contrast, different portions of the End3p N-terminal domain, and at least one of the two repeated regions in its C-terminus, are required for End3p activity. Disruption of the END3 gene yielded cells with the same phenotype as the original end3 mutant. An end3ts allele was obtained and this allowed us to demonstrate that End3p is specifically involved in the internalization step of endocytosis. In addition, End3p was shown to be required for proper organization of the actin cytoskeleton and for the correct distribution of chitin at the cell surface.


2004 ◽  
Vol 70 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Laura-Leena Kiiskinen ◽  
Markku Saloheimo

ABSTRACT The lac1 gene encoding an extracellular laccase was isolated from the thermophilic fungus Melanocarpus albomyces. This gene has five introns, and it encodes a protein consisting of 623 amino acids. The deduced amino acid sequence of the laccase was shown to have high homology with laccases from other ascomycetes. In addition to removal of a putative 22-amino-acid signal sequence and a 28-residue propeptide, maturation of the translation product of lac1 was shown to involve cleavage of a C-terminal 14-amino-acid extension. M. albomyces lac1 cDNA was expressed in Saccharomyces cerevisiae under the inducible GAL1 promoter. Extremely low production was obtained with the expression construct containing laccase cDNA with its own signal and propeptide sequences. The activity levels were significantly improved by replacing these sequences with the prepro sequence of the S. cerevisiae α-factor gene. The role of the C-terminal extension in laccase production in S. cerevisiae was also studied. Laccase production was increased sixfold with the modified cDNA that had a stop codon after the native processing site at the C terminus.


1999 ◽  
Vol 181 (7) ◽  
pp. 2084-2093 ◽  
Author(s):  
Edita Sužiede˙liene˙ ◽  
Ke˛stutis Sužiede˙lis ◽  
Vaida Garbenčiute˙ ◽  
Staffan Normark

ABSTRACT Escherichia coli responds to external acidification (pH 4.0 to 5.0) by synthesizing a newly identified, ∼450-nucleotide RNA component. At maximal levels of induction it is one of the most abundant small RNAs in the cell and is relatively stable bacterial RNA. The acid-inducible RNA was purified, and the gene encoding it, designated asr (for acid shock RNA), mapped at 35.98 min on the E. coli chromosome. Analysis of the asr DNA sequence revealed an open reading frame coding for a 111-amino-acid polypeptide with a deduced molecular mass of approximately 11.6 kDa. According to computer-assisted analysis, the predicted polypeptide contains a typical signal sequence of 30 amino acids and might represent either a periplasmic or an outer membrane protein. Theasr gene cloned downstream from a T7 promoter was translated in vivo after transcription using a T7 RNA polymerase transcription system. Expression of a plasmid-encodedasr::lacZ fusion under a nativeasr promoter was reduced ∼15-fold in a complex medium, such as Luria-Bertani medium, versus the minimal medium. Transcription of the chromosomal asr was abolished in the presence of aphoB-phoR (a two-component regulatory system, controlling the pho regulon inducible by phosphate starvation) deletion mutant. Acid-mediated induction of the asr gene in the Δ(phoB-phoR) mutant strain was restored by introduction of the plasmid with cloned phoB-phoR genes. Primer extension analysis of the asr transcript revealed a region similar to the Pho box (the consensus sequence found in promoters transcriptionally activated by the PhoB protein) upstream from the determined transcription start. The asr promoter DNA region was demonstrated to bind PhoB protein in vitro. We discuss our results in terms of how bacteria might employ the phoB-phoRregulatory system to sense an external acidity and regulate transcription of the asr gene.


2012 ◽  
Vol 11 (8) ◽  
pp. 1055-1066 ◽  
Author(s):  
Matthias Kretschmer ◽  
Jana Klose ◽  
James W. Kronstad

ABSTRACTAn understanding of metabolic adaptation during the colonization of plants by phytopathogenic fungi is critical for developing strategies to protect crops. Lipids are abundant in plant tissues, and fungal phytopathogens in the phylum basidiomycota possess both peroxisomal and mitochondrial β-oxidation pathways to utilize this potential carbon source. Previously, we demonstrated a role for the peroxisomal β-oxidation enzyme Mfe2 in the filamentous growth, virulence, and sporulation of the maize pathogenUstilago maydis. However,mfe2mutants still caused disease symptoms, thus prompting a more detailed investigation of β-oxidation. We now demonstrate that a defect in thehad1gene encoding hydroxyacyl coenzyme A dehydrogenase for mitochondrial β-oxidation also influences virulence, although its paralog,had2, makes only a minor contribution. Additionally, we identified a gene encoding a polypeptide with similarity to the C terminus of Mfe2 and designated it Mfe2b; this gene makes a contribution to virulence only in the background of anmfe2Δ mutant. We also show that short-chain fatty acids induce cell death inU. maydisand that a block in β-oxidation leads to toxicity, likely because of the accumulation of toxic intermediates. Overall, this study reveals that β-oxidation has a complex influence on the formation of disease symptoms byU. maydisthat includes potential metabolic contributions to proliferationin plantaand an effect on virulence-related morphogenesis.


2015 ◽  
Vol 145 (4) ◽  
pp. 303-314 ◽  
Author(s):  
Joshua D. Ohrtman ◽  
Christin F. Romberg ◽  
Ong Moua ◽  
Roger A. Bannister ◽  
S. Rock Levinson ◽  
...  

CaV1.1 acts as both the voltage sensor that triggers excitation–contraction coupling in skeletal muscle and as an L-type Ca2+ channel. It has been proposed that, after its posttranslational cleavage, the distal C terminus of CaV1.1 remains noncovalently associated with proximal CaV1.1, and that tethering of protein kinase A to the distal C terminus is required for depolarization-induced potentiation of L-type Ca2+ current in skeletal muscle. Here, we report that association of the distal C terminus with proximal CaV1.1 cannot be detected by either immunoprecipitation of mouse skeletal muscle or by colocalized fluorescence after expression in adult skeletal muscle fibers of a CaV1.1 construct labeled with yellow fluorescent protein (YFP) and cyan fluorescent protein on the N and C termini, respectively. We found that L-type Ca2+ channel activity was similar after expression of constructs that either did (YFP-CaV1.11860) or did not (YFP-CaV1.11666) contain coding sequence for the distal C-terminal domain in dysgenic myotubes null for endogenous CaV1.1. Furthermore, in response to strong (up to 90 mV) or long-lasting prepulses (up to 200 ms), tail current amplitudes and decay times were equally increased in dysgenic myotubes expressing either YFP-CaV1.11860 or YFP-CaV1.11666, suggesting that the distal C-terminal domain was not required for depolarization-induced potentiation. Thus, our experiments do not support the existence of either biochemical or functional interactions between proximal CaV1.1 and the distal C terminus.


2001 ◽  
Vol 183 (6) ◽  
pp. 1954-1960 ◽  
Author(s):  
Grit Zarnt ◽  
Thomas Schräder ◽  
Jan R. Andreesen

ABSTRACT The quinohemoprotein tetrahydrofurfuryl alcohol dehydrogenase (THFA-DH) from Ralstonia eutropha strain Bo was investigated for its catalytic properties. The apparentk cat/Km andK i values for several substrates were determined using ferricyanide as an artificial electron acceptor. The highest catalytic efficiency was obtained with n-pentanol exhibiting a k cat/Km value of 788 × 104 M−1 s−1. The enzyme showed substrate inhibition kinetics for most of the alcohols and aldehydes investigated. A stereoselective oxidation of chiral alcohols with a varying enantiomeric preference was observed. Initial rate studies using ethanol and acetaldehyde as substrates revealed that a ping-pong mechanism can be assumed for in vitro catalysis of THFA-DH. The gene encoding THFA-DH from R. eutropha strain Bo (tfaA) has been cloned and sequenced. The derived amino acid sequence showed an identity of up to 67% to the sequence of various quinoprotein and quinohemoprotein dehydrogenases. A comparison of the deduced sequence with the N-terminal amino acid sequence previously determined by Edman degradation analysis suggested the presence of a signal sequence of 27 residues. The primary structure of TfaA indicated that the protein has a tertiary structure quite similar to those of other quinoprotein dehydrogenases.


1997 ◽  
Vol 137 (6) ◽  
pp. 1265-1278 ◽  
Author(s):  
Gary A. Eitzen ◽  
Rachel K. Szilard ◽  
Richard A. Rachubinski

Pex mutants of the yeast Yarrowia lipolytica are defective in peroxisome assembly. The mutant strain pex16-1 lacks morphologically recognizable peroxisomes. Most peroxisomal proteins are mislocalized to a subcellular fraction enriched for cytosol in pex16 strains, but a subset of peroxisomal proteins is localized at, or near, wild-type levels to a fraction typically enriched for peroxisomes. The PEX16 gene was isolated by functional complementation of the pex16-1 strain and encodes a protein, Pex16p, of 391 amino acids (44,479 D). Pex16p has no known homologues. Pex16p is a peripheral protein located at the matrix face of the peroxisomal membrane. Substitution of the carboxylterminal tripeptide Ser-Thr-Leu, which is similar to the consensus sequence of peroxisomal targeting signal 1, does not affect targeting of Pex16p to peroxisomes. Pex16p is synthesized in wild-type cells grown in glucose-containing media, and its levels are modestly increased by growth of cells in oleic acid–containing medium. Overexpression of the PEX16 gene in oleic acid– grown Y. lipolytica leads to the appearance of a small number of enlarged peroxisomes, which contain the normal complement of peroxisomal proteins at levels approaching those of wild-type peroxisomes.


Author(s):  
Qing He ◽  
Kang Wang ◽  
Tiantian Su ◽  
Feng Wang ◽  
Lichuan Gu ◽  
...  

VqsR is a quorum-sensing (QS) transcriptional regulator which controls QS systems (las,rhlandpqs) by directly downregulating the expression ofqscRinPseudomonas aeruginosa. As a member of the LuxR family of proteins, VqsR shares the common motif of a helix–turn–helix (HTH)-type DNA-binding domain at the C-terminus, while the function of its N-terminal domain remains obscure. Here, the crystal structure of the N-terminal domain of VqsR (VqsR-N; residues 1–193) was determined at a resolution of 2.1 Å. The structure is folded into a regular α–β–α sandwich topology, which is similar to the ligand-binding domain (LBD) of the LuxR-type QS receptors. Although their sequence similarity is very low, structural comparison reveals that VqsR-N has a conserved enclosed cavity which could recognize acyl-homoserine lactones (AHLs) as in other LuxR-type AHL receptors. The structure suggests that VqsR could be a potential AHL receptor.


2004 ◽  
Vol 186 (20) ◽  
pp. 6983-6998 ◽  
Author(s):  
Aneta A. Bartosik ◽  
Krzysztof Lasocki ◽  
Jolanta Mierzejewska ◽  
Christopher M. Thomas ◽  
Grazyna Jagura-Burdzy

ABSTRACT The par genes of Pseudomonas aeruginosa have been studied to increase the understanding of their mechanism of action and role in the bacterial cell. Key properties of the ParB protein have been identified and are associated with different parts of the protein. The ParB- ParB interaction domain was mapped in vivo and in vitro to the C-terminal 56 amino acids (aa); 7 aa at the C terminus play an important role. The dimerization domain of P. aeruginosa ParB is interchangeable with the dimerization domain of KorB from plasmid RK2 (IncP1 group). The C-terminal part of ParB is also involved in ParB-ParA interactions. Purified ParB binds specifically to DNA containing a putative parS sequence based on the consensus sequence found in the chromosomes of Bacillus subtilis, Pseudomonas putida, and Streptomyces coelicolor. The overproduction of ParB was shown to inhibit the function of genes placed near parS. This “silencing” was dependent on the parS sequence and its orientation. The overproduction of P. aeruginosa ParB or its N-terminal part also causes inhibition of the growth of P. aeruginosa and P. putida but not Escherichia coli cells. Since this inhibitory determinant is located well away from ParB segments required for dimerization or interaction with the ParA counterpart, this result may suggest a role for the N terminus of P. aeruginosa ParB in interactions with host cell components.


1989 ◽  
Vol 257 (6) ◽  
pp. L421-L429 ◽  
Author(s):  
H. P. Haagsman ◽  
R. T. White ◽  
J. Schilling ◽  
K. Lau ◽  
B. J. Benson ◽  
...  

SP-A, a glycoprotein of pulmonary surfactant, consists of an NH2-terminal domain containing a collagen-like sequence and a COOH-terminal domain with sequence homology to several Ca2(+)-dependent lectins. We have compared the size, thermal stability, and secondary structure of recombinant SP-A, the product of a fibroblast line transfected with a single human gene encoding SP-A, with natural SP-A isolated from canine and human lungs. Our results suggest both recombinant and natural SP-A are assembled as large oligomers. More variability in the degree of oligomerization was observed with recombinant human SP-A than with natural canine SP-A. As shown by collagenase digestion, the full assembly of protein subunits was dependent on an intact collagen-like domain. The cysteines in the noncollagen domain of SP-A form intrachain bonds between residues 135-226 and 204-218. The circular dichroism spectra of both recombinant and natural SP-A were consistent with the presence of a collagen-like triple helix. As determined by the change in ellipticity at 205 nm, the thermal transition temperatures of canine, natural human, and recombinant SP-A were 51.5, 52.3, and 42.0 degrees C, respectively. These results suggest differences in the assembly and stability of the natural and recombinant proteins.


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