scholarly journals Expression and characterization of recombinant fungal acetyl-CoA carboxylase and isolation of a soraphen-binding domain

2004 ◽  
Vol 380 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Stephanie C. WEATHERLY ◽  
Sandra L. VOLRATH ◽  
Tedd D. ELICH

Acetyl-CoA carboxylase (ACC) catalyses the first step in fatty-acid biosynthesis. Owing to its role in primary metabolism, ACC has been exploited as a commercial herbicide target and identified as a chemically validated fungicide target. In animals, ACC is also a key regulator of fat metabolism. This function has made ACC a prime target for the development of anti-obesity and anti-Type II diabetes therapeutics. Despite its economic importance, there is a lack of published information on recombinant expression of ACC. We report here the expression of enzymically active fungal (Ustilago maydis) ACC in Escherichia coli. The recombinant enzyme exhibited Km values of 0.14±0.013 mM and 0.19±0.041 mM for acetyl-CoA and ATP respectively, which are comparable with those reported for the endogenous enzyme. The polyketide natural product soraphen is a potent inhibitor of the BC (biotin carboxylase) domain of endogenous fungal ACC. Similarly, recombinant ACC activity was inhibited by soraphen with a Ki of 2.1±0.9 nM. A truncated BC domain that included amino acids 2–560 of the full-length protein was also expressed in E. coli. The isolated BC domain was expressed to higher levels, and was more stable than full-length ACC. Although incapable of enzymic turnover, the BC domain exhibited high-affinity soraphen binding (Kd 1.1±0.3 nM), demonstrating a native conformation. Additional BC domains from the phytopathogenic fungi Magnaporthe grisea and Phytophthora infestans were also cloned and expressed, and were shown to exhibit high-affinity soraphen binding. Together, these reagents will be useful for structural studies and assay development.

1996 ◽  
Vol 316 (3) ◽  
pp. 915-922 ◽  
Author(s):  
Jane WIDMER ◽  
Katherine S. FASSIHI ◽  
Susannah C. SCHLICHTER ◽  
Kate S. WHEELER ◽  
Barbara E. CRUTE ◽  
...  

Acetyl-CoA carboxylase (ACC), an important enzyme in fatty acid biosynthesis and a regulator of fatty acid oxidation, is present in at least two isoenzymic forms in rat and human tissues. Previous work has established the existence of a 265000 Da enzyme in both the rat and human (RACC265; HACC265) and a higher-molecular-mass species (275000–280000 Da) in the same species (RACC280; HACC275). An HACC265 gene has previously been localized to chromosome 17. In the present study, we report cloning of a partial-length human cDNA sequence which appears to correspond to HACC275 and its rat homologue, RACC280, as judged by mRNA tissue distribution and cell-specific regulation of mRNA/protein expression. The gene encoding this isoenzymic form of ACC has been localized to the long arm of human chromosome 12. Thus, ACC is represented in a multigene family in both rodents and humans. The newly discovered human gene and its rat homologue appear to be under different regulatory control to the HACC265 gene, as judged by tissue-specific expression in vivo and by independent modulation in cultured cells in vitro.


1994 ◽  
Vol 302 (3) ◽  
pp. 881-887 ◽  
Author(s):  
A Chapman-Smith ◽  
D L Turner ◽  
J E Cronan ◽  
T W Morris ◽  
J C Wallace

A protein segment consisting of the C-terminal 87 residues of the biotin carboxy carrier protein from Escherichia coli acetyl-CoA carboxylase was overexpressed in E. coli. The expressed biotin-domain peptide can be fully biotinylated by coexpression with a plasmid that overproduces E. coli biotin ligase. The extent of biotinylation was limited in vivo, but could be taken to completion in cell lysates on addition of ATP and biotin. We used the coexpression of biotin ligase and acceptor protein to label the biotin-domain peptide in vitro with [3H]biotin, which greatly facilitated development of a purification procedure. The apo (unbiotinylated) form of the protein was prepared by induction of biotin-domain expression in a strain lacking the biotin-ligase-overproduction plasmid. The apo domain could be separated from the biotinylated protein by ion-exchange chromatography or non-denaturing PAGE, and was converted into the biotinylated form of the peptide on addition of purified biotin ligase. The identify of the purified biotin-domain peptide was confirmed by N-terminal sequence analysis, amino acid analysis and m.s. The domain was readily produced and purified in sufficient quantities for n.m.r. structural analysis.


1988 ◽  
Vol 43 (1-2) ◽  
pp. 47-54 ◽  
Author(s):  
Klaus Kobek ◽  
Manfred Focke ◽  
K. Lichtenthaler Botanisches

The effect of the herbicides and aryloxy-phenoxy-propionic acid derivatives diclofop, fenoxaprop, fluazifop and haloxyfop and their ethyl, methyl or butyl esters on the de novo fatty-acid biosynthesis of isolated chloroplasts was investigated with intact chloroplasts isolated from sensitive grasses (Poaceae) and tolerant dicotyledonous plants (Pisum, Spinacia). The 4 herbicides (free-acid form) block the de novo fatty-acid biosynthesis ([2-14C]acetate incorporation into the total fatty-acid fraction) of the sensitive Avena chloroplasts in a dose-dependent manner. The I50- values (a 50% inhibition of the [14C]acetate incorporation) lie in the range of 10-7 to 2 x 10-6 ᴍ. The ethyl or methyl esters (diclofop, fenoxaprop, haloxyfop) and butyl ester (fluazifop) do not affect the de novo fatty-acid biosynthesis of isolated chloroplasts or only at a very high concentration of ca. 10-4 ᴍ. In contrast, the de novo fatty-acid biosynthesis of the tolerant dicotyledonous species (pea, spinach) is not affected by the 4 aryloxy-phenoxy-propionic acid herbicides. In an enzyme preparation isolated from chloroplasts of the herbicide-sensitive barley plants the de novo fatty-acid biosynthesis from [14C]acetate and [14C]acetyl-CoA is blocked by all 4 herbicides (free acids), whereas that of [14C]malonate and [14C]malonyl-CoA is not affected. This strongly suggests that the target of all 4 herbicides (free-acid form) is the acetyl-CoA carboxylase within the chloroplasts. The applied ester derivatives, in turn, which are ineffective in the isolated chloroplast test system, have equally little or no effect on the activity of the acetyl-CoA carboxylase. It is assumed that the acetyl-CoA carboxylase of the tolerant dicot plants investigated is modified in such a way that the 4 herbicides cannot bind to and affect the target


1993 ◽  
Vol 265 (2) ◽  
pp. L140-L147 ◽  
Author(s):  
Z. X. Xu ◽  
W. Stenzel ◽  
S. M. Sasic ◽  
D. A. Smart ◽  
S. A. Rooney

There are developmental and glucocorticoid-induced increases in the rate of fatty acid biosynthesis and in the activity of fatty acid synthase in late gestation fetal lung. We have now measured mRNA levels of fatty acid synthase and of two other enzymes of fatty acid biosynthesis, ATP citrate lyase and acetyl-CoA carboxylase, in developing fetal and postnatal rat lung and in fetal lung explants cultured with and without dexamethasone. There was a developmental increase in the mRNA for fatty acid synthase with the maximum level being reached on fetal day 21 (term is fetal day 22). This profile was similar to that reported for de novo fatty acid synthesis and fatty acid synthase activity. There was a similar but less pronounced developmental increase in the mRNA for ATP citrate lyase and a corresponding increase in its activity. There was no developmental change in the mRNA for acetyl-CoA carboxylase. Dexamethasone increased the level of fatty acid synthase mRNA approximately threefold but had no effect on those for ATP citrate lyase and acetyl-CoA carboxylase. The effect of dexamethasone on fatty acid synthase mRNA was rapid, biphasic, and partly inhibited by actinomycin D and cycloheximide. We conclude that glucocorticoids increase expression of the gene for fatty acid synthase in fetal lung. The effect of the hormone appears to be due to increased transcription and post-transcriptional events and is dependent on protein synthesis.


Structure ◽  
2013 ◽  
Vol 21 (4) ◽  
pp. 650-657 ◽  
Author(s):  
Tyler C. Broussard ◽  
Matthew J. Kobe ◽  
Svetlana Pakhomova ◽  
David B. Neau ◽  
Amanda E. Price ◽  
...  

1994 ◽  
Vol 301 (2) ◽  
pp. 599-605 ◽  
Author(s):  
K M Elborough ◽  
R Swinhoe ◽  
R Winz ◽  
J T Kroon ◽  
L Farnsworth ◽  
...  

One independent and two overlapping rape cDNA clones have been isolated from a rape embryo library. We have shown that they encode a 2.3 kb and a 2.5 kb stretch of the full-length acetyl-CoA carboxylase (ACCase) cDNA, corresponding to the biotin-binding and transcarboxylase domains respectively. Using the cDNA in Northern-blot analysis we have shown that the mRNA for ACCase has a higher level of expression in rape seed than in rape leaf and has a full length of 7.5 kb. The level of expression during rape embryogenesis was compared with both oil deposition and expression of two fatty acid synthetase components enoyl-(acyl-carrier-protein) reductase and 3-oxoacyl-(acyl-carrier-protein) reductase. Levels of ACCase mRNA were shown to peak at 29 days after anthesis during embryonic development, similarly to enoyl-(acyl-carrier-protein) reductase and 3-oxoacyl-(acyl-carrier-protein) reductase mRNA. In addition, a full-length genomic clone (19 kb) of Arabidopsis ACCase has been isolated and partially sequenced. Analysis of the clone has allowed the first plant ACCase activity domains (biotin carboxylase-biotin binding-transcarboxylase) to be ordered and assigned. Southern-blot analysis using the Arabidopsis clone indicates that ACCase is a single-copy gene in Arabidopsis but is encoded by a small gene family in rape.


1984 ◽  
Vol 56 (4) ◽  
pp. 1060-1064 ◽  
Author(s):  
R. Scorpio ◽  
R. L. Rigsby ◽  
D. R. Thomas ◽  
B. D. Gardner

Physical training in the form of long-term nonexhaustive daily exercise was studied as a means of regulating fatty acid biosynthesis. Male rats were required to swim for periods up to 90 min/day. The exercise was carried out 6 days/wk for approximately 11 wk. Hepatic fatty acid biosynthesis and acetyl-CoA carboxylase [acetyl-CoA: CO2 ligase (EC 6.4.1.2)] activities were compared with nonexercised rats. At the end of the training period the exercised rats had a lower rate of fatty acid biosynthesis activity and a lower rate of acetyl-CoA carboxylase activity. The difference in acetyl-CoA carboxylase activity was due to a change in maximal velocity with no significant change in the Michaelis constant for acetyl-CoA. Untrained rats were subjected to a single bout of exercise. They also exhibited lower rates of fatty acid biosynthesis and acetyl-CoA carboxylase activities compared with nonexercised rats. However, the lower rates of these enzyme activities were sustained longer in the physically trained rats compared with the exercised untrained rats after the cessation of exercise. These results implicate acetyl-CoA carboxylase as a control site in the regulation of hepatic fatty acid biosynthesis by both physical training and acute exercise in rats. Possible inhibitory mechanisms are discussed.


1986 ◽  
Vol 14 (3) ◽  
pp. 559-562 ◽  
Author(s):  
MICHAEL R. MUNDAY ◽  
TIMOTHY A. J. HAYSTEAD ◽  
ROSS HOLLAND ◽  
DAVID A. CARLING ◽  
D. GRAHAME HARDIE

Author(s):  
Xiaoyu Cai ◽  
Marcio de Queiroz ◽  
Glen Meades ◽  
Grover Waldrop

The enzyme acetyl-CoA carboxylase catalyzes the first committed step in fatty acid synthesis in all organisms. The E. coli form of the carboxyltransferase subunit was recently found to regulate its own activity and expression by binding its own mRNA. By binding acetyl-CoA or the mRNA encoding its own subunits, Carboxyltransferase is able to sense the metabolic state of the cell and attenuate its own translation and enzymatic activity using a negative feedback mechanism. In this paper, this network of interactions is modeled mathematically using mass action kinetics. Numerical simulations of the model show agreement with experimental results.


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