scholarly journals ZmaR, a Novel and Widespread Antibiotic Resistance Determinant That Acetylates Zwittermicin A

1999 ◽  
Vol 181 (17) ◽  
pp. 5455-5460 ◽  
Author(s):  
Elizabeth A. Stohl ◽  
Sean F. Brady ◽  
Jon Clardy ◽  
Jo Handelsman

ABSTRACT ZmaR is a resistance determinant of unusual abundance in the environment and confers on gram-positive and gram-negative bacteria resistance to zwittermicin A, a novel broad-spectrum antibiotic produced by species of Bacillus. The ZmaR protein has no sequence similarity to proteins of known function; thus, the purpose of the present study was to determine the function of ZmaR in vitro. Cell extracts of E. coli containing zmaR inactivated zwittermicin A by covalent modification. Chemical analysis of inactivated zwittermicin A by 1H NMR, 13C NMR, and high- and low-resolution mass spectrometry demonstrated that the inactivated zwittermicin A was acetylated. Purified ZmaR protein inactivated zwittermicin A, and biochemical assays for acetyltransferase activity with [14C]acetyl coenzyme A demonstrated that ZmaR catalyzes the acetylation of zwittermicin A with acetyl coenzyme A as a donor group, suggesting that ZmaR may constitute a new class of acetyltransferases. Our results allow us to assign a biochemical function to a resistance protein that has no sequence similarity to proteins of known function, contributing fundamental knowledge to the fields of antibiotic resistance and protein function.

2009 ◽  
Vol 191 (6) ◽  
pp. 1749-1755 ◽  
Author(s):  
Jeffrey G. Gardner ◽  
Jorge C. Escalante-Semerena

ABSTRACT This report provides in vivo evidence for the posttranslational control of the acetyl coenzyme A (Ac-CoA) synthetase (AcsA) enzyme of Bacillus subtilis by the acuA and acuC gene products. In addition, both in vivo and in vitro data presented support the conclusion that the yhdZ gene of B. subtilis encodes a NAD+-dependent protein deacetylase homologous to the yeast Sir2 protein (also known as sirtuin). On the basis of this new information, a change in gene nomenclature, from yhdZ to srtN (for sirtuin), is proposed to reflect the activity associated with the YdhZ protein. In vivo control of B. subtilis AcsA function required the combined activities of AcuC and SrtN. Inactivation of acuC or srtN resulted in slower growth and cell yield under low-acetate conditions than those of the wild-type strain, and the acuC srtN strain grew under low-acetate conditions as poorly as the acsA strain. Our interpretation of the latter result was that both deacetylases (AcuC and SrtN) are needed to maintain AcsA as active (i.e., deacetylated) so the cell can grow with low concentrations of acetate. Growth of an acuA acuC srtN strain on acetate was improved over that of the acuA + acuC srtN strain, indicating that the AcuA acetyltransferase enzyme modifies (i.e., inactivates) AcsA in vivo, a result consistent with previously reported in vitro evidence that AcsA is a substrate of AcuA.


2007 ◽  
Vol 189 (22) ◽  
pp. 8250-8256 ◽  
Author(s):  
Keiichi Uchino ◽  
Terumi Saito ◽  
Birgit Gebauer ◽  
Dieter Jendrossek

ABSTRACTPoly(3-hydroxybutyrate) (PHB) granules isolated in native form (nPHB granules) fromRalstonia eutrophacatalyzed formation of PHB from14C-labeled acetyl coenzyme A (CoA) in the presence of NADPH and concomitantly released CoA, revealing that PHB biosynthetic proteins (acetoacetyl-CoA thiolase, acetoacetyl-CoA reductase, and PHB synthase) are present and active in isolated nPHB granules in vitro. nPHB granules also catalyzed thiolytic cleavage of PHB in the presence of added CoA, resulting in synthesis of 3-hydroxybutyryl-CoA (3HB-CoA) from PHB. Synthesis of 3HB-CoA was also shown by incubation of artificial (protein-free) PHB with CoA and PhaZa1, confirming that PhaZa1 is a PHB depolymerase catalyzing the thiolysis reaction. Acetyl-CoA was the major product detectable after incubation of nPHB granules in the presence of NAD+, indicating that downstream mobilizing enzyme activities were also present and active in isolated nPHB granules. We propose that intracellular concentrations of key metabolites (CoA, acetyl-CoA, 3HB-CoA, NAD+/NADH) determine whether a cell accumulates or degrades PHB. Since the degradation product of PHB is 3HB-CoA, the cells do not waste energy by synthesis and degradation of PHB. Thus, our results explain the frequent finding of simultaneous synthesis and breakdown of PHB.


2008 ◽  
Vol 190 (14) ◽  
pp. 5132-5136 ◽  
Author(s):  
Jeffrey G. Gardner ◽  
Jorge C. Escalante-Semerena

ABSTRACT The acuABC genes of Bacillus subtilis comprise a putative posttranslational modification system. The AcuA protein is a member of the Gcn5-related N-acetyltransferase (GNAT) superfamily, the AcuC protein is a class I histone deacetylase, and the role of the AcuB protein is not known. AcuA controls the activity of acetyl coenzyme A synthetase (AcsA; EC 6.2.1.1) in this bacterium by acetylating residue Lys549. Here we report the kinetic analysis of wild-type and variant AcuA proteins. We contrived a genetic scheme for the identification of AcuA residues critical for activity. Changes at residues H177 and G187 completely inactivated AcuA and led to its rapid turnover. Changes at residues R42 and T169 were less severe. In vitro assay conditions were optimized, and an effective means of inactivating the enzyme was found. The basic kinetic parameters of wild-type and variant AcuA proteins were obtained and compared to those of eukaryotic GNATs. Insights into how the isolated mutations may exert their deleterious effect were investigated by using the crystal structure of an AcuA homolog.


2002 ◽  
Vol 184 (3) ◽  
pp. 636-644 ◽  
Author(s):  
Meike Musfeldt ◽  
Peter Schönheit

ABSTRACT Acetyl coenzyme A (CoA) synthetase (ADP forming) (ACD) represents a novel enzyme of acetate formation and energy conservation (acetyl-CoA + ADP + Pi ⇌ acetate + ATP + CoA) in Archaea and eukaryotic protists. The only characterized ACD in archaea, two isoenzymes from the hyperthermophile Pyrococcus furiosus, constitute 145-kDa heterotetramers (α2, β2). The coding genes for the α and β subunits are located at different sites in the P. furiosus chromosome. Based on significant sequence similarity of the P. furiosus genes, five open reading frames (ORFs) encoding putative ACD were identified in the genome of the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus and one ORF was identified in the hyperthermophilic methanogen Methanococcus jannaschii. The ORFs constitute fusions of the homologous P. furiosus genes encoding the α and β subunits. Two ORFs, AF1211 and AF1938, of A. fulgidus and ORF MJ0590 of M. jannaschii were cloned and functionally overexpressed in Escherichia coli. The purified recombinant proteins were characterized as distinctive isoenzymes of ACD with different substrate specificities. In contrast to the Pyrococcus ACD, the ACDs of Archaeoglobus and Methanococcus constitute homodimers of about 140 kDa composed of two identical 70-kDa subunits, which represent fusions of the homologous P. furiosus α and β subunits in an αβ (AF1211 and MJ0590) or βα (AF1938) orientation. The data indicate that A. fulgidus and M. jannaschii contains a novel type of ADP-forming acetyl-CoA synthetase in Archaea, in which the subunit polypeptides and their coding genes are fused.


1999 ◽  
Vol 181 (4) ◽  
pp. 1088-1098 ◽  
Author(s):  
Castor Menendez ◽  
Zsuzsa Bauer ◽  
Harald Huber ◽  
Nasser Gad’on ◽  
Karl-Otto Stetter ◽  
...  

ABSTRACT The pathway of autotrophic CO2 fixation was studied in the phototrophic bacterium Chloroflexus aurantiacus and in the aerobic thermoacidophilic archaeon Metallosphaera sedula. In both organisms, none of the key enzymes of the reductive pentose phosphate cycle, the reductive citric acid cycle, and the reductive acetyl coenzyme A (acetyl-CoA) pathway were detectable. However, cells contained the biotin-dependent acetyl-CoA carboxylase and propionyl-CoA carboxylase as well as phosphoenolpyruvate carboxylase. The specific enzyme activities of the carboxylases were high enough to explain the autotrophic growth rate via the 3-hydroxypropionate cycle. Extracts catalyzed the CO2-, MgATP-, and NADPH-dependent conversion of acetyl-CoA to 3-hydroxypropionate via malonyl-CoA and the conversion of this intermediate to succinate via propionyl-CoA. The labelled intermediates were detected in vitro with either 14CO2 or [14C]acetyl-CoA as precursor. These reactions are part of the 3-hydroxypropionate cycle, the autotrophic pathway proposed forC. aurantiacus. The investigation was extended to the autotrophic archaea Sulfolobus metallicus andAcidianus infernus, which showed acetyl-CoA and propionyl-CoA carboxylase activities in extracts of autotrophically grown cells. Acetyl-CoA carboxylase activity is unexpected in archaea since they do not contain fatty acids in their membranes. These aerobic archaea, as well as C. aurantiacus, were screened for biotin-containing proteins by the avidin-peroxidase test. They contained large amounts of a small biotin-carrying protein, which is most likely part of the acetyl-CoA and propionyl-CoA carboxylases. Other archaea reported to use one of the other known autotrophic pathways lacked such small biotin-containing proteins. These findings suggest that the aerobic autotrophic archaea M. sedula,S. metallicus, and A. infernus use a yet-to-be-defined 3-hydroxypropionate cycle for their autotrophic growth. Acetyl-CoA carboxylase and propionyl-CoA carboxylase are proposed to be the main CO2 fixation enzymes, and phosphoenolpyruvate carboxylase may have an anaplerotic function. The results also provide further support for the occurrence of the 3-hydroxypropionate cycle in C. aurantiacus.


2019 ◽  
Vol 11 (510) ◽  
pp. eaas9917 ◽  
Author(s):  
Joost Schalkwijk ◽  
Erik L. Allman ◽  
Patrick A. M. Jansen ◽  
Laura E. de Vries ◽  
Julie M. J. Verhoef ◽  
...  

Malaria eradication is critically dependent on new therapeutics that target resistant Plasmodium parasites and block transmission of the disease. Here, we report that pantothenamide bioisosteres were active against blood-stage Plasmodium falciparum parasites and also blocked transmission of sexual stages to the mosquito vector. These compounds were resistant to degradation by serum pantetheinases, showed favorable pharmacokinetic properties, and cleared parasites in a humanized mouse model of P. falciparum infection. Metabolomics revealed that coenzyme A biosynthetic enzymes converted pantothenamides into coenzyme A analogs that interfered with parasite acetyl–coenzyme A anabolism. Resistant parasites generated in vitro showed mutations in acetyl–coenzyme A synthetase and acyl–coenzyme A synthetase 11. Introduction and reversion of these mutations in P. falciparum using CRISPR-Cas9 gene editing confirmed the roles of these enzymes in the sensitivity of the malaria parasites to pantothenamides. These pantothenamide compounds with a new mode of action may have potential as drugs against malaria parasites.


1983 ◽  
Vol 37 (1) ◽  
pp. 81-88 ◽  
Author(s):  
R. L. Prior ◽  
S. B. Smith ◽  
B. D. Schanbacher ◽  
H. J. Mersmann

ABSTRACTTwenty bull calves were assigned to one of four treatment groups: 1) intact bulls; 2) intact bulls implanted with oestradiol dipropionate; 3) steers, and 4) steers implanted with oestradiol dipropionate. Subcutaneous adipose tissue was obtained by biopsy 5 months after implantation. Experimental treatment did not alter (P > 0·05) mean adipose cell volume, diameter or cell number per g adipose tissue. Soluble protein content of adipose cells from bulls was increased by implantation, but not in steers. In vitro rates of fatty acid synthesis were higher in oestrogen-implanted cattle compared with nonimplanted cattle when expressed per g adipose tissue, but not when expressed per cell. Maximal activities of the lipogenic-related enzymes, acetyl coenzyme A carboxylase, adenosine triphosphate-citrate lyase, aconitate hydratase and NADP-isocitrate dehydrogenase were higher in implanted compared with nonimplanted cattle when the activities were expressed per g tissue and acetyl coenzyme A carboxylase and aconitase were also higher when expressed per adipose cell. Bulls and steers had the same basal and stimulated lipolytic rates and implantation of oestradiol dipropionate had no effect on either basal or stimulated lipolytic rate. In this experiment, the oestrogenic implant appeared to have a stimulatory effect on in vitro estimates of lipogenesis.


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