John E. Cronan
YOU?
Author Swipe
Switching the strict substrate specificities of the β-ketoacyl-acyl carrier protein synthases, FabH and BioZ Open
The β-ketoacyl-acyl carrier protein (ACP) synthases are pivotal elongation enzymes that catalyze the condensation of acyl-CoA or acyl-ACP with malonyl-ACP to produce β-ketoacyl-ACP. Among these, the homologous enzymes FabH (β-ketoacyl-ACP …
Two putative Enterococcus faecalis fabG genes do not encode β-ketoacyl-acyl carrier protein reductases Open
Enterococcus faecalis encodes three putative Escherichia coli β-ketoacyl-acyl carrier protein (ACP) reductases (FabG). The fabG1 gene is located within the operon that encodes most of the fatty acid synthesis genes, while the putative fabG…
Enterococcus faecalis requires unsaturated fatty acids to overcome toxicity of environmental saturated fatty acids Open
Enterococcus faecalis synthesizes phospholipids from either de novo synthesized or exogenous fatty acids. However, environmental saturated fatty acids are toxic to E. faecalis . The mechanism of toxicity is unknown. We report that saturate…
Approaches to Study Proteins Encoded by Essential Genes Open
Although the phenotypes and functions of nonessential proteins can be studied by deletion of their coding sequences (both gene copies in diploid organisms), essential genes cannot be deleted unless loss of the encoded protein can be bypass…
Defining the <i>Enterococcus faecalis</i> Fatty Acid Kinase System of Exogeneous Fatty Acid Utilization Open
Phospholipid synthesis in Firmicute bacteria differs markedly from that of the paradigm Escherichia coli pathway in that acyl phosphates are a key intermediate. Acyl phosphates are required for the first acylation step of the phospholipid …
The puzzle of two tandem acyl-CoA ligases of <i>Pseudomonas putida</i> F1 Open
The Pseudomonas putida F1 genome and those of many other pseudomonads contain two tandem genes encoding acyl-CoA ligases Pput_1340 ( fadD1 ) and Pput_1339 ( fadD2 ) with Pput_1339 ( fadD2 ) being the upstream gene. The fadD designation was…
The Enteric Bacterium <i>Enterococcus faecalis</i> Elongates and Incorporates Exogenous Short and Medium Chain Fatty Acids Into Membrane Lipids Open
Enterococcus faecalis incorporates and elongates exogeneous short‐ and medium‐chain fatty acids to chains sufficiently long to enter membrane phospholipid synthesis. The acids are activated by the E. faecalis fatty acid kinase (FakAB) syst…
Lipoic acid attachment to proteins: stimulating new developments Open
SUMMARY Lipoic acid-modified proteins are essential for central metabolism and pathogenesis. In recent years, the Escherichia coli and Bacillus subtilis lipoyl assembly pathways have been modified and extended to archaea and diverse eukary…
Biotin protein ligase as you like it: Either extraordinarily specific or promiscuous protein biotinylation Open
Biotin (vitamin H or B7) is a coenzyme essential for all forms of life. Biotin has biological activity only when covalently attached to a few key metabolic enzyme proteins. Most organisms have only one attachment enzyme, biotin protein lig…
Suppressor mutants demonstrate the metabolic plasticity of unsaturated fatty acid synthesis in Pseudomonas aeruginosa PAO1 Open
Pseudomonas aeruginosa PAO1 has two aerobic pathways for synthesis of unsaturated fatty acids (UFAs), DesA and DesB plus the oxygen independent FabAB pathway. The DesA desaturase acts on saturated acyl chains of membrane phospholipid bilay…
Two neglected but valuable genetic tools for <i>Escherichia coli</i> and other bacteria: In vivo cosmid packaging and inducible plasmid replication Open
In physiology and synthetic biology, it can be advantageous to introduce a gene into a naive bacterial host under conditions in which all cells receive the gene and remain fully functional. This cannot be done by the usual chemical transfo…
Growth of <i>Enterococcus faecalis</i> ∆ <i>plsX</i> strains is restored by increased saturated fatty acid synthesis Open
The Enterococcus faecalis acyl-acyl carrier protein (ACP) phosphate acyltransferase PlsX plays an important role in phospholipid synthesis and exogenous fatty acid incorporation. Loss of plsX almost completely blocks growth by decreasing d…
How an overlooked gene in coenzyme a synthesis solved an enzyme mechanism predicament Open
Coenzyme A (CoA) is an essential cofactor throughout biology. The first committed step in the CoA synthetic pathway is synthesis of β‐alanine from aspartate. In Escherichia coli and Salmonella enterica panD encodes the responsible enzyme, …
Divergent unsaturated fatty acid synthesis in two highly related model pseudomonads Open
The genomes of the best‐studied pseudomonads , Pseudomonas aeruginosa and Pseudomonas putida , which share 85% of the predicted coding regions, contain a fabA fabB operon (demonstrated in P. aeruginosa , putative in P. putida ). The enzyme…
Unsaturated fatty acid synthesis in <i>Enterococcus faecalis</i> requires a specific <span>enoyl‐ACP</span> reductase Open
The Enterococcus faecalis genome contains two enoyl‐ACP reductases genes, fabK and fabI , which encode proteins having very different structures. Enoyl‐ACP reductase catalyzes the last step of the elongation cycle of type II fatty acid syn…
The Two Acyl Carrier Proteins of Enterococcus faecalis Have Nonredundant Functions Open
Enterococcus faecalis , as well as related species, has two genes— acpA and acpB —encoding putative acyl carrier proteins (ACPs). It has been assumed that AcpA is essential for fatty acid synthesis whereas AcpB is involved utilization of e…
View article: Loss of β-Ketoacyl Acyl Carrier Protein Synthase III Activity Restores Multidrug-Resistant Escherichia coli Sensitivity to Previously Ineffective Antibiotics
Loss of β-Ketoacyl Acyl Carrier Protein Synthase III Activity Restores Multidrug-Resistant Escherichia coli Sensitivity to Previously Ineffective Antibiotics Open
Gram-negative pathogens are a major concern for global public health due to increasing rates of antibiotic resistance and the lack of new drugs. A major contributing factor toward antibiotic resistance in Gram-negative bacteria is their fo…
The Enterococcus faecalis FabT Transcription Factor Regulates Fatty Acid Biosynthesis in Response to Exogeneous Fatty Acids Open
The phospholipid acyl chains of Enterococcus faecalis can be derived either by de novo synthesis or by incorporation of exogenous fatty acids through the fatty acid kinase complex (Fak)-phosphate acyltransferase (PlsX) pathway. Exogenous f…
Advances in the Structural Biology, Mechanism, and Physiology of Cyclopropane Fatty Acid Modifications of Bacterial Membranes Open
Cyclopropane fatty acid (CFA) synthase catalyzes a remarkable reaction. The cis double bonds of unsaturated fatty acyl chains of phospholipid bilayers are converted to cyclopropane rings by transfer of a methylene moiety from S-adenosyl-L-…
View article: Loss of β-ketoacyl acyl carrier protein synthase III activity restores multidrug-resistant <i>Escherichia coli</i> sensitivity to previously ineffective antibiotics
Loss of β-ketoacyl acyl carrier protein synthase III activity restores multidrug-resistant <i>Escherichia coli</i> sensitivity to previously ineffective antibiotics Open
Antibiotic resistance is one of the most prominent threats to modern medicine. In the latest World Health Organization list of bacterial pathogens that urgently require new antibiotics, nine out of 12 are Gram-negative, with four being of …
A conserved and seemingly redundant <i>Escherichia coli</i> biotin biosynthesis gene expressed only during anaerobic growth Open
Biotin is an essential metabolic cofactor and de novo biotin biosynthetic pathways are widespread in microorganisms and plants. Biotin synthetic genes are generally found clustered into bio operons to facilitate tight regulation since biot…
The Classical, Yet Controversial, First Enzyme of Lipid Synthesis: Escherichia coli Acetyl-CoA Carboxylase Open
Escherichia coli acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of the malonyl-CoA, the building block of fatty acid synthesis, is the paradigm bacterial ACC. Many reports on the structures and stoichiometry of the four…
A division of labor between two biotin protein ligase homologs Open
Group I biotin protein ligases (BPLs) catalyze the covalent attachment of biotin to its cognate acceptor proteins. In contrast, Group II BPLs have an additional N‐terminal DNA‐binding domain and function not only in biotinylation but also …
Temperature regulation of membrane composition in the Firmicute, <span> <i>Enterococcus faecalis</i> </span> , parallels that of <span> <i>Escherichia coli</i> </span> Open
Summary Both Enterococcus faecalis and Escherichia coli can undergo abrupt temperature transitions in nature. E . coli changes the composition of its phospholipid acyl chains in response to shifts growth temperature. This is mediated by a …
Biotin, a universal and essential cofactor: synthesis, ligation and regulation Open
Biotin is a covalently attached enzyme cofactor required for intermediary metabolism in all three domains of life. Several important human pathogens (e.g. Mycobacterium tuberculosis) require biotin synthesis for pathogenesis. Humans lack a…
Escherichia coli FabG 3-ketoacyl-ACP reductase proteins lacking the assigned catalytic triad residues are active enzymes Open
The FabG 3-ketoacyl-acyl carrier protein (ACP) reductase of Escherichia coli has long been thought to be a classical member of the short-chain alcohol dehydrogenase/reductase (SDR) family. FabG catalyzes the essential 3-ketoacyl-ACP reduct…