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John E. Cronan

Profile picture for John E. Cronan

Contact Information

601 S Goodwin Ave
Urbana, IL 61801

Alumni Professor of Microbiology
Professor of Microbiology
Professor of Biochemistry

Research Interests

Enzymology, Genetics, Membrane Biology, Microbial Physiology, Regulation of Gene Expression

Research Description

Genetic approaches to regulation of lipid metabolism; synthesis and attachment of biotin and lipoic acid

My laboratory works in two main areas-regulation of lipid metabolism and synthesis and attachment of fatty acid related enzyme cofactors. In both areas, the organism studied is Escherichia coli due to its sophisticated genetics and simple lipid composition. However we also study a variety of gram positive bacteria.

We have studied mechanisms that regulate the composition of the membrane phospholipids of E. coli and are currently concerned how this organism regulates lipid synthesis such that it is neither "fat nor lean." Although, E. coli is the paradigm for bacterial lipid synthesis there are bacteria that are missing genes that are in essential for E. coli growth.  We are in process of figuring out which proteins these bacteria use in place of those used by E. coli.  This has practical consequences because bacterial fatty acid synthesis is the target of several newly developed antibiotics.  We have found that two key coenzymes, how lipoic acid and biotin, found in all three domains of life require the fatty acid synthetic pathway for their synthesis.   We have determined how E. coli makes these coenzymes and are now expanding into the pathways found in other bacteria.

research image from Conan lab










B.A. (Biology), California State University, 1965
Ph.D. (Molecular Biology), University of California, Irvine, 1968
Postdoctoral (Biochemistry), Washington University School of Medicine, 1968-1970

Awards and Honors

Member, National Academy of Sciences
Fellow, American Academy of Microbiology
University Scholar
Microbiology Alumni Endowed Professorship

Additional Campus Affiliations

Highlighted Publications

Representative Publications

Hu, Z and Cronan, J. E(2020) The primary step of biotin synthesis in mycobacteria. Proc. Natl Acad, Sci U S A 117:23794-23801. PMID 32900960. PMC7519262

Hu, Y. and Cronan, J. E(2020) α-Proteobacteria synthesize biotin precursor pimeloyl-ACP using the BioZ 3-ketoacyl-ACP synthase and lysine catabolism. Nature Commun;11::5598. PMCID: PMC7645780.

Hu,, Z., Ma,, J, Tong,, W., Zhu, L, Wang,, H. and J E Cronan (2021) Escherichia coli FabG 3-ketoacyl-ACP reductase proteins lacking the assigned catalytic triad residues are active enzymes. J. Biol Chem Feb 2;:000365. PMC7973133.

Dong, H and Cronan, J. E. (2021) Temperature regulation of membrane composition in the firmicute, Enterococcus faecalis, parallels that of Escherichia coli. Environ Microbiol 2021 May;23(5):2683-2691. doi: 10.1111/1462-2920.15512. Epub 2021 Apr 18.PMID: 33830615

Song, X. Henke, S. K. and Cronan, J. E. (2021) A division of labor between two biotin protein ligase homologs. Mol Microbiol May 24. doi: 10.1111/mmi.14761.

Huijuan Dong, H. Ma, J., Chen, Q., Chen, B, Liang, L., Liao, Y., Song, Y., Wang, H. and Cronan, J. E. (2021) A cryptic long.-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway. J. Biol. Chem. Jun 25:100920. doi: 10.1016/j.jbc.2021.100920.

Cronan, J. E. (2020) Progress in the enzymology of the mitochondrial diseases of lipoic acid requiring enzymes. Front. Genet. 21;11:510. PMCID: PMC7253636

Cronan, J. E. (2021) The Escherichia coli FadR transcription factor: Too much of a good thing? Mol. Microbial Dec 7. doi: 10.1111/mmi.14663. Online ahead of print.

Sirithanakorn,, C. and Cronan, J. E. (2021) Biotin, an essential cofactor: synthesis, ligation, regulation and role in virulence. FEMS Microbiol Rev. Jan 11:fuab003. doi: 10.1093/femsre/fuab003. Online ahead of print. PMC7973133.

Cronan, J. E. (2021) The Classical, Yet Controversial, First Enzyme of Lipid Synthesis: Escherichia coli Acetyl-CoA Carboxylase. Microbial. Mol. Biol. Rev. un 16:e0003221. doi: 10.1128/MMBR.00032-21.

Recent Publications

Cronan, J. E. (2024). Biotin protein ligase as you like it: Either extraordinarily specific or promiscuous protein biotinylation. Proteins: Structure, Function and Bioinformatics, 92(4), 435-448.

Cronan, J. E. (2024). Unsaturated fatty acid synthesis in bacteria: Mechanisms and regulation of canonical and remarkably noncanonical pathways. Biochimie, 218, 137-151.

Guo, Q., Zhong, C., Dong, H., Cronan, J. E., & Wang, H. (2024). Diversity in fatty acid elongation enzymes: The FabB long-chain β-ketoacyl-ACP synthase I initiates fatty acid synthesis in Pseudomonas putida F1. Journal of Biological Chemistry, 300(2), Article 105600.

Cronan, J. E. (2023). How an overlooked gene in coenzyme a synthesis solved an enzyme mechanism predicament. Molecular Microbiology, 119(6), 687-694.

Cronan, J. E. (2023). The acyl carrier proteins of lipid synthesis are busy having other affairs. Biochemical Journal, 480(12), 855-873.

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