Professor of Chemistry
Ph.D.| University of South Hampton
Postdoctoral Fellowship | University of Washington, 1987-1989
One of our major research areas is centered around microorganisms that produce secondary metabolites or natural products. These compounds find widespread use including antibiotics, immunosuppressants, anticancer agents, and antiparasitic agents. The carbon skeleton core of many of these compounds are produced by polyketide synthases (PKSs). We are studying these complex fascinating biosynthetic processes at both the genetic and enzymatic level. A combination of genetic techniques, including molecular breeding and in vivo recombination, are being used to generate engineered microorganisms in which the natural biosynthetic process of interest has been diverted, in some cases through the use of catalytically efficient hybrid PKSs. In combination with chemoenzymatic approaches and precursor-directed mutasynthesis we are producing a wide range of new natural products with a variety of biological activities.
Currently we are interested in the phoslactomycin (PLMs) and fostriecin (compounds with antitumor and antifungal activity), hygromycin A and pikromycin (antibacterial activity) and prodiginines (compounds with interesting immunosuppressant, antimalarial and antitumor activities). We have been able to generate a library of more than 50 new phoslactomycins and are evaluating their biological activities. We have also discovered that the prodiginines are orally effective in the treatment of malaria in mice.
We also study the primary metabolic pathways which provide the necessary precursors for assembling natural products. We have shown that manipulation of these processes affect the ratio and yields of natural product in a fermentation process. Currently we are both deciphering the importance of competing precursor pathways in mutagenized industrial strains under fermentation conditions which produce high titers of the natural product. We are also utilizing these strains as super hosts for heterologous expression of natural product biosynthetic processes where fermentation yields from the native microorganism are a limiting factor.
Our second area of research interests is the pathway of plant and bacterial fatty acid biosynthesis, catalyzed by type II fatty acid synthases (FASs). The unique features of this pathway, and of enzyme specific to this process have attracted considerable interest as both targets for both antibiotic development and biofuel production in bacteria and transgenic plants. 3-Ketoacyl ACP synthase III (KASIII) initiates fatty acid biosynthesis in this process by catalyzing a condensation between an acyl CoA and a malonyl ACP substrate. We are actively investigating different KASIII enzymes from Staphylococci aureus, Escherichia coli, and Mycobacterium tuberculosis (the organism that causes tuberculosis) and Plasmodial falciparum (the parasite responsible for malaria). We are using mutagenesis, molecular modeling, kinetic analyses and X-ray diffraction to probe the mechanism and varying substrate specificities of these enzymes. We have crystallized and solved the structure of the M. tuberculosis KASIII, believed to play a critical role in initiating mycolate biosynthesis in this pathogenic microorganism. We have designed and synthesized several series of selective synthetic KASIII inhibitors and are using techniques such as molecular modeling and X-ray crystallography with a long term goal of developing these into a new generation of antimalarial, antibacterial and antituberculosis drugs.
- Mo, S. J., Kim, B. S. and Reynolds, K. A. : Production of novel alkylprodiginines in Streptomyces coelicolor by replacement of the 3-ketoacyl ACP synthase III initiation enzyme (RedP), Chem. Biol., 12 , 191-200, 2005.
- Musayev, F, Sachdeva, S., Scarsdale, J.N., Reynolds, K. A. and Wright, H. T Crystal Structure of a Substrate Complex of Mycobacterium Tuberculosis 3-Ketoacyl-Acyl Carrier Protein Synthase III (FabH) with Lauroyl-Coenzyme-A. J. Mol. Biol., 346, 1313-21, 2005.
- Li, Y, Florova, G and Reynolds, K. A. Alteration of the fatty acid profile of Streptomyces coelicolor by replacement of the initiation enzyme 3-ketoacyl ACP synthase III (FabH), J. Bacteriol, 187, 3795-9, 2005.
- Das Choudhuri, S., Ayers, S., Soine, W. H., and Reynolds, K. A. A pH-stability study of phoslactomycin B and analysis of the acid and base degradation products. J. Antibiotics, 58, 573-582, 2005.
- Ghatge, M., and Reynolds, K. A. The plmS2 -encoded cytochrome P450 monooxygenase mediates hydroxylation of phoslactomycin B in Streptomyces sp. HK803, J. Bacteriol., 187, 7970-6, 2005.
- Akopiants, K., Florova, G., Li, C., and Reynolds, K. A. Multiple pathways for acetate assimilation in Streptomyces cinnamonnensis. J. Indus. Microbiol. Biotechnol., 33, 141-50, 2006.
- Li, C., Akopiants, K. and Reynolds, K. A. Identification and disruptional analysis of the Streptomyces cinnamonensis msdA gene, encoding methylmalonic acid semialdehyde dehydrogenase, J. Indus. Microbiol. Biotechnol., 33, 75-83, 2006.
- Ghatge, M, Palaniappan, N, Das Choudhuri, S, and Reynolds, K. A., Genetic manipulation of the biosynthetic process leading to phoslactomycins, potent PP2A inhibitors, J. Indus. Microbiol. Biotechnol., 33:589-99, 2006.
- Palaniappan, N., Ayers,S., Gupta, S., Habib E.-S, and Reynolds, K. A., Production of hygromycin A analogues in Streptomyces hygroscopicus NRRL 2388 through identification and manipulation of the biosynthetic gene cluster. Chem. Biol., 13, 753-64, 2006.
- Ghatge, M, Palaniappan, N, Das Choudhuri, S, and Reynolds, K. A., Genetic manipulation of the biosynthetic process leading to phoslactomycins, potent PP2A inhibitors, J. Indus. Microbiol. Biotechnol., 33, 589-99, 2006.
- Alhamadsheh, M.M., Waters, N.C., Huddler, D.P., Kresihamn-Deitrick, D., Florova, G., and Reynolds, K. A. Synthesis and biological evaluation of thiazolidine-2-one 1,1-dioxide as inhibitors of Escherichia coli beta-ketoacyl-ACP-synthase III (FabH). Bioorganic Med. Chem. Lett., Dec 1: 17, 879-83, 2007
- Palaniappan, N, and Reynolds, K. A. "Hygromycin A Biosynthesis" Chapter 2 in "ACS Symposium Series 955 Polyketides Biosynthesis, Biological Activity and Genetic Engineering" Ed Rimando A.M and Baerson S.R., Publisher American Chemical Society 2007.
- Alhamadsheh, M. M., Palaniappan, N., DasChouduri, S., and Reynolds KA. Modular Polyketide Synthases and cis-Double Bond Formation: Establishment of Activated cis-3-Cyclohexylpropenoic Acid as the Diketide Intermediate in Phoslactomycin Biosynthesis. J. Amer. Chem. Soc. 129, 1910-1, 2007.
- Alhamadsheh, M.M.,Musayev, F.,Komissarov, A. A., Sachdeva,S. Wright, H. T.,Scarsdale, J. N., Florova,G., Reynolds, K. A. Alkyl-CoA disulfides as inhibitors and mechanistic probes for FabH enzymes, Chem. Biol., 14, 513-524 2007.
- Wright, H. T, and Reynolds, K. A. "Antibacterial targets in fatty acid biosynthesis" Current Op. Microbiol., 10, 447-453, 2007
- S. Sadcheva, Musayev, Alhamadheh, M.M., Scardsdale, J. N., Wright, T. N., and Reynolds, K. A., "Probing reactivity and substrate specificity of both subunits of the dimeric Mycobacterium tuberculosis using acyl-CoA disulfide inhibitors and acyl-CoA substrates" Bioorg. Chem. 36, 85-90, 2008
- Mo. S., Sydor, P.K., Corre, C., Alhamadsheh, M.M., Stanley, A.E., Haynes, S.W., Song, K.A. and Challis, G. L. "Elucidation of the Streptomyces coelicolor pathway to 2-undecylpyrrole, a key intermediate in undecylprodiginine and streptorubin B biosynthesis" Chem. Biol., 15, 137-48, 2008
- Sadcheva, S., and Reynolds, K. A. "Mycobacterium tuberculosis beta-ketoacyl acyl carrier protein synthase III (mtFabH) assay: principles and method". Methods Mol Med., 142, 205-13, 2008
- Sachdeva S, Musayev FN, Alhamadsheh MM, Scarsdale JN, Wright HT, Reynolds KA. "Separate entrance and exit portals for ligand traffic in Mycobacterium tuberculosis FabH", Chem Biol. 15, 402-12. 2008
- Turos, E., Revell, K. D., Ramaraju, P., Gergereres, D. A. Grennhalgh, K., Young, A., Dickey, S., Lim, D., Nalini, S., Alhamadsheh, M.M. and Reynolds, K. A. "Unsymmetric aryl-alkyl disulfide growth inhibitors of methicillin-resisitant Staphylococcus aureus and Bacillus anthracis" Bioorg and Med. Chem., in press, 2008.
- Dothe, V and Reynolds,Kevin A., "Antibiotic resistance: An O-phosphotransferase catalyzes phosphorylation and inactivation of hygromycin A in the producing organism, Streptomyces hygroscopicus," Antimicro. Chemother. In press, 2008.
- Palaniappan, N, Alhamadsheh, M.M, and Reynolds, K. A., "cis-Δ2,3-Double Bond of Phoslactomycins Is Generated by a Post-PKS Tailoring Enzyme, J. Amer. Chem. Soc, 130, 12236-12237, 2008.
- Alhamadsheh, M.M, Waters, N.C., Sadcheva, S., Lee, P., and Reynolds, K. A.", "Synthesis and biological evaluation of novel sulfonyl-napthalene-1,4-diols as FabH inhibitors" Bioorg and Med. Chem., 18, 6402-5, 2008.>/li>
- Gupta S, Lakshmanan V, Kim BS, Fecik R, Reynolds KA Generation of novel pikromycin antibiotic products through mutasynthesis. Chembiochem., 9, 1609-16, 2008.
- Buchholz, T.J., Geders, T.W. Bartley, III, F.E., Reynolds, K.A., Smith, J.L and Sherman, D. H. Structural Basis for Binding Specificity Between Subclasses of Modular Polyketide Synthase Docking Domains, Chemical Biology, 4, 41-52, 2009
- Ghatge, M.S., Palaniappan, N, Alhamadsheh, M. M and Reynolds, K. A., Phoslactomycins biosynthesis: Identification and characterization an 18-O-acyltransferase, and application in chemoenzymatic synthesis of selected natural and non-natural bioactive derivatives, Appl. Environ. Microbiol., 75: 3469-76, 2009;
- Eusta'quio, A.S., McGlinchey, R.P., Liu, Y., Hazzard C., Beer, L.L , Florova, G., Alhamadsheh, M.M., Lechner, A., Kale, A.J., Kobayashi, Y, Reynolds, K. A., Moore, B. S.,Biosynthesis of the salinosporamide A polyketide synthase substrate chloroethylmalonyl-coenzyme A from S-adenosyl-L-methionine, Proc. Natl. Acad. Sci., USA, early edition 2009.
- Liu, Y., Hazzard, C., Eustaquio, A.S., Reynolds, K.A. and Moore, B.S. Biosynthesis of Salinosporamides from α,β-Unsaturated Fatty Acids: Implications for Extending Polyketide Synthase Diversity, J. Amer. Chem. Soc., July 14th, Web-based release, 2009.
- Li, C., Hazzard, C, Florova, G., and Reynolds, K. A. High titer production of tetracenomycins by heterologous expression of the pathway in a Streptomyces cinnamonensis industrial monensin producer strain, Metabolic Engineering, in press, 2009.