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| Michael Benedik earned a B.A. with Honors in 1976 from the University of Chicago. There he began his research career studying mobile genetic elements conferring drug resistance in bacteria with Dr. James Shapiro. He attended graduate school at Stanford University earning his Ph.D. in 1982. His graduate studies focused on gene regulation in bacteriophage lambda and the decision between lysis and lysogeny. In 1982 he joined the DNAX Research Institute where he was a staff scientist working on antibody expression and production in bacteria. In 1984 Dr. Benedik joined Texas A&M University, first in the Department of Medical Biochemistry and Genetics and then in Biology as an Assistant Professor. In 1989 he moved to the University of Houston where he eventually earned the rank of Professor and was Vice-Chair of the Department of Biology and Biochemistry. In 2004 Dr. Benedik returned to Texas A&M University as a Professor in the Department of Biology. Dr. Benedik has taught a variety of courses in the areas of microbiology, molecular biology and genetics. |
Michael Benedik 3258 TAMU Office: Lab: Fax: 979-845-2891 |
| Bacterial Molecular Genetics and Biotechnology
My laboratory studies basic biological problems using molecular genetic methods with simple microbial systems. Additionally we are developing novel microbial approaches for biotechnological applications. The following outline the projects currently underway in the laboratory. Protein import and export in bacteria. The movement of proteins across cellular membranes involve a complicated set of reactions necessitated by the thermodynamic difficulty of passing a soluble aqueous protein across the hydrophobic barrier that is a biological membrane. Despite this, cells have evolved precise and efficient systems by which they secrete proteins outwards from their site of synthesis into other compartments or into the extracellular milieu. This is not a reversible process in normal biochemical systems, yet some proteins are known to enter into cells from the outside. My lab has worked for a number of years on the problem of protein export, utilizing the extracellular nuclease of S. marcescens as a model protein. However we have recently begun a new project on protein import. Bacteriocidal colicins are such proteins that are taken up by E. coli. Most colicins are pore forming proteins that act by insertion into the cytoplasmic membrane. However the enzymatic bacteriocins kill by the action of an enzymatic domain in the cytoplasm. The Colicin E2 protein is a 62 kDa protein that carries as its lethal agent a potent endodeoxyribonucleolytic domain (DNase), which, when imported into a bacterial cell kills by degrading the genome. In this new project I aim to investigate the molecular machinery, the energetic requirements, and the protein-protein interactions that comprise the import reaction of E2 into a cell. Biotechnology/Bioremediation - Cyanide The aim of this project is better enzymes for degrading cyanide in waste streams and contaminated sites. The industrial uses of cyanide have resulted in contamination at many sites, especially the water and soil of metal plating plants and as the result of ore extraction in mining operations. Especially in light of recent highly-publicized incidents of cyanide contamination (e.g., in Houston-area plating facilities as well as the recent cyanide release in Eastern Europe) there is a need to develop lower-cost, efficient methods to detoxify these sites. Cyanide is a common constituent of biological systems and is actually produced by a variety of organisms, especially plants. Due to the toxicity of cyanide, nature has evolved numerous biochemical pathways for its conversion to innocuous byproducts. There is previous work on biodegradation of cyanide, either by enzymes or metabolically-active whole cells, using a variety of different pathways. The most interesting for our project are those cyanide-degrading enzymes which can function without the need for active cellular metabolism, and can be used under conditions which would kill microorganisms. We hope to apply modern molecular biology to improve the cost, stability, and metal-tolerance of cyanidases, enzymes which convert cyanide directly to formate and ammonia. These end products are vastly less toxic than cyanide, and they can also be directly metabolized by indigenous microorganisms to cell mass, CO2, and water. Like other enzymes, cyanidases are capable of scavenging and destroying their substrate (i.e., cyanide) down to extremely low levels (< 0.01 ppm). Cyanidases have already been applied to cyanide removal, but the commercial technology is relatively old, and has not taken advantage of: (1) the ability to overexpress enzyme activities in alternative hosts, (2) opportunities for functional improvement by protein engineering, and (3) the discovery and cloning (by others in the literature) of new forms of this enzyme with potentially superior properties. |
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Woodward JD, Weber BW, Scheffer MP, Benedik MJ, Hoenger A, Sewell BT. (2008) Helical structure of unidirectionally shadowed metal replicas of cyanide hydratase from Gloeocercospora sorghi. J Struct Biol. 161:111-119. Strych U, Davlieva M, Longtin JP, Murphy EL, Im H, Benedik MJ, Krause KL. (2007) Purification and preliminary crystallization of alanine racemase from Streptococcus pneumoniae. BMC Microbiol. 7(1):40 Sewell, B.T., R.N. Thuku, X. Zhang, and M. J. Benedik. (2005). Oligomeric structure of nitrilases, effect of mutating interfacial residues on activity. Ann. N.Y. Acad Sci. 1056:153-159. Jandhyala, D. M., R.C. Willson B. T. Sewell and M.J. Benedik. (2005) Comparison of cyanide-degrading nitrilases. Applied Microbiology and Biotechnology 68:327-335. LeMagueres P, Im H, Dvorak A, Strych U, Benedik M, Krause KL. (2003) Crystal Structure at 1.45 Å Resolution of Alanine Racemase from a Pathogenic Bacterium, Pseudomonas aeruginosa, Contains Both Internal and External Aldimine Forms. Biochemistry. 42:14752-14761. Gibbs, P.R., Riddle, R., L. Marchal, M.J. Benedik and R.C. Willson (2003) Purification and characterization of 2'aminobiphenyl-2,3-Diol 1,2-dioxygenase from Pseudomonas sp. LD2. Protein Expression and Purification 32:35-43. Sewell, T., P. Meyers, M. Berman, D. Jandhyala, and M.J. Benedik. (2003) The Cyanide Degrading Nitrilase from Pseudomonas stutzeri AK61 is a Twofold Symmetric, 14-Subunit Spiral. Structure 11:1413-22. Jandhyala, D., M. Berman, P. Meyers, T. Sewell, R.C. Willson and M.J. Benedik. (2003) CynD, the cyanide dihydratase from Bacillus pumilus: Gene cloning and structural studies. Applied and Environmental Microbiology .69:4794-4805. Samartzidou, H, Mehrazin, M., Xu, Z., Benedik, M. J. and A.H. Delcour. (2003) Cadaverine Inhibition of Porin Plays a Role in Cell Survival at Acidic pH. Journal of Bacteriology. 185:13-19. Kim, M.G. U. Strych, K. Krause, M. Benedik, and H. Kohn. (2003) N(2)-Substituted D,L-Cycloserine Derivatives: Synthesis and Evaluation as Alanine Racemase Inhibitors. The Journal of Antibiotics 56:160-168. Riddle, R., P.R. Gibbs, R.C. Willson and M.J. Benedik (2003). Purification and Properties of 2-hydroxy-6-oxo-6-(2'-aminophenyl)hexa-2,4-dienoic acid Hydrolase Involved with Microbial Degradation of Carbazole. Protein Expression and Purification. 28:182-189. Riddle, R., P.R. Gibbs, R.C. Willson and M.J. Benedik (2003) Dioxygenase modification of carbazole for enhanced petroleum processing. Journal of Industrial Microbiology and Biotechnology. 30:6-12. |
