people
|Faculty
|Michael Trakselis
 |
Michael Trakselis Department of Chemistry |
*****Postdoctoral Applications Accepted*****
Projects in the Trakselis laboratory center on understanding the molecular mechanisms of DNA replication and exploiting this knowledge for cancer therapeutics, biotechnology, and nanoscale applications. We utilize a model archaeal DNA replication system which shares significant homology to that of higher eukaryotes but is amenable to in vitro biochemistry experiments. This allows us to draw parallels between different domains of life using simpler replication systems. In this aim, we utilize molecular biology, biochemistry, genetics, cell biology and biophysical methods to probe this area of research.
In vitro DNA Replication in Archaea
One of the hallmarks of DNA replication in archaea is that their replication machinery seems to be more closely related in sequence and function to eukaryotes than prokaryotes. Even though archaea seem to posses most of the homologous replication factors found in eukaryotes, the organization of the complexes are much simpler, in most cases requiring fewer polypeptides to perform similar functions. This allows for a less complicated experimental approach to studying DNA replication in a system where the conclusions can be directly compared to those from higher eukaryotes. We are currently investigating the elongation stage of DNA replication in the crenarachaeon, Sulfolobus solfataricus, to better understand the role of the three B-type DNA polymerases found in this organism.
Characterizing MCM8/9 in higher eukaryotes
The mini chromosome maintenance proteins (MCMs) have been proposed to be the replicative helicase and may play some role in the organization of DNA during S phase. Although much effort has been aimed at understanding the role of MCM2-7 in DNA replication initiation, MCM8 and MCM9, paralogs of MCM2, have also recently been implicated in replication elongation. These proteins are not found in lower eukaryotes such as yeast or C. elegans; so, its function has evolved only in higher eukaryotes. We are currently examining the role of MCM8/9 in human cells with regards to DNA replication and repair. We are trying to determine the function of these proteins through identifying functional interactions with other replication/repair factors within the cell as well as perform in vitro biochemical characterizations.
Nanoscale and biotechnology applications of replication proteins
Through my research on DNA replication, I have seen how biology has evolved to use toroids to processively direct catalysis on DNA. I intend to investigate the possibility of directing polymer chemistry using protein toroids with an attached catalyst. An organic catalyst can be attached via an engineered cysteine residue within proteins to construct a bio-hybrid system that has the potential to carry out processive catalysis on polymers threads which have similar properties to DNA. We are examining various biological protein toroids from DNA replication and repair systems as the scaffold for this catalyst. Other projects include exploiting the thermostability of archaeal enzymes for industrial and biotechnology catalysts.
Awards
Royal Society Postdoctoral Fellowship, 2003; PSU Alumni Association Research Award, 2002; Henry and Catherine Dalalian Graduate Student Research Award, 2002; Homer F. Braddock Graduate Research Fellowship, 2001; Nellie and Oscar L. Roberts Graduate Fellowship, 1998.
Selected Publications
"Assembly of the Bacteriophage T4 Primosome: Single Molecule and Ensemble Studies," Zhang, Z, Spiering, M.M., Trakselis, M.A., Ishmael, F.T., Xi, J., Benkovic, S.J., and Hammes, G.G., PNAS, 2005, 102, 3254-3259
"Identification of Protein-Protein Interactions Using Novel Crosslinking Reagents," Trakselis, M.A., Alley, S.C., and Ishmael, F.T., Bioconjugate Techniques, 2005, 16, 741-750
"Organization of the Archaeal MCM Complex on DNA and Implications for a Helicase Mechanism," McGeoch, A.T., Trakselis, M.A., Laskey, R.A., and Bell, S.D., Nat Struc. Mol. Biol., 2005, 12, 756-762
"The Trimeric Bacteriophage T4 Clamp is Open at One Interface in Solution," Millar, D., Trakselis, M.A., and Benkovic, S.J., Biochemistry, 2004, 43, 12723-7
"Dissociative Properties of the Proteins within the Bacteriophage T4 Replisome," Trakselis, M.A., Roccasecca, R., Yang, J., Valentine, A., and Benkovic, S.J., J. Biol. Chem., 2003, 278, 49839-49
"The Application of a Minicircle Substrate in the Study of the Coordinated T4 DNA Replication," Yang, J., Trakselis, M.A., Roccasecca, R., and Benkovic, S.J., J. Biol. Chem., 2003, 278, 49828-38
"Protein-Protein Interactions in the Bacteriophage T4 Replisome: The Leading Strand Holoenzyme is Physically Linked to the Lagging Strand Holoenzyme and Primosome," Ishmael, F.T. Trakselis, M.A., and Benkovic, S.J., J. Biol. Chem, 2003, 278, 3145-3152
"Examination of the Role of the Clamp-Loader and ATP Hydrolysis in the Formation of the Bacteriophage T4 Polymerase Holoenzyme," Trakselis, M.A., Berdis, A.J., Benkovic, S.J., J. Mol. Biol., 2003, 326, 435-451
"Building a Replisome Solution Structure by Elucidation of Protein-Protein Interactions in the Bacteriophage T4 DNA Polymerase Holoenzyme," Alley, S.C., Trakselis, M.A., Mayer, M.U., Ishmael, F.T., Jones, A.D., Benkovic, S.J., J. Biol. Chem., 2001, 276, 39340-49
"Creating a Dynamic Picture of the Sliding Clamp During T4 DNA Polymerase Holoenzyme Assembly Using Fluorescence Resonance Energy Transfer," Trakselis, M.A., Alley, S.C., Abel-Santos, E., Benkovic, S.J., PNAS, 2001, 98, 8368-75