Mark E. Bier, Associate Research Professor

Carnegie Mellon University

Center for Molecular Analysis, Room 860

Mellon Institute

4400 Fifth Ave.

Pittsburgh, PA 15213

Ph.D. Purdue University

Physical/Analytical Biochemistry

Our research is focused on the development of new mass spectrometry (MS) instrumentation and methods to improve the analysis of biomolecules including nano-sized particles.  Past research activities have examined the protein modification of CDC25 by anti-cancer drugs, the reactivity of hexamethylene diisocyanate with human serum albumin and the identification of a new protein isolated from a chicken eye.
 

A current objective of our research is to characterize biomacromolecules and biomacromolecular complexes.  In this pursuit, we are developing a heavy ion mass spectrometer (NSF funded).  This new instrument will also allow us to study the limitations of MS at high m/z and high molecular weight.  Electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) will produce the heavy ions while a unique heavy ion detector will sense them. The new detector technology has a tremendous advantage over conventional detectors because it is, theoretically, 100% efficient at high mass.   This research is expected to impact molecular biology, virology and polymer chemistry.  We expect to be able to analyze ribosomal particles, virus particles, DNA/RNA protein complexes and nano-sized synthetic particles.   To date, we have recorded the highest molecular weight polymer ever seen by MALDI TOF MS at 2.2 Mega-Da and, remarkably, a virus particle at 13 Mega-Da.

Another focus of our research is to develop a micro-reactor for real-time analysis of various molecular complexes and processes including protein folding, enzyme digestion, protein/small molecule adduction, protein complexes, DNA melting, caged ion systems and synthetic polymers.   Our device has been coupled to our ESI ion trap mass spectrometer and we intend to coupled it to our heavy ion mass spectrometer discussed above.  Our preliminary results have shown that hen lysozyme can be unfolded and monitored using our reactor and this protein shows two conformations by this method. We have also characterized enzyme digestion reactions of both proteins and oligonucleotides.

Environmental Chemistry

The objective of our environmental interests is to monitor low levels of semi-volatile molecules in water or air using electrospray ionization membrane introduction MS (MIMS) probes.   Our MIMS probes have shown detection limit in the ppb to ppt range.