Ph.D. - Australian National University, 1985

Associate Professor

Center for Advanced Research in Biotechnology

9600 Gudelsky Dr.

Rockville, MD 20850 USA

Phone: (301)-738-6221

Email: john@magpie.carb.nist.gov

Research Specialty: NMR Spectroscopy.

Protein G:
Protein G is a multi-domain component of the cell wall of some streptococcal species that binds to immunoglobulin G (IgG) at the constant Fc region. The IgG-binding function is contained in globular domains of 56 amino acids, referred to as GB. Our present interests include (1) determination of the tertiary structure of GB in solution using a combination of 2DNMR, distance geometry, and backcalculation methods; (2) analysis of the IgG-binding site and conformation of bound GB using 1H-15N 2D and 3DNMR experiments (eg. HMQC, NOESY-HMQC); (3) use of GB as a model to study protein folding and stability using amide exchange/protection methods. Engineered mutants obtained in Dr. Bryan's laboratory at CARB are also being used in the above studies to gain insights into the relationships between structure and stability/binding affinity.

Nucleic Acid Structure and Dynamics:
We are particularly interested in the solution structure and dynamics of RNA bulged loops. These ubiquitous motifs play an important role in RNA-protein interactions (eg. the HIV-TAR:tat complex) and RNA folding. Information about the amplitude and time-scale of internal motion in the base, furanose ring, and backbone moieties can be obtained using solid state NMR techniques on site-specifically deuterated oligonucleotides. This methodology was originally developed on DNA oligomers and is presently being extended to RNA systems. Initial RNA results indicate substantial differences in backbone mobility between RNA and DNA duplexes.