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Office: CHEM 475A
Phone: 410-455-2510
Professional Interests
Research Group
Richard Karpel
Professor and Acting Chair
B.A. Queens College, CUNY 1965; Ph.D. Brandeis University 1970
Structure of gene 32 protein core domain bound to a single-stranded oligonucleotide
Typical stopped-flow trace of gene 32 protein *I truncate binding poly(dT)
Structure-function studies on single-stranded nucleic acid binding proteins

I am predominantly interested in structure-function studies on single-strand specific nucleic acid binding proteins (also known as helix-destabilizing proteins). As a class, the binding proteins have a wide range of biological roles, yet they share a number of biochemical commonalities. These include homologous functional domains, regions responsible for nucleic acid interaction, binding cooperativity, and interaction with other proteins.

The binding proteins under current investigation include bacteriophage T4 gene 32 protein, involved in DNA replication, recombination and repair, and the nucleocapsid (NC) proteins of retroviruses, which have a role in viral RNA packaging and replication, and act as “chaperones”, facilitators of nucleic acid conformational change. Gene 32 protein, historically one of the first of this class of proteins to be characterized, continues to provide us with fascinating insights.

Having identified an amino acid sequence (the 'LAST' Motif) involved in both protein-nucleic acid and protein-protein interaction, we are particularly concerned with understanding the relationship of these two binding activities, and in further delineating the structural basis of the protein's binding cooperativity and nucleic acid binding surface, the kinetic control of helix-destabilizing activity, and the protein’s interaction with other T4 replication, repair, and recombination proteins.  In our structure-function studies we employ a broad spectrum of experimental approaches, including biophysical, protein chemical, and molecular biological methodologies.

We recently initiated nucleic acid binding studies on crotamine, a toxic, basic protein that is a major component of the venom of the South American rattlesnake.  Crotamine has been shown to be a cell-penetrating protein that localizes in the chromosome.  It has potential use as a drug-delivery vehicle.  At present nothing is known about the DNA- and RNA-interactive properties of crotamine, and we present several approaches toward quantifying these interactions.