Roberto De Guzman

Roberto De Guzman
  • Professor
  • Principal Investigator, IRACDA

Contact Info

Haworth Hall
1200 Sunnyside Avenue
Lawrence, KS 66045


Postdoctoral Researcher, Scripps Research Institute, San Diego, CA
Ph.D., University of Maryland, Baltimore County, Baltimore County, Maryland


Structures and molecular interactions of virulence proteins

Our research is aimed at understanding the structures and molecular interactions of virulence proteins that are required by pathogens to cause infectious diseases in humans.  The relevance of our research in public health is in the area of antibiotic resistance.  In particular, we study nanoinjectors of the bacterial type III secretion system.  These are nanoscale syringes assembled by pathogens from many proteins, and used to inject virulence proteins directly into human cells to cause infectious diseases.   We seek to understand how nanoinjectors are assembled and how small molecules can disrupt this assembly.

Nanoinjectors are absolutely essential in the pathogenesis of many bacteria.  For example, annually, Shigella is estimated to cause up to 1.1 million deaths worldwide, including 350,000 deaths in young children.  There are recurring Salmonella outbreaks in our food supply.  There are still sporadic outbreaks of Yersinia pestis, which caused the Black Death in Europe during medieval times that altered the trajectory of human history.  Among cystic fibrosis patients, secondary lung infection by Pseudomonas aeruginosa is the major cause of death. All pathogens that require nanoinjectors for infectivity have developed resistance to current antibiotics.

There is therefore a need to develop new antibiotics against these pathogens.  Bacterial nanoinjectors are exposed on the bacterial surface and are present only among pathogens, thus, disrupting their assembly is an attractive approach for developing novel anti-infectives.  This approach requires a detailed understanding of the structures and molecular interactions involved in the assembly of nanoinjectors.  We use NMR and biophysical methods to determine the structures, protein-protein interactions, and small molecule-protein interactions of nanoinjectors.