SCIENCE AT THE EDGE SEMINAR

QB/GEDD

Friday, April 25 at 11:30am

Room 1400 Biomedical and Physical Sciences Bldg.

Refreshments at 11:15

L. Aravind

National Center for Biotechnology

National Institute of Health

From Biological Conflicts to Biochemical Innovation

Biological conflicts are the mainstay of life. These include a number of distinct types of conflicts featuring remarkable biochemical systems such as: 1) intra-genomic conflicts, e.g. toxin-antitoxin and restriction-modification systems; 2) inter-genomic conflicts, e.g. the CRISPR/Cas system involved in restricting invasive genomes like bacteriophages; 3) intra-specific conflicts, e.g. polymorphic toxin systems; 4) inter-specific conflicts, e.g. antibiotics and toxins deployed by organisms against competitors or hosts, and mechanisms of immunity against them. My lab has been involved in the discovery of such systems using comparative genomics and protein sequence/structure analysis. This has led to the elucidation of novel biochemistry and understanding of previous unknown mechanistic details of proteins. I will illustrate this using examples relating to eukaryotic chromatin, nucleic acid modification, nucleic acids polymerases, toxin and immunity systems.  Highlights would include our discovery of major contributions from catalytic domains of bacterial toxin systems to the origin of mutagenic enzymes for immune receptor diversification, RNA processing and signaling enzymes. Similarly, I would also touch upon contributions of bacterial antibiotic/siderophore synthesis systems and intra-genomic and intra-cellular selfish elements (e.g., restriction-modification, mobile elements and lysogenic phages) in the emergence of chromatin remodeling/modifying enzymes and RNA-based regulation. I will present the concept that biological conflict systems served as evolutionary "nurseries" for innovations in the protein world, which were delivered to eukaryotes via lateral gene flow to spur key evolutionary innovations.