Topic:
Proteins Designed to Order

Abstract:
Understanding the structure/function relationships of proteins is fundamental in elucidating the remarkable catalytic performance of enzymes. New high-throughput screening tools are necessary for protein engineering efforts, and directed evolution has emerged as an efficient method to investigate protein function and to design proteins with improved properties. The bottleneck of directed evolution is oftentimes the screen or selection. Surface display of proteins on Bacillus subtilis spores will be developed as a tool for high-throughput screening. Spore display offers advantages over more commonly utilized microbe cell-surface display systems, which include gram-negative bacteria, phage, and yeast. For instance, protein-folding problems are avoided that are associated with the recombinant polypeptide crossing membranes.  In addition, spores tolerate many physical/chemical extremes. Therefore, the displayed proteins are “preimmobilized” on the inherently inert spore surface. Immobilized proteins have several advantages when used in industrial processes. The protein stability is increased and separations are simplified. Finally, immobilized proteins can be used in a wide array of simple device applications and configurations. 

The goal is to demonstrate that spores are a suitable vehicle for high-throughput screening for improved protein properties.  In addition, protein structure/function will be investigated.  The copper containing enzyme CotA, a laccase from B. subtilis, will be used as a model system.  The factors that tune redox potential will be elucidated. CotA has a low redox potential, and it will be evolved for increased redox potential. Finally, the factors that contribute to substrate specificity will be considered. CotA is a “generalist”, an enzyme with broad substrate specificity, and it will be engineered to function as a “specialist”, an enzyme with narrowed substrate specificity.  Important laccase applications include pulp bleaching and delignification, degradation of polycyclic aromatic hydrocarbons, and biofuel cells. 

Seminar Series Coordinators:
Dr. Zeyuan Qiu       zeyuan.qiu@njit.edu             973-596-5357
Dr. Sergiu Gorun    sergiu.m.gorun@njit.edu       973-569-6595