Structure and Stability of Hyperstable Proteins: Glycolytic Enzymes From Hyperthermophilic Bacterium Thermotoga Maritima

Abstract

Publisher Summary This chapter discusses structure and stability of hyperstable proteins. It compares selected proteins from a hyperthermophilic micro-organism with corresponding homologs from mesophilic sources. Apart from the wild-type proteins and mutants with varying intrinsic stabilities, mechanisms of stabilization are discussed, based on model systems such as subdomains, domains, and subunits. The solution of the stability problem has biological and technological implications: biological, because of the evolutionary aspects of adaptive response reactions to physiological stress; and technological, because the molecular mechanisms of thermal adaptation might be applicable in producing engineered thermostable proteins in connection with bioreactors and biosensors. This chapter focuses mainly on a representative hyperthermophilic bacterium, Thermotoga maritime, which has optimized its cellular functions to a maximum growth temperature of about 90°C. In all cases reported for T. mantima enzymes, the proteins were found to be intrinsically stable up to temperatures beyond the optimum growth temperature of the bacterium. Covalent modifications that are reported as an additional mechanism of protein stabilization seem to be absent in T. muritima.