The Variable Salt Dependence of Mini‐Inteins from Haloquadratum walsbyi

Abstract

Protein splicing is a post‐translational modification by which a segment of protein, known as an intein, self‐catalyzes its excision from the protein (exteins) while simultaneously ligating the two flanking exteins. Inteins can be found in many types of archaebacteria, including halophiles, which thrive in environments with high salt concentrations. Previous results have shown that mini inteins of Haloquadratum walsbyi, such as those interrupting the cdc21 protein, require high concentrations of salt to splice. One intein that interrupts the DNA Gyrase B splices in E. coli, whereas similar inteins have required high salt incubation in vitro for splicing. The Hwa cdc21a, cdc21c, and PolIIb inteins were likely present in the most recent halophile ancestor as they are monophyletic within the halobacteria, the PolIIa and cdc21b inteins are polyphyletic, and the GyrB intein is likely related to inteins from bacteria. It is hypothesized that the GyrB intein has more recently invaded the halobacteria, therefore making the intein less stable to unfolding in the presence of salt when compared to earlier invading inteins, which many have adapted to high salt environments and are dependent on high salt concentrations for activity.Support or Funding InformationThis work was supported by the National Science Foundation (grants MCB‐1244089 and MCB‐1517138 to KVM) and the Dreyfus Foundation (KVM).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.