Differential protein splicing of salt‐dependent inteins from Haloquadratum walsbyi

Abstract

Protein splicing is a self‐catalyzed, post‐translational process in which an intervening polypeptide sequence, or an intein, catalyzes its removal from two flanking polypeptide sequences, or exteins, as well as the ligation of the exteins. We are interested in the splicing capabilities of two inteins that interrupt the cdc21 protein from Haloquadratum walsbyi (Hwa). Hwa is a halophilic archaeon found in high salt environments such as the Red Sea. For this reason, we hypothesize that protein splicing may be salt dependent. We are interested in studying the splicing capabilities of both inteins separately and when expressed as part of the same protein. One intein, Cdc21a, does not splice on overexpression in E. coli, but can be induced to splice in vitro on incubation with 2.5 M sodium chloride at 28°. The other intein, Cdc21d, splices in vivo, and can be induced to splice further with higher concentrations of salt. When expressed in the same precursor fusion protein, the inteins continue to show differential activity conditional on salt concentration, leading to alternative spliced products. We hypothesize that this differential protein splicing is due to the folding of the protein under different salt conditions.Support or Funding InformationThis work was supported by the National Science Foundation (grants MCB‐1244089), the Dreyfus Foundation (KVM), and Diane D. Brink P12 to the Alumni/Parent Summer Research Scholarship Fund. ALThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.