College Honors Program

Salty Enzymes: Protein Splicing Dependence on Salt Concentrations

Date of Creation

5-1-2022

Document Type

Campus Access Only

Department

Biology

First Advisor

Kenneth Mills

Abstract

Extremophiles are microorganisms capable of living in Earth’s most extreme environments. Halophiles are a subset of extremophiles that require high salt concentrations (up to 5 M NaCl) to survive. The high salt concentration allows for their proteins to fold correctly and therefore function properly. Some archaeal proteins contain inteins that undergo a reaction called protein splicing. Protein splicing is a posttranslational modification in which the intein, an intervening polypeptide sequence, is self-catalytically removed from two terminal extein sequences. The exteins are ligated together to form a mature, functioning protein. Halobacterium salinarum is an extremophile with a DNA polymerase II enzyme that contains an intein. Despite a high level of sequence conservation of this enzyme’s intein between H. salinarum and other non-halophilic organisms, only H. salinarum’s enzyme requires high salt concentrations to splice. Investigating the biochemistry behind these organisms will help us better understand how life functions at Earth’s extreme conditions, their evolutionary history, and potentially extraterrestrial life on Mars if discovered.

Comments

Reader: Robert Bellin

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