Investigation of lanthipeptides and their applications

Eslami, Sara Miriam

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https://hdl.handle.net/2142/124624 Copy

Description

Title

Investigation of lanthipeptides and their applications

Author(s)

Eslami, Sara Miriam

Issue Date

2024-02-22

Director of Research (if dissertation) or Advisor (if thesis)

van der Donk, Wilfred A

Doctoral Committee Chair(s)

van der Donk, Wilfred A

Committee Member(s)

• Metcalf, William W
• Zhao, Huimin
• Manesis, Anastasia C

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• lanthipeptide
• ribosomally synthesized and post-translationally modified peptide

Abstract

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a subset of natural products defined by a genetically encoded precursor peptide that is post-translationally modified by class-defining enzymes. While bioactivity-guided screening remains a popular tool for identifying antimicrobial RiPPs, advances in bioinformatic technologies have allowed for the rapid expansion of novel RiPPs encoded within growing genome databases. Lanthipeptides are a subset of RiPPs characterized by the dehydration of Ser and Thr amino acids to form dehydroalanine (Dha) and dehydrobutyrine (Dhb) residues, respectively; free thiols of Cys residues then react with these dehydrated amino acids in a Michael-type addition to form (methyl)lanthionine rings yielding a stable, multi-cyclic peptide. Lanthipeptides may have diverse activities e.g. anti-bacterial, anti-fungal, anti-viral, and antiallodynic activities. Chapter 2 focuses on the bioinformatics-informed detection and purification of a two-component class II lanthipeptide termed birimositide from the producing organism Streptomyces rimosus subsp. rimosus. The proposed structure of birimositide is illustrated as well as its synergistic antibacterial activity. Chapter 3 demonstrates the utility of bioinformatic tools in generating a high-throughput catalogue of bioactive RiPPs. This effort, termed FAST-RiPPs (fully automated, scalable high-throughput RiPPs), enabled the discovery of novel class III lanthipeptides from undermined phyla. Unique proteases not previously reported in class III biosynthesis are described as well as bioactivity of a class III lanthipeptide from Bacillus amyloliquefaciens. Finally, chapter 4 describes the construction of a lanthipeptide expression system in adherent and suspension mammalian cell lines. The helical, class II lanthipeptide cytolysin L (CylLL), CylLL variants, and the class II lanthipeptide haloduracin A2 were expressed fully modified in mammalian cells. Successful targeting of the lanthipeptides to the nucleus is also shown. Subsequent utilization of this expression system is further suggested for screening of a CylLL library to identify helical protein-protein interaction inhibitors.

Graduation Semester

2024-05

Type of Resource

Thesis

Copyright and License Information

© 2024 Sara M. Eslami

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