Mechanistic studies of lanthipeptide biosynthetic enzymes and discovery of novel lanthipeptides

Desormeaux, Emily K.

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https://hdl.handle.net/2142/124653 Copy

Description

Title

Mechanistic studies of lanthipeptide biosynthetic enzymes and discovery of novel lanthipeptides

Author(s)

Desormeaux, Emily K.

Issue Date

2024-04-26

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)

• Mitchell, Douglas A
• Mehta, Angad P
• 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
• lanthionine
• enzyme kinetics
• ProcM
• Roseocin

Abstract

Natural products and their derivatives have been a significant source of therapeutic compounds, making up two-thirds of all drugs approved between 1981 and 2019. Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a diverse class of natural products capable of exhibiting diverse biological activities. Lanthipeptides make up a large portion of known RiPPs, characterized by thioether crosslinks. Lanthipeptides contain diverse ring patterns that can be installed by five different classes of enzymes, some of which exhibit great substrate tolerance that can be exploited for bioengineering purposes. Novel lanthipeptides have been identified using both library generation and bioinformatic guided discovery. ProcM is a class II lanthipeptide synthetase that has been utilized for the generation of several lanthipeptide libraries because of its remarkable substrate tolerance. These lanthipeptide libraries have been met with varying degrees of success due in large part to the inability to accurately predict the final ring pattern produced by ProcM on the basis of substrate sequence. Chapter 2 describes several methods as possible means to predict the installed ring patterns as well as ProcM cyclization mechanism studies. The ability to accurately make these predictions would allow for better generation of libraries and the design of lanthipeptides with a defined three-dimensional structure. Mechanistic studies of the class I lanthipeptide biosynthetic enzyme, PciB, were also performed to determine the method of substrate recognition in Chapter 3. This biosynthetic gene cluster was identified via bioinformatic guided discovery and was selected in part because the genetically encoded precursor peptide lacked the canonical FNLD recognition motif. Another example of utilizing bioinformatic methods for identification of novel lanthipeptides is the discovery of roseocin. Roseocin is a two-component lanthipeptide with reported bioactivity against several clinically relevant pathogens. Bioinformatic analysis of the roseocin peptides suggests both contain novel ring patterns compared to other two-component lanthipeptides. Chapter 4 will focus on the structural characterization of roseocin via advanced Marfey’s and NMR analysis.

Graduation Semester

2024-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2024 Emily Desormeaux

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