Chemistry and Chemical Biology ETDs

Publication Date

Summer 7-29-2025

Abstract

Abstract:

Graspetides are a family of Ribosomally synthesized and Post-translationally modified Peptide (RiPP) natural products named for their ATP Grasp Macrocyclases. We identified several Graspetide Biosynthetic Gene Clusters containing common double glycine cleavage motifs and attempted characterization of the mature Graspetides. One of the resulting peptides, Thatisin, has a topology with two interlocking macrolactones installed by a single ATP Grasp Ligase named ThtC. Here we use single and double point mutations to observe the impact or variation on the installation of these macrocycles. Alanine scan mutagenesis is used to assess leader peptide residues in the precursor peptide ThtA to determine the recognition sequence while ThtA core peptide mutants test the substrate tolerance allotted by ThtC when its catalytic mechanism is impacted by alterations in steric effect or heteroatoms.

Project Sponsors

Dr. Mark Walker and the National Institute of Health

Language

English

Keywords

Graspetide, RiPPs, Peptide, ATP Grasp Ligase, Alanine Scan, Mutational Analysis

Document Type

Dissertation

Degree Name

Chemistry and Chemical Biology

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Dr. Mark Walker

Second Committee Member

Dr. William Garver

Third Committee Member

Dr. Anisha Shakya

Fourth Committee Member

Dr. Christopher Johnson

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