Báo cáo Y học: A b-lysine adenylating enzyme and a b-lysine binding protein involved in poly b-lysine chain assembly in nourseothricin synthesis in Streptomyces noursei

A ẞ-lysine adenylating enzyme and a ẞ-lysine binding protein involved in poly ẞ-lysine chain assembly in Nourseothricin synthesis in Streptomyces noursei

Author(s): Nicolas Grammel, Kvitka Pankevych, Julia Demydchuk, Klaus Lambrecht, Hans-Peter Saluz, Ullrich Keller, Hans Krügel

Field: Biochemistry and Molecular Biology

Abstract: This study investigates the biosynthesis of nourseothricins, a class of nucleoside peptides characterized by a poly-β-lysine chain. Researchers identified and characterized two key enzymes from *Streptomyces noursei*: NpsA, a β-lysine activating enzyme that performs adenylation, and NpsB, a β-lysine binding protein. NpsA functions as a standalone adenylation domain, distinct from typical nonribosomal peptide synthetases (NRPS). NpsB comprises a peptidyl carrier protein (PCP) domain and a domain resembling epimerization (E) domains of NRPS. The findings suggest that an iteratively operating NRPS-like module, involving NpsA and NpsB, is responsible for the assembly of the poly-β-lysine chain in nourseothricin synthesis. The research also explores the substrate specificity of NpsA, indicating a high degree of selectivity for β-lysine.

Detailed Table of Contents:

• Introduction to Nourseothricins and their Biosynthesis
• Identification and Characterization of NpsA (β-lysine activating enzyme)
• Identification and Characterization of NpsB (β-lysine binding protein)
• Gene Cloning and Sequencing of npsA and npsB
• Enzyme Assays and Substrate Specificity
• Discussion of the Poly-β-lysine Assembly Mechanism
• Materials and Methods
• Results
• References