Structural Insights into Thioether Bond Formation in the Biosynthesis of Sactipeptides

Sactipeptides are ribosomally synthesized peptides that contain a characteristic thioether bridge (sactionine bond) that is installed posttranslationally and is absolutely required for their antibiotic activity. Sactipeptide biosynthesis requires a unique family of radical SAM enzymes, which contain multiple [4Fe-4S] clusters, to form the requisite thioether bridge between a cysteine and the α-carbon of an opposing amino acid through radical-based chemistry. Here we present the structure of the sactionine bond-forming enzyme CteB, from Clostridium thermocellum ATCC 27405, with both SAM and an N-terminal fragment of its peptidyl-substrate at 2.04 Å resolution. CteB has the (β/α)6-TIM barrel fold that is characteristic of radical SAM enzymes, as well as a C-terminal SPASM domain that contains two auxiliary [4Fe-4S] clusters. Importantly, one [4Fe-4S] cluster in the SPASM domain exhibits an open coordination site in absence of peptide substrate, which is coordinated by a peptidyl-cysteine residue in the bound state. The crystal structure of CteB also reveals an accessory N-terminal domain that has high structural similarity to a recently discovered motif present in several enzymes that act on ribosomally synthesized and post-translationally modified peptides (RiPPs), known as a RiPP precursor peptide recognition element (RRE). This crystal structure is the first of a sactionine bond forming enzyme and sheds light on structures and mechanisms of other members of this class such as AlbA or ThnB.

Medienart:

E-Artikel

Erscheinungsjahr:

2017

Erschienen:

2017

Enthalten in:

Zur Gesamtaufnahme - volume:139

Enthalten in:

Journal of the American Chemical Society - 139(2017), 34 vom: 30. Aug., Seite 11734-11744

Sprache:

Englisch

Beteiligte Personen:

Grove, Tyler L [VerfasserIn]
Himes, Paul M [VerfasserIn]
Hwang, Sungwon [VerfasserIn]
Yumerefendi, Hayretin [VerfasserIn]
Bonanno, Jeffrey B [VerfasserIn]
Kuhlman, Brian [VerfasserIn]
Almo, Steven C [VerfasserIn]
Bowers, Albert A [VerfasserIn]

Links:

Volltext

Themen:

7LP2MPO46S
Iron-Sulfur Proteins
Journal Article
Peptides
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
S-Adenosylmethionine
Sulfides

Anmerkungen:

Date Completed 11.06.2018

Date Revised 06.10.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1021/jacs.7b01283

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM273799614