8P50

Photorhabdus luminescens Makes caterpillars floppy (Mcf) toxin with the C-terminal deletion in complex with Arf3

Summary for 8P50

• Entry DOI: 10.2210/pdb8p50/pdb
• EMDB information: 17435
• Descriptor: Toxin protein, ADP-ribosylation factor 3, GUANOSINE-5'-TRIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: bacterial toxin, arf, toxin
• Biological source: Photorhabdus luminescens; More
• Total number of polymer chains: 2
• Total formula weight: 346694.94

Authors

Belyy, A.,Heilen, P.,Hofnagel, O.,Raunser, S. (deposition date: 2023-05-23, release date: 2023-11-01, Last modification date: 2023-12-27)

Primary citation

Belyy, A.,Heilen, P.,Hagel, P.,Hofnagel, O.,Raunser, S.
Structure and activation mechanism of the Makes caterpillars floppy 1 toxin.
Nat Commun, 14:8226-8226, 2023

PubMed Abstract: The bacterial Makes caterpillars floppy 1 (Mcf1) toxin promotes apoptosis in insects, leading to loss of body turgor and death. The molecular mechanism underlying Mcf1 intoxication is poorly understood. Here, we present the cryo-EM structure of Mcf1 from Photorhabdus luminescens, revealing a seahorse-like shape with a head and tail. While the three head domains contain two effectors, as well as an activator-binding domain (ABD) and an autoprotease, the tail consists of two putative translocation and three putative receptor-binding domains. Rearrangement of the tail moves the C-terminus away from the ABD and allows binding of the host cell ADP-ribosylation factor 3, inducing conformational changes that position the cleavage site closer to the protease. This distinct activation mechanism that is based on a hook-loop interaction results in three autocleavage reactions and the release of two toxic effectors. Unexpectedly, the BH3-like domain containing ABD is not an active effector. Our findings allow us to understand key steps of Mcf1 intoxication at the molecular level.

PubMed: 38086871
DOI: 10.1038/s41467-023-44069-2

Experimental method

ELECTRON MICROSCOPY (4.04 Å)