6T6Q

Crystal structure of Toxoplasma gondii Morn1 (extended conformation).

This is a non-PDB format compatible entry.

Summary for 6T6Q

• Entry DOI: 10.2210/pdb6t6q/pdb
• Descriptor: Membrane occupation and recognition nexus protein MORN1 (1 entity in total)
• Functional Keywords: morn repeat, morn1, structural protein, toxoplasma
• Biological source: Toxoplasma gondii (strain ATCC 50861 / VEG)
• Total number of polymer chains: 2
• Total formula weight: 49493.98

Authors

Grishkovskaya, I.,Kostan, J.,Sajko, S.,Morriswood, B.,Djinovic-Carugo, K. (deposition date: 2019-10-18, release date: 2020-11-18, Last modification date: 2024-01-24)

Primary citation

Sajko, S.,Grishkovskaya, I.,Kostan, J.,Graewert, M.,Setiawan, K.,Trubestein, L.,Niedermuller, K.,Gehin, C.,Sponga, A.,Puchinger, M.,Gavin, A.C.,Leonard, T.A.,Svergun, D.I.,Smith, T.K.,Morriswood, B.,Djinovic-Carugo, K.
Structures of three MORN repeat proteins and a re-evaluation of the proposed lipid-binding properties of MORN repeats.
Plos One, 15:e0242677-e0242677, 2020

PubMed Abstract: MORN (Membrane Occupation and Recognition Nexus) repeat proteins have a wide taxonomic distribution, being found in both prokaryotes and eukaryotes. Despite this ubiquity, they remain poorly characterised at both a structural and a functional level compared to other common repeats. In functional terms, they are often assumed to be lipid-binding modules that mediate membrane targeting. We addressed this putative activity by focusing on a protein composed solely of MORN repeats-Trypanosoma brucei MORN1. Surprisingly, no evidence for binding to membranes or lipid vesicles by TbMORN1 could be obtained either in vivo or in vitro. Conversely, TbMORN1 did interact with individual phospholipids. High- and low-resolution structures of the MORN1 protein from Trypanosoma brucei and homologous proteins from the parasites Toxoplasma gondii and Plasmodium falciparum were obtained using a combination of macromolecular crystallography, small-angle X-ray scattering, and electron microscopy. This enabled a first structure-based definition of the MORN repeat itself. Furthermore, all three structures dimerised via their C-termini in an antiparallel configuration. The dimers could form extended or V-shaped quaternary structures depending on the presence of specific interface residues. This work provides a new perspective on MORN repeats, showing that they are protein-protein interaction modules capable of mediating both dimerisation and oligomerisation.

PubMed: 33296386
DOI: 10.1371/journal.pone.0242677

Experimental method

X-RAY DIFFRACTION (2.902 Å)