4TUM

Crystal structure of Ankyrin Repeat Domain of AKR2

Summary for 4TUM

• Entry DOI: 10.2210/pdb4tum/pdb
• Descriptor: Ankyrin repeat domain-containing protein 2 (2 entities in total)
• Functional Keywords: protein binding
• Biological source: Arabidopsis thaliana (Mouse-ear cress)
• Total number of polymer chains: 5
• Total formula weight: 69927.64

Authors

Gwon, G.H.,Cho, Y. (deposition date: 2014-06-24, release date: 2014-09-24, Last modification date: 2023-12-27)

Primary citation

Kim, D.H.,Park, M.J.,Gwon, G.H.,Silkov, A.,Xu, Z.Y.,Yang, E.C.,Song, S.,Song, K.,Kim, Y.,Yoon, H.S.,Honig, B.,Cho, W.,Cho, Y.,Hwang, I.
An Ankyrin Repeat Domain of AKR2 Drives Chloroplast Targeting through Coincident Binding of Two Chloroplast Lipids.
Dev.Cell, 30:598-609, 2014

PubMed Abstract: In organellogenesis of the chloroplast from endosymbiotic cyanobacteria, the establishment of protein-targeting mechanisms to the chloroplast should have been pivotal. However, it is still mysterious how these mechanisms were established and how they work in plant cells. Here we show that AKR2A, the cytosolic targeting factor for chloroplast outer membrane (COM) proteins, evolved from the ankyrin repeat domain (ARD) of the host cell by stepwise extensions of its N-terminal domain and that two lipids, monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG), of the endosymbiont were selected to function as the AKR2A receptor. Structural analysis, molecular modeling, and mutational analysis of the ARD identified two adjacent sites for coincidental and synergistic binding of MGDG and PG. Based on these findings, we propose that the targeting mechanism of COM proteins was established using components from both the endosymbiont and host cell through a modification of the protein-protein-interacting ARD into a lipid binding domain.

PubMed: 25203210
DOI: 10.1016/j.devcel.2014.07.026

Experimental method

X-RAY DIFFRACTION (2.3 Å)