5E4W

Crystal structure of cpSRP43 chromodomains 2 and 3 in complex with the Alb3 tail

Summary for 5E4W

• Entry DOI: 10.2210/pdb5e4w/pdb
• Descriptor: Thioredoxin-1, Signal recognition particle 43 kDa protein, chloroplastic, Inner membrane protein ALBINO3, chloroplastic, ... (6 entities in total)
• Functional Keywords: signal recognition particle, chromodomain, membrane insertase alb3, chloroplast, signaling protein, transport protein
• Biological source: Escherichia coli O157:H7; More
• Cellular location: Plastid, chloroplast stroma : O22265; Plastid, chloroplast thylakoid membrane ; Multi- pass membrane protein : Q8LBP4
• Total number of polymer chains: 6
• Total formula weight: 50122.44

Authors

Horn, A.,Ahmed, Y.L.,Wild, K.,Sinning, I. (deposition date: 2015-10-07, release date: 2015-12-02, Last modification date: 2024-10-09)

Primary citation

Horn, A.,Hennig, J.,Ahmed, Y.L.,Stier, G.,Wild, K.,Sattler, M.,Sinning, I.
Structural basis for cpSRP43 chromodomain selectivity and dynamics in Alb3 insertase interaction.
Nat Commun, 6:8875-8875, 2015

PubMed Abstract: Canonical membrane protein biogenesis requires co-translational delivery of ribosome-associated proteins to the Sec translocase and depends on the signal recognition particle (SRP) and its receptor (SR). In contrast, high-throughput delivery of abundant light-harvesting chlorophyll a,b-binding proteins (LHCPs) in chloroplasts to the Alb3 insertase occurs post-translationally via a soluble transit complex including the cpSRP43/cpSRP54 heterodimer (cpSRP). Here we describe the molecular mechanisms of tethering cpSRP to the Alb3 insertase by specific interaction of cpSRP43 chromodomain 3 with a linear motif in the Alb3 C-terminal tail. Combining NMR spectroscopy, X-ray crystallography and biochemical analyses, we dissect the structural basis for selectivity of chromodomains 2 and 3 for their respective ligands cpSRP54 and Alb3, respectively. Negative cooperativity in ligand binding can be explained by dynamics in the chromodomain interface. Our study provides a model for membrane recruitment of the transit complex and may serve as a prototype for a functional gain by the tandem arrangement of chromodomains.

PubMed: 26568381
DOI: 10.1038/ncomms9875

Experimental method

X-RAY DIFFRACTION (2.8 Å)