6UEW

Rubisco / CsoS2 N-peptide complex responsible for alpha-carboxysome cargo loading

Summary for 6UEW

• Entry DOI: 10.2210/pdb6uew/pdb
• Descriptor: Ribulose bisphosphate carboxylase large chain, CsoS2 N-peptide fusion, Ribulose bisphosphate carboxylase small chain (3 entities in total)
• Functional Keywords: rubisco, csos2, carboxysome, phase separation, protein binding
• Biological source: Halothiobacillus neapolitanus (strain ATCC 23641 / c2); More
• Total number of polymer chains: 8
• Total formula weight: 276628.10

Authors

Oltrogge, L.M.,Savage, D.F. (deposition date: 2019-09-23, release date: 2019-10-30, Last modification date: 2023-10-11)

Primary citation

Oltrogge, L.M.,Chaijarasphong, T.,Chen, A.W.,Bolin, E.R.,Marqusee, S.,Savage, D.F.
Multivalent interactions between CsoS2 and Rubisco mediate alpha-carboxysome formation.
Nat.Struct.Mol.Biol., 27:281-287, 2020

PubMed Abstract: Carboxysomes are bacterial microcompartments that function as the centerpiece of the bacterial CO-concentrating mechanism by facilitating high CO concentrations near the carboxylase Rubisco. The carboxysome self-assembles from thousands of individual proteins into icosahedral-like particles with a dense enzyme cargo encapsulated within a proteinaceous shell. In the case of the α-carboxysome, there is little molecular insight into protein-protein interactions that drive the assembly process. Here, studies on the α-carboxysome from Halothiobacillus neapolitanus demonstrate that Rubisco interacts with the N terminus of CsoS2, a multivalent, intrinsically disordered protein. X-ray structural analysis of the CsoS2 interaction motif bound to Rubisco reveals a series of conserved electrostatic interactions that are only made with properly assembled hexadecameric Rubisco. Although biophysical measurements indicate that this single interaction is weak, its implicit multivalency induces high-affinity binding through avidity. Taken together, our results indicate that CsoS2 acts as an interaction hub to condense Rubisco and enable efficient α-carboxysome formation.

PubMed: 32123388
DOI: 10.1038/s41594-020-0387-7

Experimental method

X-RAY DIFFRACTION (2.4 Å)