7O54

Crystal structure of the carbonic anhydrase-like domain of CcmM in complex with the C-terminal 17 residues of CcaA from Synechococcus elongatus (strain PCC 7942)

Summary for 7O54

• Entry DOI: 10.2210/pdb7o54/pdb
• Related: 7O4Z
• Descriptor: Carboxysome assembly protein CcmM, Carbonic anhydrase, NICKEL (II) ION, ... (5 entities in total)
• Functional Keywords: protein binding carboxysome, photosynthesis
• Biological source: Synechococcus elongatus (strain PCC 7942 / FACHB-805) (Anacystis nidulans R2); More
• Total number of polymer chains: 2
• Total formula weight: 21320.17

Authors

Zang, K.,Wang, H.,Hartl, F.U.,Hayer-Hartl, M. (deposition date: 2021-04-07, release date: 2021-11-10, Last modification date: 2024-01-31)

Primary citation

Zang, K.,Wang, H.,Hartl, F.U.,Hayer-Hartl, M.
Scaffolding protein CcmM directs multiprotein phase separation in beta-carboxysome biogenesis.
Nat.Struct.Mol.Biol., 28:909-922, 2021

PubMed Abstract: Carboxysomes in cyanobacteria enclose the enzymes Rubisco and carbonic anhydrase to optimize photosynthetic carbon fixation. Understanding carboxysome assembly has implications in agricultural biotechnology. Here we analyzed the role of the scaffolding protein CcmM of the β-cyanobacterium Synechococcus elongatus PCC 7942 in sequestrating the hexadecameric Rubisco and the tetrameric carbonic anhydrase, CcaA. We find that the trimeric CcmM, consisting of γCAL oligomerization domains and linked small subunit-like (SSUL) modules, plays a central role in mediation of pre-carboxysome condensate formation through multivalent, cooperative interactions. The γCAL domains interact with the C-terminal tails of the CcaA subunits and additionally mediate a head-to-head association of CcmM trimers. Interestingly, SSUL modules, besides their known function in recruiting Rubisco, also participate in intermolecular interactions with the γCAL domains, providing further valency for network formation. Our findings reveal the mechanism by which CcmM functions as a central organizer of the pre-carboxysome multiprotein matrix, concentrating the core components Rubisco and CcaA before β-carboxysome shell formation.

PubMed: 34759380
DOI: 10.1038/s41594-021-00676-5

Experimental method

X-RAY DIFFRACTION (1.63 Å)