4HT5

CO2 concentrating mechanism protein P, CcmP form 1

Summary for 4HT5

• Entry DOI: 10.2210/pdb4ht5/pdb
• Related: 4HT7
• Descriptor: CO2 concentrating mechanism protein P (2 entities in total)
• Functional Keywords: bmc, carboxysome, protein binding
• Biological source: Synechococcus elongatus
• Total number of polymer chains: 6
• Total formula weight: 149077.55

Authors

Cai, F.,Sutter, M.,Kerfeld, C.A. (deposition date: 2012-10-31, release date: 2013-04-17, Last modification date: 2024-02-28)

Primary citation

Cai, F.,Sutter, M.,Cameron, J.C.,Stanley, D.N.,Kinney, J.N.,Kerfeld, C.A.
The structure of CcmP, a tandem bacterial microcompartment domain protein from the beta-carboxysome, forms a subcompartment within a microcompartment.
J.Biol.Chem., 288:16055-16063, 2013

PubMed Abstract: The carboxysome is a bacterial organelle found in all cyanobacteria; it encapsulates CO2 fixation enzymes within a protein shell. The most abundant carboxysome shell protein contains a single bacterial microcompartment (BMC) domain. We present in vivo evidence that a hypothetical protein (dubbed CcmP) encoded in all β-cyanobacterial genomes is part of the carboxysome. We show that CcmP is a tandem BMC domain protein, the first to be structurally characterized from a β-carboxysome. CcmP forms a dimer of tightly stacked trimers, resulting in a nanocompartment-containing shell protein that may weakly bind 3-phosphoglycerate, the product of CO2 fixation. The trimers have a large central pore through which metabolites presumably pass into the carboxysome. Conserved residues surrounding the pore have alternate side-chain conformations suggesting that it can be open or closed. Furthermore, CcmP and its orthologs in α-cyanobacterial genomes form a distinct clade of shell proteins. Members of this subgroup are also found in numerous heterotrophic BMC-associated gene clusters encoding functionally diverse bacterial organelles, suggesting that the potential to form a nanocompartment within a microcompartment shell is widespread. Given that carboxysomes and architecturally related bacterial organelles are the subject of intense interest for applications in synthetic biology/metabolic engineering, our results describe a new type of building block with which to functionalize BMC shells.

PubMed: 23572529
DOI: 10.1074/jbc.M113.456897

Experimental method

X-RAY DIFFRACTION (2.51 Å)