5NVD

Crystal structure of hexameric CBS-CP12 protein from bloom-forming cyanobacteria at 2.5 A resolution in P6322 crystal form

Summary for 5NVD

• Entry DOI: 10.2210/pdb5nvd/pdb
• Descriptor: CBS-CP12 (2 entities in total)
• Functional Keywords: cystathionine beta synthase domain, fusion protein, redox-regulation of photosynthesis, photosynthesis
• Biological source: Microcystis aeruginosa PCC 7806
• Total number of polymer chains: 1
• Total formula weight: 23154.56

Authors

Hackenberg, C.,Hakanpaa, J.,Eigner, C.,Antonyuk, S.V.,Dittmann, E.,Lamzin, V.S. (deposition date: 2017-05-04, release date: 2018-05-30, Last modification date: 2024-11-13)

Primary citation

Hackenberg, C.,Hakanpaa, J.,Cai, F.,Antonyuk, S.,Eigner, C.,Meissner, S.,Laitaoja, M.,Janis, J.,Kerfeld, C.A.,Dittmann, E.,Lamzin, V.S.
Structural and functional insights into the unique CBS-CP12 fusion protein family in cyanobacteria.
Proc. Natl. Acad. Sci. U.S.A., 115:7141-7146, 2018

PubMed Abstract: Cyanobacteria are important photosynthetic organisms inhabiting a range of dynamic environments. This phylum is distinctive among photosynthetic organisms in containing genes encoding uncharacterized cystathionine β-synthase (CBS)-chloroplast protein (CP12) fusion proteins. These consist of two domains, each recognized as stand-alone photosynthetic regulators with different functions described in cyanobacteria (CP12) and plants (CP12 and CBSX). Here we show that CBS-CP12 fusion proteins are encoded in distinct gene neighborhoods, several unrelated to photosynthesis. Most frequently, CBS-CP12 genes are in a gene cluster with thioredoxin A (TrxA), which is prevalent in bloom-forming, marine symbiotic, and benthic mat cyanobacteria. Focusing on a CBS-CP12 from PCC 7806 encoded in a gene cluster with TrxA, we reveal that the domain fusion led to the formation of a hexameric protein. We show that the CP12 domain is essential for hexamerization and contains an ordered, previously structurally uncharacterized N-terminal region. We provide evidence that CBS-CP12, while combining properties of both regulatory domains, behaves different from CP12 and plant CBSX. It does not form a ternary complex with phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase. Instead, CBS-CP12 decreases the activity of PRK in an AMP-dependent manner. We propose that the novel domain architecture and oligomeric state of CBS-CP12 expand its regulatory function beyond those of CP12 in cyanobacteria.

PubMed: 29915055
DOI: 10.1073/pnas.1806668115

Experimental method

X-RAY DIFFRACTION (2.5 Å)