5HGR

Structure of Anabaena (Nostoc) sp. PCC 7120 Orange Carotenoid Protein binding canthaxanthin

Summary for 5HGR

• Entry DOI: 10.2210/pdb5hgr/pdb
• Related: 4XB5
• Descriptor: Orange Carotenoid Protein (OCP), beta,beta-carotene-4,4'-dione (3 entities in total)
• Functional Keywords: carotenoid, photoprotection, cyanobacteria, carotenoid binding protein
• Biological source: Nostoc sp. (strain PCC 7120 / UTEX 2576)
• Total number of polymer chains: 2
• Total formula weight: 73534.10

Authors

Sutter, M.,Leverenz, R.L.,Kerfeld, C.A. (deposition date: 2016-01-08, release date: 2016-11-16, Last modification date: 2024-03-06)

Primary citation

Lopez-Igual, R.,Wilson, A.,Leverenz, R.L.,Melnicki, M.R.,Bourcier de Carbon, C.,Sutter, M.,Turmo, A.,Perreau, F.,Kerfeld, C.A.,Kirilovsky, D.
Different Functions of the Paralogs to the N-Terminal Domain of the Orange Carotenoid Protein in the Cyanobacterium Anabaena sp. PCC 7120.
Plant Physiol., 171:1852-1866, 2016

PubMed Abstract: The photoactive Orange Carotenoid Protein (OCP) is involved in cyanobacterial photoprotection. Its N-terminal domain (NTD) is responsible for interaction with the antenna and induction of excitation energy quenching, while the C-terminal domain is the regulatory domain that senses light and induces photoactivation. In most nitrogen-fixing cyanobacterial strains, there are one to four paralogous genes coding for homologs to the NTD of the OCP. The functions of these proteins are unknown. Here, we study the expression, localization, and function of these genes in Anabaena sp. PCC 7120. We show that the four genes present in the genome are expressed in both vegetative cells and heterocysts but do not seem to have an essential role in heterocyst formation. This study establishes that all four Anabaena NTD-like proteins can bind a carotenoid and the different paralogs have distinct functions. Surprisingly, only one paralog (All4941) was able to interact with the antenna and to induce permanent thermal energy dissipation. Two of the other Anabaena paralogs (All3221 and Alr4783) were shown to be very good singlet oxygen quenchers. The fourth paralog (All1123) does not seem to be involved in photoprotection. Structural homology modeling allowed us to propose specific features responsible for the different functions of these soluble carotenoid-binding proteins.

PubMed: 27208286
DOI: 10.1104/pp.16.00502

Experimental method

X-RAY DIFFRACTION (1.681 Å)