8XF1

Crystal structure of the dissociated C-phycocyanin beta-chain from Thermoleptolyngbya sp. O-77

Summary for 8XF1

• Entry DOI: 10.2210/pdb8xf1/pdb
• Descriptor: C-phycocyanin beta chain, PHYCOCYANOBILIN (3 entities in total)
• Functional Keywords: dissociated subunit, c-phycocyanin, photosynthesis
• Biological source: Leptolyngbya sp. O-77
• Total number of polymer chains: 1
• Total formula weight: 19274.85

Authors

Nguyen, H.K.,Teramoto, T.,Kakuta, Y.,Yoon, K.S. (deposition date: 2023-12-13, release date: 2024-05-22)

Primary citation

Nguyen, H.K.,Minato, T.,Teramoto, T.,Ogo, S.,Kakuta, Y.,Yoon, K.S.
Disassembly and reassembly of the non-conventional thermophilic C-phycocyanin.
J.Biosci.Bioeng., 137:179-186, 2024

PubMed Abstract: C-phycocyanin (CPC), which contains open-chain tetrapyrroles, is a major light-harvesting red-fluorescent protein with an important role in aquatic photosynthesis. Recently, we reported a non-conventional CPC from Thermoleptolyngbya sp. O-77 (CPC) that contains two different structures, i.e., a hexameric structure and a non-conventional octameric structure. However, the assembly and disassembly mechanisms of the non-conventional octameric form of CPC remain unclear. To understand this assembly mechanism, we performed an in vitro experiment to study the disassembly and reassembly behaviors of CPC using isolated CPC subunits. The dissociation of the CPC subunit was performed using a Phenyl-Sepharose column in 20 mM potassium phosphate buffer (pH 6.0) containing 7.0 M urea. For the first time, crystals of isolated CPC subunits were obtained and analyzed after separation. After the removal of urea from the purified α and β subunits, we performed an in vitro reassembly experiment for CPC and analyzed the reconstructed CPC using spectrophotometric and X-ray crystal structure analyses. The crystal structure of the reassembled CPC was nearly identical to that of the original CPC. The findings of this study indicate that the octameric CPC is a naturally occurring form in the thermophilic cyanobacterium Thermoleptolyngbya sp. O-77.

PubMed: 38238241
DOI: 10.1016/j.jbiosc.2023.12.015

Experimental method

X-RAY DIFFRACTION (1.94 Å)