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Publication Abstract from PubMed

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(O77)) 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(O77) 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 alpha and beta 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(O77). The findings of this study indicate that the octameric CPC(O77) is a naturally occurring form in the thermophilic cyanobacterium Thermoleptolyngbya sp. O-77.

Disassembly and reassembly of the non-conventional thermophilic C-phycocyanin.,Nguyen HK, Minato T, Teramoto T, Ogo S, Kakuta Y, Yoon KS J Biosci Bioeng. 2024 Mar;137(3):179-186. doi: 10.1016/j.jbiosc.2023.12.015. Epub , 2024 Jan 18. PMID:38238241^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.