7yth | pdb_00007yth

Structure of OCPx1 from Nostoc flagelliforme CCNUN1

spinqualitylabelsall models 7yth, resolution 1.93Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7yth is a 4 chain structure with sequence from Nostoc flagelliforme CCNUN1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.93Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A2K8SJT8_9NOSO Publication Abstract from PubMed Orange carotenoid protein (OCP) is a photoactive protein that participates in the photoprotection of cyanobacteria. There are two full-length OCP proteins, four N-terminal paralogs (helical carotenoid protein, HCP), and one C-terminal domain-like carotenoid protein (CCP) found in Nostoc flagelliforme, a desert cyanobacterium. All HCPs (HCP1-3 and HCP6) from N. flagelliforme demonstrated their excellent singlet oxygen quenching activities, in which HCP2 was the strongest singlet oxygen quencher compared with others. Two OCPs, OCPx1 and OCPx2, were not involved in singlet oxygen scavenging; instead, they functioned as phycobilisome fluorescence quenchers. The fast-acting OCPx1 showed more effective photoactivation and stronger phycobilisome fluorescence quenching compared to OCPx2, which behaved differently from all reported OCP paralogs. The resolved crystal structure and mutant analysis revealed that Trp111 and Met125 play essential roles in OCPx2, which is dominant and long-acting. The resolved crystal structure of OCPx2 is maintained in a monomer state and showed more flexible regulation in energy quenching activities compared with the packed oligomer of OCPx1. The recombinant apo-CCP obtained the carotenoid pigment from holo-HCPs and holo-OCPx1 of N. flagelliforme. No such carotenoid transferring processes were observed between apo-CCP and holo-OCPx2. The close phylogenetic relationship of OCP paralogs from subaerial Nostoc species indicates an adaptive evolution toward development of photoprotection: protecting cellular metabolism against singlet oxygen damage using HCPs and against excess energy captured by active phycobilisomes using two different working modes of OCPx. Functional specialization of expanded orange carotenoid protein paralogs in subaerial Nostoc species.,Yang YW, Liu K, Huang D, Yu C, Chen SZ, Chen M, Qiu BS Plant Physiol. 2023 Apr 18:kiad234. doi: 10.1093/plphys/kiad234. PMID:37070859 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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