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Publication Abstract from PubMed

The photosynthetic bacterial phycobiliprotein lyases, also called CpcT lyases, catalyze the biogenesis of phycobilisome, a light-harvesting antenna complex, through the covalent attachment of chromophores to the antenna proteins. The Arabidopsis CRUMPLED LEAF (CRL) protein is a homolog of the cyanobacterial CpcT lyase. Loss of CRL leads to multiple lesions including localized foliar cell death, constitutive expression of stress-related nuclear genes, abnormal cell cycle, and impaired plastid division. Notwithstanding the apparent phenotypes, the function of CRL remains still elusive. To gain insight into the CRL function, we examined whether CRL still retains the capacity to bind with the bacterial chromophore phycocyanobilin (PCB) and its plant analog phytochromobilin (PPhiB). The revealed structure of the CpcT domain of CRL was nearly comparable to that of the CpcT lyase, despite the lower sequence identity. The subsequent in vitro biochemical assay found, as shown for the CpcT lyase, that PCB/PPhiB binds to the CRL dimer. However, some mutant forms of CRL, substantially compromised in their bilin-binding aptitude, still restore the crl-induced multiple lesions. These results suggest that although CRL retains the bilin-binding pocket, it seems not functionally associated with the crl-induced multiple lesions. Supporting Information.

The Arabidopsis CRUMPLED LEAF protein, a homolog of the cyanobacterial bilin lyase, retains the bilin-binding pocket for a yet unknown function.,Wang F, Fang J, Guan K, Luo S, Dogra V, Li B, Ma D, Zhao X, Lee KP, Sun P, Xin J, Liu T, Xing W, Kim C Plant J. 2020 Aug 29. doi: 10.1111/tpj.14974. PMID:32860438^[5]

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