52
V. K. Kannaujiya et al.
In ceratin cyanobacterium such as Synechocystis sp. PCC 6803, CpcE/F proteins
have HEAT repeat motifs in nucleotide sequence which facilitate interaction for stable
conformation of proteins (Morimoto et al. 2003). Another type of CpeF is required for
ligation and functionalization of chromophore from Cys-48/Cys-59 residue in CpeB
of PE subunits in the presence of chaperone-like proteins CpcZ (Kronfel et al. 2019).
However, S/U-type bilin lyase is expressed as CpeS, CpeU, CpcS, CpcU, and CpcV
proteins (Kannaujiya et al. 2017d). Various types of CpcS exist in cyanobacteria
such as Synechococcus sp. PCC7002 (CpcS-I), marine Synechococcus sp. (CpcSII), Anabaena sp. PCC 7120 (CpcS-III) which catalyze the chromophore attachment
reaction of β-PC, β-APC, and PEB chromophores (Shen et al. 2008) (Fig. 3.4).
Sometimes, null mutants (cpcS-I and cpcU) in Synechococcus sp. PCC 7002
have also affected the productivity of PC (Kannaujiya et al. 2017d, Shen et al. 2008).
S/U lyase exhibits broad substrate association with Cys residue in PBPs subunits
as compared to E/F-type (Scheer and Zhao 2008). More specifically, they catalyze
chromophores’ attachment reaction at Cys-81 residue in allophycocyanins and Cys84 in β-subunits in PC, PE, and PEC (Zhao et al. 2017). CpcS-III is structurally
dimeric in nature and found in T. elongatus BP1 (Kuzin et al. 2007). Most of lyase
Fig. 3.4 Model of bilin lyase-induced post-transcriptional modification and functionalization of
biosynthesis of phycocyanin, phycoerythrin, and allophycocyanin to form a complete structure of
phycobilisomes. (Adapted and modified from Kannaujiya et al. 2017d)
V. K. Kannaujiya et al.
In ceratin cyanobacterium such as Synechocystis sp. PCC 6803, CpcE/F proteins
have HEAT repeat motifs in nucleotide sequence which facilitate interaction for stable
conformation of proteins (Morimoto et al. 2003). Another type of CpeF is required for
ligation and functionalization of chromophore from Cys-48/Cys-59 residue in CpeB
of PE subunits in the presence of chaperone-like proteins CpcZ (Kronfel et al. 2019).
However, S/U-type bilin lyase is expressed as CpeS, CpeU, CpcS, CpcU, and CpcV
proteins (Kannaujiya et al. 2017d). Various types of CpcS exist in cyanobacteria
such as Synechococcus sp. PCC7002 (CpcS-I), marine Synechococcus sp. (CpcSII), Anabaena sp. PCC 7120 (CpcS-III) which catalyze the chromophore attachment
reaction of β-PC, β-APC, and PEB chromophores (Shen et al. 2008) (Fig. 3.4).
Sometimes, null mutants (cpcS-I and cpcU) in Synechococcus sp. PCC 7002
have also affected the productivity of PC (Kannaujiya et al. 2017d, Shen et al. 2008).
S/U lyase exhibits broad substrate association with Cys residue in PBPs subunits
as compared to E/F-type (Scheer and Zhao 2008). More specifically, they catalyze
chromophores’ attachment reaction at Cys-81 residue in allophycocyanins and Cys84 in β-subunits in PC, PE, and PEC (Zhao et al. 2017). CpcS-III is structurally
dimeric in nature and found in T. elongatus BP1 (Kuzin et al. 2007). Most of lyase
Fig. 3.4 Model of bilin lyase-induced post-transcriptional modification and functionalization of
biosynthesis of phycocyanin, phycoerythrin, and allophycocyanin to form a complete structure of
phycobilisomes. (Adapted and modified from Kannaujiya et al. 2017d)