PDBsum entry 4rmp

Photosynthesis

PDB id: 4rmp

Contents

Protein chains

160 a.a.

161 a.a.

Ligands

CYC ×2

Waters ×179

PDB id:

4rmp

Name:

Photosynthesis

Title:

Crystal structure of allophycocyanin from marine cyanobacterium phormidium sp. A09dm

Structure:

Allophycocyanin. Chain: a. Allophycocyanin. Chain: b

Source:

Phormidium rubidum a09dm. Organism_taxid: 865859. Other_details: marine cyanobacterium isolated from rocky shores of gujarat. Gujarat

Resolution:

2.51Å R-factor: 0.162 R-free: 0.229

Authors:

V.Kumar,G.D.Gupta,R.R.Sonani,D.Madamwar

Key ref:

R.R.Sonani et al. (2015). Crystal Structure of Allophycocyanin from Marine Cyanobacterium Phormidium sp. A09DM. Plos One, 10, e0124580. PubMed id: 25923120 DOI: 10.1371/journal.pone.0124580

Date:

22-Oct-14 Release date: 13-May-15

Protein chain

A0A078K1U6  (A0A078K1U6_9CYAN) -  Allophycocyanin (Fragment) from Phormidium rubidum A09DM

Seq: 153 a.a.

Struc: 160 a.a.*

Protein chain

A0A078K4M9  (A0A078K4M9_9CYAN) -  Allophycocyanin (Fragment) from Phormidium rubidum A09DM

Seq: 155 a.a.

Struc: 161 a.a.*

* PDB and UniProt seqs differ at 5 residue positions (black crosses)

DOI no: 10.1371/journal.pone.0124580

Plos One 10:e0124580 (2015)

PubMed id: 25923120

Crystal Structure of Allophycocyanin from Marine Cyanobacterium Phormidium sp. A09DM.

R.R.Sonani, G.D.Gupta, D.Madamwar, V.Kumar.

ABSTRACT

Isolated phycobilisome (PBS) sub-assemblies have been widely subjected to X-ray crystallography analysis to obtain greater insights into the structure-function relationship of this light harvesting complex. Allophycocyanin (APC) is the phycobiliprotein always found in the PBS core complex. Phycocyanobilin (PCB) chromophores, covalently bound to conserved Cys residues of α- and β- subunits of APC, are responsible for solar energy absorption from phycocyanin and for transfer to photosynthetic apparatus. In the known APC structures, heterodimers of α- and β- subunits (known as αβ monomers) assemble as trimer or hexamer. We here for the first time report the crystal structure of APC isolated from a marine cyanobacterium (Phormidium sp. A09DM). The crystal structure has been refined against all the observed data to the resolution of 2.51 Å to Rwork (Rfree) of 0.158 (0.229) with good stereochemistry of the atomic model. The Phormidium protein exists as a trimer of αβ monomers in solution and in crystal lattice. The overall tertiary structures of α- and β- subunits, and trimeric quaternary fold of the Phormidium protein resemble the other known APC structures. Also, configuration and conformation of the two covalently bound PCB chromophores in the marine APC are same as those observed in fresh water cyanobacteria and marine red algae. More hydrophobic residues, however, constitute the environment of the chromophore bound to α-subunit of the Phormidium protein, owing mainly to amino acid substitutions in the marine protein.