Title: An improved crystal structure of C-phycoerythrin from the marine cyanobacterium Phormidium sp. A09DM

Abstract

C-Phycoerythrin (PE) from Phormidium sp. A09DM has been crystallized using different conditions and its structure determined to atomic resolution (1.14 Å). In order for the pigment present, phycoerythrobilin (PEB), to function as an efficient light-harvesting molecule it must be held rigidly (Kupka and Scheer in Biochim Biophys Acta 1777:94–103, 2008) and, moreover, the different PEB molecules in PE must be arranged, relative to each other, so as to promote efficient energy transfer between them. This improved structure has allowed us to define in great detail the structure of the PEBs and their binding sites. These precise structural details will facilitate theoretical calculations of each PEB’s spectroscopic properties. It was possible, however, to suggest a model for which chromophores contribute to the different regions of absorption spectrum and propose a tentative scheme for energy transfer. We show that some subtle differences in one of these PEB binding sites in two of the 12 subunits are caused by crystal contacts between neighboring hexamers in the crystal lattice. This explains some of the differences seen in previous lower resolution structures determined at two different pH values (Kumar et al. in Photosyn Res 129:17–28, 2016).

Authors:

Sonani, Ravi R. ^[1]; Roszak, Aleksander W. ^[2]; Ortmann de Percin Northumberland, Claire ^[2]; Madamwar, Datta ^[1]; Cogdell, Richard J. ^[2]

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+ Show Author Affiliations

1. Sardar Patel University, Anand (India)
2. Univ. of Glasgow, Scotland (United Kingdom)

Publication Date:

2017-09-16

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

OSTI Identifier:

1469862

Grant/Contract Number:  

SC0001035

Resource Type:

Accepted Manuscript

Journal Name:

Photosynthesis Research

Additional Journal Information:

Journal Volume: 135; Journal Issue: 1-3; Related Information: PARC partners with Washington University in St. Louis (lead); University of California, Riverside; University of Glasgow, UK; Los Alamos National Laboratory; University of New Mexico; New Mexico Corsortium; North Carolina State University; Northwestern University; Oak Ridge National Laboratory; University of Pennsylvania; Sandia National Laboratories; University of Sheffield, UK; Journal ID: ISSN 0166-8595

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Photosynthesis; Cyanobacteria; Phycobilisomes; Phycoerythrin; PEB chromophores; Atomic resolution crystal structure