Photosynthesis Research

, Volume 93, Issue 1, pp 27–43

The presence of multidomain linkers determines the bundle-shape structure of the phycobilisome of the cyanobacterium Gloeobacter violaceus PCC 7421

Authors

  • David W. Krogmann
    • Department of BiochemistryPurdue University
  • Bertha Pérez-Gómez
    • Departmento de BioquímicaCentro de Investigación y Estudios Avanzados-IPN
  • Emma Berta Gutiérrez-Cirlos
    • Unidad de Biomedicina FES-Iztacala UNAM
  • Alicia Chagolla-López
    • Cinvestav-Unidad Irapuato
  • Luis González de la Vara
    • Cinvestav-Unidad Irapuato
    • Departmento de BioquímicaCentro de Investigación y Estudios Avanzados-IPN
Original paper

DOI: 10.1007/s11120-007-9133-9

Cite this article as:
Krogmann, D.W., Pérez-Gómez, B., Gutiérrez-Cirlos, E.B. et al. Photosynth Res (2007) 93: 27. doi:10.1007/s11120-007-9133-9

Abstract

The complete genome sequence of Gloeobacter violaceus [Nakamura et al. (2003a, b) DNA Res 10:37–45, 181–201] allows us to understand better the structure of the phycobilisomes (PBS) of this cyanobacterium. Genomic analysis revealed peculiarities in these PBS: the presence of genes for two multidomain linker proteins, a core membrane linker with four repetitive sequences (REP domains), the absence of rod core linkers, two sets of phycocyanin (PC) α and β subunits, two copies of a rod PC associated linker (CpcC), and two rod cap associated linkers (CpcD). Also, there is one ferredoxin–NADP+ oxidoreductase with only two domains. The PBS proteins were investigated by gel electrophoresis, amino acid sequencing and peptide mass fingerprinting (PMF). The two unique multidomain linkers contain three REP domains with high similarity and these were found to be in tandem and were separated by dissimilar Arms. One of these, with a mass of 81 kDa, is found in heavy PBS fragments rich in PC. We propose that it links six PC hexamers in two parallel rows in the rods. The other unique linker has a mass of 91 kDa and is easily released from the heavy fragments of PBS. We propose that this links the rods to the core. The presence of these multidomain linkers could explain the bundle shaped rods of the PBS. The presence of 4 REP domains in the core membrane linker protein (129 kDa) was established by PMF. This core linker may hold together 16 AP trimers of the pentacylindrical core, or alternatively, a tetracylindrical core of the PBS of G. violaceus.

Keywords

CyanobacteriumGloeobacter violaceusPhycobilisomeMultidomain linkers

Abbreviations

AP

Allophycocyanin

apcAB

Gene encoding the α and β subunits of allophycocyanin

apcC

Gene encoding the 8–kDa core linker polypeptide

ApcE

The 129-kDa core membrane linker phycobiliprotein

A.U.

Absorbance units

cpcBA

Genes encoding the α and β subunits of phycocyanin

cpcC1

Gene encoding the PC-rod linker polypeptide

cpcD

Gene encoding the 9-kDa rod linker polypeptide

cpcG

Gene encoding the rod-core linker polypeptide

DCPIP

Dichlorophenol-indophenol

DMF

Dimethyl-formamide

EDTA

Ethylenediamine tetraacetic acid

FNR

Ferredoxin-NADP+ oxidoreductase

FNR-2D

FNR containing only the two catalytic domains

FNR-3D

FNR containing three domains (the CpcD-like domain and two catalytic domains)

F.U.

Fluorescence units

LC8

Core linker polypeptide of 8 kDa

LCM129

LR9, the 9-kDa, phycocyanin-associated rod linker polypeptide

LR33

CpcC, the PC-rod linker polypeptide

CpcG

The rod core linker polypeptide

PAGE

Polyacrylamide gel electrophoresis

PBP(s)

Phycobiliprotein(s)

PBS

Phycobilisome(s)

PC

Phycocyanin

PE

Phycoerythrin

petH

Gene encoding FNR

PMF

Protein mass fingerprinting

PMSF

Phenyl-methylsulfonyl fluoride

REP

Repetitive sequence

SDS

Sodium dodecylsulfate

WCE

Whole-cell extract

Copyright information

© Springer Science+Business Media B.V. 2007