The proteome of the heterocyst cell wall in Anabaena sp. PCC 7120

Abstract

Anabaena sp. PCC 7120 is a filamentous cyanobacterium that serves as a model to analyze prokaryotic cell differentiation, evolutionary development of plastids, and the regulation of nitrogen fixation. The cell wall is the cellular structure in contact with the surrounding medium. To understand the dynamics of the cell wall proteome during cell differentiation, the cell wall from Anabaena heterocysts was enriched and analyzed. In line with the recently proposed continuity of the outer membrane along the Anabaena filament, most of the proteins identified in the heterocyst cell-wall fraction are also present in the cell wall of vegetative cells, even though the lipid content of both membranes is different.

Structure and Conservation of the Periplasmic Targeting Factor Tic22 Protein from Plants and Cyanobacteria

“…2). In contrast, omp85 genes do not show an enhanced expression (23), which might either be a explained by the existence of three distinct genes coding for Omp85-like proteins (23) or by an anyhow very high expression and protein content of this factor (27,41). The enhanced expression of anatic22 during heterocyst development parallels the observation that the insertion mutant of anatic22 does not grow under these conditions (Fig.…”

“…This could suggest that heterocyst formation requires an alteration of the outer membrane proteome. However, the reorganization of the cell wall during heterocyst formation is not accompanied with significant proteome change in terms of the type of proteins (27,41) but may with respect to the quantity of certain factors. The latter notion, however, has not been experimentally confirmed so far.…”

The TolC-like Protein HgdD of the Cyanobacterium Anabaena sp. PCC 7120 Is Involved in Secondary Metabolite Export and Antibiotic Resistance

“…Consistent with this notion, none of the Anabaena sp. genes coding for putative porins (18,19,22) were altered in their expression in the hgdD mutant used in this study (Fig. 5).…”

“…PCC 7120 (referred to hereafter as Anabaena sp.) has been identified by proteomic analysis (18,19), and its relation to the TolC family was confirmed by homology modeling and analysis of the corresponding mutant (5,7,20). Anabaena sp.…”

Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen inAnabaenasp. Strain PCC 7120

“…Recently, we reported the presence of a putatively TonBdependent transporter (Alr0397) in the outer membranes of Anabaena vegetative cells and heterocysts (37,38). Close to alr0397 are genes with similarity to the aerobactin biosynthesis genes.…”