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Acidianus, Sulfolobus and Metallosphaera surface layers: structure, composition and gene expression.

Veith, Andreas and Klingl, Andreas and Zolghadr, Behnam and Lauber, Karin and Mentele, Reinhard and Lottspeich, Friedrich and Rachel, Reinhard and Albers, Sonja-Verena and Kletzin, Arnulf (2009):
Acidianus, Sulfolobus and Metallosphaera surface layers: structure, composition and gene expression.
In: Molecular microbiology, pp. 58-72, 73, (1), ISSN 1365-2958,
[Article]

Abstract

The cell walls of Sulfolobales species consist of proteinaceous S-layers assembled from two polypeptides, SlaA and SlaB. We isolated the large S-layer protein of Acidianus ambivalens and both S-layer subunits of Sulfolobus solfataricus and Metallosphaera sedula, respectively. The slaAB genes, lying adjacently in the chromosomes, are constitutively transcribed as bicistronic operons in A. ambivalens and S. solfataricus. A smaller slaA transcript appeared in Northern hybridizations of A. ambivalens RNA. PCRs experiments showed that 80-85% of the transcripts stop at an oligo-T terminator downstream of slaA while 15-20% are read through to a second terminator downstream of slaB. The bicistronic operons including promoter and terminator regions are conserved in the Sulfolobales. While no SlaA homologue is found outside the Sulfolobales, SlaB is distantly similar to S-layer proteins of other Crenarchaeota, e.g. the Staphylothermus marinus tetrabrachion. Molecular modelling suggests SlaBs to be composed of 2-3 consecutive beta sandwich domains, a coiled-coil domain of 15-17 nm in length and a C-terminal transmembrane helix. Electron microscopy shows crystalline protein arrays with triangular and hexagonal pores. We propose that the mushroom-shaped 'unit cells' of the Sulfolobales' S-layers consist of three SlaBs anchoring the complex in the membrane and six SlaAs forming the detergent-resistant outer sacculus.

Item Type: Article
Erschienen: 2009
Creators: Veith, Andreas and Klingl, Andreas and Zolghadr, Behnam and Lauber, Karin and Mentele, Reinhard and Lottspeich, Friedrich and Rachel, Reinhard and Albers, Sonja-Verena and Kletzin, Arnulf
Title: Acidianus, Sulfolobus and Metallosphaera surface layers: structure, composition and gene expression.
Language: English
Abstract:

The cell walls of Sulfolobales species consist of proteinaceous S-layers assembled from two polypeptides, SlaA and SlaB. We isolated the large S-layer protein of Acidianus ambivalens and both S-layer subunits of Sulfolobus solfataricus and Metallosphaera sedula, respectively. The slaAB genes, lying adjacently in the chromosomes, are constitutively transcribed as bicistronic operons in A. ambivalens and S. solfataricus. A smaller slaA transcript appeared in Northern hybridizations of A. ambivalens RNA. PCRs experiments showed that 80-85% of the transcripts stop at an oligo-T terminator downstream of slaA while 15-20% are read through to a second terminator downstream of slaB. The bicistronic operons including promoter and terminator regions are conserved in the Sulfolobales. While no SlaA homologue is found outside the Sulfolobales, SlaB is distantly similar to S-layer proteins of other Crenarchaeota, e.g. the Staphylothermus marinus tetrabrachion. Molecular modelling suggests SlaBs to be composed of 2-3 consecutive beta sandwich domains, a coiled-coil domain of 15-17 nm in length and a C-terminal transmembrane helix. Electron microscopy shows crystalline protein arrays with triangular and hexagonal pores. We propose that the mushroom-shaped 'unit cells' of the Sulfolobales' S-layers consist of three SlaBs anchoring the complex in the membrane and six SlaAs forming the detergent-resistant outer sacculus.

Journal or Publication Title: Molecular microbiology
Volume: 73
Number: 1
Divisions: 10 Department of Biology > Sulfur Biochemistry and Microbial Bioenergetics
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10 Department of Biology
Date Deposited: 01 Sep 2009 10:28
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