Dataset Information

Structural and functional dissection reveals distinct roles of Ca2+-binding sites in the giant adhesin SiiE of Salmonella enterica.

ABSTRACT: The giant non-fimbrial adhesin SiiE of Salmonella enterica mediates the first contact to the apical site of epithelial cells and enables subsequent invasion. SiiE is a 595 kDa protein composed of 53 repetitive bacterial immunoglobulin (BIg) domains and the only known substrate of the SPI4-encoded type 1 secretion system (T1SS). The crystal structure of BIg50-52 of SiiE revealed two distinct Ca2+-binding sites per BIg domain formed by conserved aspartate or glutamate residues. In a mutational analysis Ca2+-binding sites were disrupted by aspartate to serine exchange at various positions in the BIg domains of SiiE. Amounts of secreted SiiE diminish with a decreasing number of intact Ca2+-binding sites. BIg domains of SiiE contain distinct Ca2+-binding sites, with type I sites being similar to other T1SS-secreted proteins and type II sites newly identified in SiiE. We functionally and structurally dissected the roles of type I and type II Ca2+-binding sites in SiiE, as well as the importance of Ca2+-binding sites in various positions of SiiE. Type I Ca2+-binding sites were critical for efficient secretion of SiiE and a decreasing number of type I sites correlated with reduced secretion. Type II sites were less important for secretion, stability and surface expression of SiiE, however integrity of type II sites in the C-terminal portion was required for the function of SiiE in mediating adhesion and invasion.

SUBMITTER: Peters B

PROVIDER: S-EPMC5466336 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Structural and functional dissection reveals distinct roles of Ca2+-binding sites in the giant adhesin SiiE of Salmonella enterica.

Peters Britta B Stein Johanna J Klingl Stefan S Sander Nathalie N Sandmann Achim A Taccardi Nicola N Sticht Heinrich H Gerlach Roman G RG Muller Yves A YA Hensel Michael M

PLoS pathogens 20170530 5

The giant non-fimbrial adhesin SiiE of Salmonella enterica mediates the first contact to the apical site of epithelial cells and enables subsequent invasion. SiiE is a 595 kDa protein composed of 53 repetitive bacterial immunoglobulin (BIg) domains and the only known substrate of the SPI4-encoded type 1 secretion system (T1SS). The crystal structure of BIg50-52 of SiiE revealed two distinct Ca2+-binding sites per BIg domain formed by conserved aspartate or glutamate residues. In a mutational ana ...[more]

PMID: 28558023

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Dataset Information

Structural and functional dissection reveals distinct roles of Ca2+-binding sites in the giant adhesin SiiE of Salmonella enterica.

Publications

Structural and functional dissection reveals distinct roles of Ca2+-binding sites in the giant adhesin SiiE of Salmonella enterica.

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