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

ACCESS DATA

Publications

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

Similar Datasets

Project description:The prevalence, among human clinical cases, of Salmonella enterica serotype 4,5,12:i:-, a serotype antigenically similar to Salmonella enterica serotype Typhimurium but lacking second-phase flagellar antigens, has increased considerably over the last 10 years. To probe the evolution and ecology of this emerging serotype, we characterized 190 Salmonella isolates initially classified as Salmonella serotypes 4,5,12:i:- (n = 90) and Typhimurium (n = 100) and obtained from various sources in the United States and Spain. These isolates were characterized into six sequence types (determined by multilocus sequence typing [MLST]) and 79 pulsed-field gel electrophoresis types. The majority of Salmonella serotype 4,5,12:i:- and Typhimurium isolates (85 and 84 isolates, respectively) represented a single MLST type. Existing genome information revealed different genome deletions (which included genes responsible for phase 2 flagellum expression) in four Spanish Salmonella serotype 4,5,12:i:- isolates and one U.S. Salmonella serotype 4,5,12:i:- isolate. Fifty-nine isolates of both serotypes, representing different sources and geographical locations as well as different molecular subtypes, were thus screened for the presence of six genes and one specific region, all of which were previously found to show variable presence among Salmonella serotype 4,5,12:i:- and Typhimurium strains. All Salmonella serotype 4,5,12:i:- isolates lacked the phase 2 flagella genes fljA and fljB, which were present in all Salmonella serotype Typhimurium isolates. While all Spanish Salmonella serotype 4,5,12:i:- isolates carried the same deletion surrounding fljAB, all but two U.S. isolates showed a different genomic deletion; the two atypical U.S. isolates represented the "Spanish" deletion genotype and a unique deletion genotype. Salmonella serotype 4,5,12:i:- thus appears to represent at least two common clones, which cannot easily be differentiated with standard diagnostic procedures.

Project description:Labile [4Fe-4S](2+) clusters found at the active sites of many dehydratases are susceptible to damage by univalent oxidants that convert the clusters to an inactive [3Fe-4S](1+) form. Bacteria repair damaged clusters in a process that does not require de novo protein synthesis or the Isc and Suf cluster assembly pathways. The current study investigates the participation of the bacterial frataxin ortholog CyaY and the YggX protein, which are proposed to play roles in iron trafficking and iron-sulfur cluster repair. Previous reports found that individual mutations in cyaY or yggX were not associated with phenotypic changes in Escherichia coli and Salmonella enterica serovar Typhimurium, suggesting that CyaY and YggX might have functionally redundant roles. However, we have found that individual mutations in cyaY or yggX confer enhanced susceptibility to hydrogen peroxide in Salmonella enterica serovar Typhimurium. In addition, inactivation of the stm3944 open reading frame, which is located immediately upstream of cyaY and which encodes a putative inner membrane protein, dramatically enhances the hydrogen peroxide sensitivity of a cyaY mutant. Overexpression of STM3944 reduces the elevated intracellular free iron levels observed in an S. Typhimurium fur mutant and also reduces the total cellular iron content under conditions of iron overload, suggesting that the stm3944-encoded protein may mediate iron efflux. Mutations in cyaY and yggX have different effects on the activities of the iron-sulfur cluster-containing aconitase, serine deaminase, and NADH dehydrogenase I enzymes of S. Typhimurium under basal conditions or following recovery from oxidative stress. In addition, cyaY and yggX mutations have additive effects on 6-phosphogluconate dehydratase-dependent growth during nitrosative stress, and a cyaY mutation reduces Salmonella virulence in mice. Collectively, these results indicate that CyaY and YggX play distinct supporting roles in iron-sulfur cluster biosynthesis and the repair of labile clusters damaged by univalent oxidants. Salmonella experiences oxidative and nitrosative stress within host phagocytes, and CyaY-dependent maintenance of labile iron-sulfur clusters appears to be important for Salmonella virulence.

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.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure