Abstract：
:Type III secretion systems are found in many Gram-negative bacteria. They are activated by contact with eukaryotic cells and inject virulence proteins inside them. Host cell detection requires a protein complex located at the tip of the device's external injection needle. The Shigella tip complex (TC) is composed of IpaD, a hydrophilic protein, and IpaB, a hydrophobic protein, which later forms part of the injection pore in the host membrane. Here we used labelling and crosslinking methods to show that TCs from a ΔipaB strain contain five IpaD subunits while the TCs from wild-type can also contain one IpaB and four IpaD subunits. Electron microscopy followed by single particle and helical image analysis was used to reconstruct three-dimensional images of TCs at ∼ 20 Å resolution. Docking of an IpaD crystal structure, constrained by the crosslinks observed, reveals that TC organisation is different from that of all previously proposed models. Our findings suggest new mechanisms for TC assembly and function. The TC is the only site within these secretion systems targeted by disease-protecting antibodies. By suggesting how these act, our work will allow improvement of prophylactic and therapeutic strategies.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Cheung M,Shen DK,Makino F,Kato T,Roehrich AD,Martinez-Argudo I,Walker ML,Murillo I,Liu X,Pain M,Brown J,Frazer G,Mantell J,Mina P,Todd T,Sessions RB,Namba K,Blocker AJdoi
10.1111/mmi.12843subject
Has Abstractpub_date
2015-01-01 00:00:00pages
31-50issue
1eissn
0950-382Xissn
1365-2958journal_volume
95pub_type
杂志文章abstract：:Exposure of bacterial cells to temperature changes induces the synthesis of a set proteins. We investigated the control of expression of the cspA gene, coding for the major cold-shock protein of Escherichia coli. This protein was shown to be transiently induced upon shift to low temperature. We demonstrated that the c...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1996.363898.x
更新日期：1996-01-01 00:00:00
abstract：:Thymidylate, an essential building block of DNA, is synthesized either from deoxyuridylate by thymidylate synthase (TS) or thymidine (dT) by thymidine kinase (TK). Thymidylate kinase (TMPK) phosphorylates dTMP to dTTP. Thymidine phosphorylase (TP) catalyses reversible phosphorolysis of dT. Using transposon mutagenesis...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2010.07298.x
更新日期：2010-09-01 00:00:00
abstract：:Filamentous hemagglutinin (FHA) is a critically important virulence factor produced by Bordetella species that cause respiratory infections in humans and other animals. It is also a prototypical member of the widespread two partner secretion (TPS) pathway family of proteins. First synthesized as a ~370 kDa protein cal...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/mmi.14318
更新日期：2019-09-01 00:00:00
abstract：:We report the construction and the expression in Escherichia coli of three different fusion genes encoding the extended human IgG3 hinge region (Hi) fused in-phase to the C-terminal end of bacterial TEM1 beta-lactamase (Bla). In the first fusion gene blahi, TEM1 beta-lactamase (Bla). In the first fusion gene blahi, th...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1992.tb01394.x
更新日期：1992-08-01 00:00:00
abstract：:Chlamydiae are obligate intracellular bacteria which undergo a unique developmental cycle, alternating between non-replicative elementary bodies (EBs) and replicative reticulate bodies (RBs). The transition from RB to EB is characterized by condensation of the chromosome into a dense nucleoid structure. The chlamydial...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1993.tb01689.x
更新日期：1993-07-01 00:00:00
abstract：:Bacterial cell shapes are manifestations of programs carried out by multi-protein machines that synthesize and remodel the resilient peptidoglycan (PG) mesh and other polymers surrounding cells. GpsB protein is conserved in low-GC Gram-positive bacteria and is not essential in rod-shaped Bacillus subtilis, where it pl...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/mmi.12408
更新日期：2013-12-01 00:00:00
abstract：:The fitness of host-associated microbes depends on their ability to access nutrients in vivo. Identifying these mechanisms is significant for understanding how microbes have evolved to fill specific ecological niches within a host. Vibrio fischeri is a bioluminescent bacterium that colonizes and proliferates within th...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/mmi.14177
更新日期：2019-03-01 00:00:00
abstract：:Bacterial biofilms contain subpopulations of cells that are dormant and highly tolerant to antibiotics. While dormant, the bacteria must maintain the integrity of macromolecules required for resuscitation. Previously, we showed that hibernation promoting factor (HPF) is essential for protecting Pseudomonas aeruginosa ...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/mmi.14001
更新日期：2018-10-01 00:00:00
abstract：:The nucleotide sequence of a 2711bp DNA segment which contains the N-terminal coding sequence and the 5' flanking region of a crystal protein gene (bta) from Bacillus thuringiensis subsp. aizawai 7.29 has been determined. The coding region encodes an 824 amino-acid polypeptide corresponding to a carboxy-terminally tru...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1989.tb01812.x
更新日期：1989-02-01 00:00:00
abstract：:A strategy was developed to mutate and genetically identify exported proteins in Streptococcus pneumoniae. Vectors were created and used to screen pneumococcal DNA in Escherichia coli and S. pneumoniae for translational gene fusions to alkaline phosphatase (PhoA). Twenty five PhoA+ pneumococcal mutants were isolated a...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1993.tb01233.x
更新日期：1993-09-01 00:00:00
abstract：:Escherichia coli cells use two distinct sensory circuits during chemotaxis towards carbohydrates. One circuit requires the phosphoenolpyruvate-dependent phosphotransferase system (PTS) and is independent of any specific chemoreceptor, whereas the other uses a chemoreceptor-dependent sensory mechanism analogous to that...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.2003.03375.x
更新日期：2003-03-01 00:00:00
abstract：:The Bordetella pertussis wlb locus (wlbpe, formerly bpl) is required for the biosynthesis of a trisaccharide that, when attached to the B. pertussis lipopolysaccharide (LPS) core (band B), generates band A LPS. The equivalent loci in Bordetella bronchiseptica (wlbbr) and Bordetella parapertussis (wlbpa) were identifie...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1998.00878.x
更新日期：1998-07-01 00:00:00
abstract：:Regulation of DNA replication in Bacillus subtilis involves a post-initiation mechanism which is subject to control by the Stringent System, an essential regulatory network, mediated by the alarmone, ppGpp. In detailed studies using DNA-DNA hybridization procedures, we have now shown that, following the induction of t...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1995.tb02243.x
更新日期：1995-01-01 00:00:00
abstract：:The availability of nutrients is a major determinant for the timing of morphogenesis and antibiotic production in the soil-dwelling bacterium Streptomyces coelicolor. Here we show that N-acetylglucosamine transport, the first step of an important nutrient signalling cascade, is mediated by the NagE2 permease of the ph...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2009.07020.x
更新日期：2010-03-01 00:00:00
abstract：:We report a novel strategy for selecting mutations that mislocalize lipoproteins within the Escherichia coli cell envelope and describe the mutants obtained. A strain carrying a deletion of the chromosomal malE gene, coding for the periplasmic maltose-binding protein (MalE), cannot use maltose unless a wild-type copy ...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1999.01647.x
更新日期：1999-11-01 00:00:00
abstract：:The process of bacterial cell division involves the assembly of a complex of proteins at the site of septation that probably provides both the structural and the cytokinetic functions required for elaboration and closure of the septal annulus. During sporulation in Bacillus subtilis, this complex of proteins is modifi...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1998.00849.x
更新日期：1998-06-01 00:00:00
abstract：:Biofilm formation in Bacillus subtilis requires the differentiation of a subpopulation of cells responsible for the production of the extracellular matrix that structures the biofilm. Differentiation of matrix-producing cells depends, among other factors, on the FloT and YqfA proteins. These proteins are present exclu...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2012.08205.x
更新日期：2012-10-01 00:00:00
abstract：:Bacteria retain certain proteins at their cell envelopes by attaching them in a non-covalent manner to peptidoglycan, using specific protein domains, such as the prominent LysM (Lysin Motif) domain. More than 4000 (Pfam PF01476) proteins of both prokaryotes and eukaryotes have been found to contain one or more Lysin M...
journal_title：Molecular microbiology
pub_type： 杂志文章,评审
doi：10.1111/j.1365-2958.2008.06211.x
更新日期：2008-05-01 00:00:00
abstract：:Type IV secretion systems (T4SS) are utilized by a wide range of Gram negative bacteria to deliver protein and DNA substrates to recipient cells. The best characterized T4SS are the type IVA systems, which exhibit extensive similarity to the Agrobacterium VirB T4SS. In contrast, type IVB secretion systems share almost...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2006.05446.x
更新日期：2006-12-01 00:00:00
abstract：:The var multicopy gene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant antigens, which, through their ability to adhere to a variety of host receptors, are thought to be important virulence factors. The predominant expression of a single cytoadherent PfEMP1 type on an infected red ...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.2003.03505.x
更新日期：2003-06-01 00:00:00
abstract：:Bacteria attach to their appropriate environmental niche by using adhesins. To maximize their contact with the environment, adhesins are often present on the ends of long hairlike structures called pili. Recently, attention has focused on pili of Gram-positive bacteria because they may be vaccine candidates in importa...
journal_title：Molecular microbiology
pub_type： 杂志文章,评审
doi：10.1111/j.1365-2958.2006.05279.x
更新日期：2006-10-01 00:00:00
abstract：:Cyclic di-GMP (c-di-GMP) controls the transition between sessility and motility in many bacterial species. This regulation is achieved by a variety of mechanisms including alteration of transcription initiation and inhibition of flagellar function. How c-di-GMP inhibits the motility of Vibrio cholerae has not been det...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/mmi.12432
更新日期：2013-12-01 00:00:00
abstract：:We studied superoxide dismutases (SODs) in the encapsulated yeast Cryptococcus neoformans (Cn) variety gattii to analyse the role of mitochondrial MnSOD (SOD2) in fungal biology and virulence. SOD2 was cloned from a Cn cosmid library, sod2 mutant and sod2 + SOD2 reconstituted strains were constructed by homologous rec...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2005.04503.x
更新日期：2005-03-01 00:00:00
abstract：:We have shown previously that some particular mutations in bacteriophage Mu repressor, the frameshift vir mutations, made the protein very sensitive to the Escherichia coli ATP-dependent Clp protease. This enzyme is formed by the association between a protease subunit (ClpP) and an ATPase subunit. ClpA, the best chara...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1994.tb00387.x
更新日期：1994-03-01 00:00:00
abstract：:Glutaredoxins and thioredoxins are small heat-stable oxidoreductases that have been conserved throughout evolution. The yeast Saccharomyces cerevisiae contains two gene pairs encoding cytoplasmic glutaredoxins (GRX1, GRX2) and thioredoxins (TRX1, TRX2). We report here that the quadruple trx1 trx2 grx1 grx2 mutant is i...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.2000.01948.x
更新日期：2000-06-01 00:00:00
abstract：:The energy requirement for the second step in pullulanase secretion by the general secretory pathway was studied in Escherichia coli. In order to uncouple the two steps in the secretion pathway (across the cytoplasmic and outer membranes, respectively) and to facilitate kinetic analysis of secretion, a variant form of...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.1997.3451726.x
更新日期：1997-05-01 00:00:00
abstract：:We previously identified three well-dispersed mutations, E978-K, F989-L and D1009-R within the haemolysin A signal region, located at positions -46, -35 and -15, with respect to the C-terminus, respectively. Each mutation reduces the efficiency of secretion two- to threefold leaving 30-45% of the wild-type activity. W...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1994.tb00293.x
更新日期：1994-01-01 00:00:00
abstract：:Listeria monocytogenes grows in the cytosol of mammalian cells and spreads from cell to cell without exiting the intracellular milieu. During cell-cell spread, bacteria become transiently entrapped in double-membrane vacuoles. Escape from these vacuoles is mediated in part by a bacterial phospholipase C (PC-PLC), whos...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1046/j.1365-2958.2000.01708.x
更新日期：2000-01-01 00:00:00
abstract：:When fungi grow on plant or insect surfaces coated with wax polyesters that protect against pathogens, the fungi generally form aerial hyphae to contact the surfaces. Aerial structures such as hyphae and conidiophores are coated with hydrophobins, which are surface-active proteins involved in adhesion to hydrophobic s...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.2005.04803.x
更新日期：2005-09-01 00:00:00
abstract：:Two previously identified Bacillus subtilis DNA segments, dciA and dciB, whose transcripts accumulate very rapidly after induction of sporulation, were found in the same 6.2 kb transcription unit, now known as the dciA operon. Analysis of the sequence of the dciA operon showed that its putative products are homologous...
journal_title：Molecular microbiology
pub_type： 杂志文章
doi：10.1111/j.1365-2958.1991.tb00814.x
更新日期：1991-08-01 00:00:00
