Vaccination with a Protective Ipa Protein-Containing Nanoemulsion Differentially Alters the Transcriptomic Profiles of Young and Elderly Mice following Infection.

spp. are responsible for bacillary dysentery or shigellosis transmitted via the fecal-oral route, causing significant morbidity and mortality, especially among vulnerable populations. There are currently no licensed vaccines.

Development of a nano-emulsion based multivalent protein subunit vaccine against .

(Pa) is an opportunistic bacterial pathogen responsible for severe hospital acquired infections in immunocompromised and elderly individuals. Emergence of increasingly drug resistant strains and the absence of a broad-spectrum prophylactic vaccine against both T3SA (type III secretion apparatus) and ExlA/T3SA Pa strains worsen the situation in a post-pandemic world. Thus, we formulated a candidate subunit vaccine (called ExlA/L-PaF/BECC/ME) against both Pa types.

The L-DBF vaccine cross protects mice against different serotypes after prior exposure to the pathogen.

Shigellosis is endemic to low- and middle-income regions of the world where children are especially vulnerable. In many cases, there are pre-existing antibodies in the local population and the effect of prior exposure should be considered in the development and testing of vaccines against infection. Our study shows that L-DBF-induced immune responses are not adversely affected by prior exposure to this pathogen.

Immunogenicity and protective efficacy of nanoparticle formulations of L-SseB against infection.

, a Gram-negative pathogen, has over 2500 serovars that infect a wide range of hosts. In humans, causes typhoid or gastroenteritis and is a major public health concern. In this study, SseB (the tip protein of the pathogenicity island 2 type III secretion system) was fused with the LTA1 subunit of labile-toxin from enterotoxigenic to make the self-adjuvanting antigen L-SseB.

Composition and Biophysical Properties of the Sorting Platform Pods in the Type III Secretion System.

, causative agent of bacillary dysentery (shigellosis), uses a type III secretion system (T3SS) as its primary virulence factor. The T3SS injectisome delivers effector proteins into host cells to promote entry and create an important intracellular niche. The injectisome's cytoplasmic sorting platform (SP) is a critical assembly that contributes to substrate selection and energizing secretion.

The Type III Secretion System: An Overview from Top to Bottom.

comprises four species of human-restricted pathogens causing bacillary dysentery. While possesses multiple genetic loci contributing to virulence, a type III secretion system (T3SS) is its primary virulence factor. The T3SS nanomachine consists of four major assemblies: the cytoplasmic sorting platform; the envelope-spanning core/basal body; an exposed needle; and a needle-associated tip complex with associated translocon that is inserted into host cell membranes.

Development of a Broadly Protective, Self-Adjuvanting Subunit Vaccine to Prevent Infections by .

Infections caused by the opportunistic pathogen can be difficult to treat due to innate and acquired antibiotic resistance and this is exacerbated by the emergence of multi-drug resistant strains. Unfortunately, no licensed vaccine yet exists to prevent infections. Here we describe a novel subunit vaccine that targets the type III secretion system (T3SS).

The Structures of SctK and SctD from Pseudomonas aeruginosa Reveal the Interface of the Type III Secretion System Basal Body and Sorting Platform.

Many Gram-negative bacterial pathogens use type III secretion systems (T3SS) to inject proteins into eukaryotic cells to subvert normal cellular functions. The T3SS apparatus (injectisome) shares a common architecture in all systems studied thus far, comprising three major components - the cytoplasmic sorting platform, envelope-spanning basal body and external needle with tip complex. The sorting platform consists of an ATPase (SctN) connected to "pods" (SctQ) having six-fold symmetry via radial spokes (SctL).

¹H, ¹⁵N, and ¹³C backbone resonance assignments for the Yersinia protein tyrosine phosphatase YopH.

YopH is a protein tyrosine phosphatase that functions as a required virulence factor in Yersinia. Here we report the backbone resonance assignments for a point mutant of the C-terminal catalytic domain of YopH.

Conformational motions regulate phosphoryl transfer in related protein tyrosine phosphatases.

Many studies have implicated a role for conformational motions during the catalytic cycle, acting to optimize the binding pocket or facilitate product release, but a more intimate role in the chemical reaction has not been described. We address this by monitoring active-site loop motion in two protein tyrosine phosphatases (PTPs) using nuclear magnetic resonance spectroscopy. The PTPs, YopH and PTP1B, have very different catalytic rates; however, we find in both that the active-site loop closes to its catalytically competent position at rates that mirror the phosphotyrosine cleavage kinetics.

Reengineering rate-limiting, millisecond enzyme motions by introduction of an unnatural amino acid.

Rate-limiting millisecond motions in wild-type (WT) Ribonuclease A (RNase A) are modulated by histidine 48. Here, we incorporate an unnatural amino acid, thia-methylimidazole, at this site (H48C-4MI) to investigate the effects of a single residue on protein motions over multiple timescales and on enzyme catalytic turnover. Molecular dynamics simulations reveal that H48C-4MI retains some crucial WT-like hydrogen bonding interactions but the extent of protein-wide correlated motions in the nanosecond regime is decreased relative to WT.