Biology subjects

Abouelhadid, S.

Publications and source records attributed to Abouelhadid, S..

3 recordsLinked to original sources

bioRxiv2024

A platform for the recombinant production of Group A Streptococcus glycoconjugate vaccines

Strep A is a human-exclusive bacterial pathogen killing annually more than 500,000 patients, and no current licensed vaccine exists. Strep A bacteria are highly diverse, but all produce an essential, abundant, and conserved surface carbohydrate, the Group A Carbohydrate, which contains a rhamnose polysaccharide (RhaPS) backbone. RhaPS is a validated universal vaccine candidate in a glycoconjugate prepared by chemical conjugation of the native carbohydrate to a carrier protein. We engineered the Group A Carbohydratte biosynthesis pathway to enable recombinant production using the industry standard route to couple RhaPS to selected carrier proteins within E. coli cells. The structural integrity of the produced recombinant glycoconjugate vaccines was confirmed by NMR spectroscopy and mass spectrometry. Purified RhaPS glycoconjugates elicited carbohydrate-specific antibodies in mice and rabbits and bound to the surface of multiple Strep A strains of diverse M-types, confirming the recombinantly produced RhaPS glycoconjugates as valuable vaccine candidates.

microbiology↗

bioRxiv2021

Development of a novel glycoengineering platform for the rapid production of conjugate vaccines.

Antimicrobial resistance (AMR) is threatening the lives of millions worldwide. Antibiotics which once saved countless lives, are now failing, ushering in vaccines development as a current global imperative. Conjugate vaccines produced either by chemical synthesis or biologically in Escherichia coli cells, have been demonstrated to be safe and efficacious in protection against several deadly bacterial diseases. However, conjugate vaccines assembly and production have several shortcomings which hinders their wider availability. Here, we developed a tool, Mobile-element Assisted Glycoconjugation by Insertion on Chromosome, MAGIC, a novel method that overcomes the limitations of the current conjugate vaccine design method(s). We demonstrate at least 2-fold increase in glycoconjugate yield via MAGIC when compared to conventional bioconjugate method(s). Furthermore, the modularity of the MAGIC platform also allowed us to perform glycoengineering in genetically intractable bacterial species other than E. coli. The MAGIC system promises a rapid, robust and versatile method to develop vaccines against bacteria, especially AMR pathogens, and could be applied for biopreparedness.

microbiology↗

bioRxiv2019

N-linked glycans confer protein stability and modulate multidrug efflux pump assembly in Campylobacter jejuni

It is now apparent that nearly all bacteria species have at least a single glycosylation system, but the direct effect(s) of these protein post translational modifications are unresolved. In this study, we used the general N-linked glycosylation pathway from Campylobacter jejuni to investigate the biophysical roles of protein modification on the CmeABC multidrug efflux pump complex. The study reveals the multifunctional role of N-linked glycans in enhancing protein thermostability, stabilising protein complexes and the promotion of protein-protein interaction. Our findings demonstrate, for the first time, that regardless of glycan diversification among domains of life, N-linked glycans confer a common evolutionary intrinsic role.

biochemistry↗