Soluble variants of human recombinant glutaminyl cyclase

Preliminary screening of new biomarkers for sepsis using bioinformatics and experimental validation

BACKGROUND

The morbidity and mortality of sepsis remain high, and so far specific diagnostic and therapeutic means are lacking.

OBJECTIVE

To screen novel biomarkers for sepsis.

METHODS

Raw sepsis data were downloaded from the Chinese National Genebank (CNGBdb) and screened for differentially expressed RNAs. Key genes with predictive value were identified through weighted correlation network analysis (WGCNA) and meta-analysis and survival analysis using multiple public databases. Core genes were analyzed for functional enrichment using Gene Set Enrichment Analysis(GSEA). The core genes were localized using single-cell sequencing. qPCR was used to validate the core genes.

RESULTS

Differential analysis yielded a total of 5125 mRNA. WGCNA identified 5 modules and screened 3 core genes (S100A11, QPCT, and IFITM2). The prognosis of sepsis patients was strongly linked to S100A11, QPCT, and IFITM2 based on meta-analysis and survival analysis(P < 0.05).GSEA analysis showed that S100A11, QPCT, and IFITM2 were significantly enriched in ribosome-related pathways. S100A11 and QPCT were widely distributed in all immune cells, and QPCT was mainly localized in the macrophage cell lineage. In the sepsis group, the qPCR results showed that S100A11, QPCT, and IFITM2 expression levels were significantly higher in the sepsis group(P < 0.05).

CONCLUSION

In this study, S100A11, QPCT, and IFITM2 were screened as new potential biomarkers for sepsis. Validated by bioinformatics analysis and qPCR, these genes are closely associated with the prognosis of sepsis patients and have potential as diagnostic and therapeutic targets.

High yield expression and purification of full-length Neurotensin with pyroglutamate modification

Neurotensin (NT) is a 13-residue endogenous peptide found in mammals, with neurotransmission and hormonal roles in the central nervous system and gastrointestinal tract, respectively. The first residue of NT is a pyroglutamate (pGlu) that makes the expression and purification of large amounts of NT with native modification challenging. Here, we describe a simple and efficient procedure for expression and purification of large amounts of NT based on using the small ubiquitin-like modifier (SUMO) as a fusion partner and subsequent enzymatic conversion of the N-terminal glutamine to pGlu. Yields of 13 mg/L and 8 mg/L of pure peptide were obtained from expression in rich and minimal media, respectively. The method is adaptable to expression and purification of proteins and peptides with pGlu modification in a wide range of eukaryotic and prokaryotic expression hosts.

The soluble Y115E-Y117E variant of human glutaminyl cyclase is a valid target for X-ray and NMR screening of inhibitors against Alzheimer disease

Recent developments in molecular pathology and genetics have allowed the identification of human glutaminyl cyclase (hQC) among the abnormal proteins involved in many neurodegenerative disorders. Difficulties in obtaining large quantities of pure protein may limit the use of crystallographic screening for drug development on this target. Site-directed mutagenesis experiments have led to the identification of some solvent-exposed residues that are absolutely critical to achieve increased solubility and to avoid precipitation of the enzyme in inclusion bodies when expressed in Escherichia coli. The designed variant Y115E-Y117E has been found to be able to provide large amounts of monodisperse, pure hQC from an E. coli expression system. To validate the use of the artificial construct as a target for large-scale X-ray and NMR screening campaigns in the search for new inhibitors of hQC, the X-ray crystal structures of the hQC Y115E-Y117E variant and of its adduct with the inhibitor PBD-150 were determined.