Streamlined Multi-Attribute Assessment of an Array of Clinical-Stage Antibodies: Relationship Between Degradation and Stability.

Clinical antibodies are an important class of drugs for the treatment of both chronic and acute diseases. Their manufacturability is subject to evaluation to ensure product quality and efficacy. One critical quality attribute is deamidation, a non-enzymatic process that is observed to occur during thermal stress, at low or high pH, or a combination thereof.

PSGL-1 Blockade Induces Classical Activation of Human Tumor-associated Macrophages.

Unlabelled: The immune suppressive microenvironment is a major culprit for difficult-to-treat solid cancers. Particularly, inhibitory tumor-associated macrophages (TAM) define the resistant nature of the tumor milieu. To define tumor-enabling mechanisms of TAMs, we analyzed molecular clinical datasets correlating cell surface receptors with the TAM infiltrate.

LP mutation on heavy chain stabilizes IgG under acidic conditions.

IgG, a common type of therapeutic antibody, is less stable during manufacturing processes compared with IgG. Aggregation and fragmentation are the two main challenges. Here, we report instability of the heavy chain (HC) C-terminal region under acidic conditions, which leads to cleavage and aggregation.

Point mutations at the catalytic site of PCSK9 inhibit folding, autoprocessing, and interaction with the LDL receptor.

Circulating low-density lipoprotein cholesterol (LDLc) is regulated by membrane-bound LDL receptor (LDLr). Upon LDLc and LDLr interaction the complex is internalized by the cell, leading to LDLc degradation and LDLr recycling back to the cell surface. The proprotein convertase subtilisin/kexin type 9 (PCSK9) protein regulates this cycling.

A small molecule that binds and inhibits the ETV1 transcription factor oncoprotein.

Members of the ETS transcription factor family have been implicated in several cancers, where they are often dysregulated by genomic derangement. ETS variant 1 (ETV1) is an ETS factor gene that undergoes chromosomal translocation in prostate cancers and Ewing sarcomas, amplification in melanomas, and lineage dysregulation in gastrointestinal stromal tumors. Pharmacologic perturbation of ETV1 would be appealing in these cancers; however, oncogenic transcription factors are often deemed "undruggable" by conventional methods.

N-glycosylation of enhanced aromatic sequons to increase glycoprotein stability.

N-glycosylation can increase the rate of protein folding, enhance thermodynamic stability, and slow protein unfolding; however, the molecular basis for these effects is incompletely understood. Without clear engineering guidelines, attempts to use N-glycosylation as an approach for stabilizing proteins have resulted in unpredictable energetic consequences. Here, we review the recent development of three "enhanced aromatic sequons," which appear to facilitate stabilizing native-state interactions between Phe, Asn-GlcNAc and Thr when placed in an appropriate reverse turn context.

Amyloid-β forms fibrils by nucleated conformational conversion of oligomers.

Amyloid-β amyloidogenesis is reported to occur via a nucleated polymerization mechanism. If this is true, the energetically unfavorable oligomeric nucleus should be very hard to detect. However, many laboratories have detected early nonfibrillar amyloid-β oligomers without observing amyloid fibrils, suggesting that a mechanistic revision may be needed.

Protein native-state stabilization by placing aromatic side chains in N-glycosylated reverse turns.

N-glycosylation of eukaryotic proteins helps them fold and traverse the cellular secretory pathway and can increase their stability, although the molecular basis for stabilization is poorly understood. Glycosylation of proteins at naïve sites (ones that normally are not glycosylated) could be useful for therapeutic and research applications but currently results in unpredictable changes to protein stability. We show that placing a phenylalanine residue two or three positions before a glycosylated asparagine in distinct reverse turns facilitates stabilizing interactions between the aromatic side chain and the first N-acetylglucosamine of the glycan.

The core trisaccharide of an N-linked glycoprotein intrinsically accelerates folding and enhances stability.

The folding energetics of the mono-N-glycosylated adhesion domain of the human immune cell receptor cluster of differentiation 2 (hCD2ad) were studied systematically to understand the influence of the N-glycan on the folding energy landscape. Fully elaborated N-glycan structures accelerate folding by 4-fold and stabilize the beta-sandwich structure by 3.1 kcal/mol, relative to the nonglycosylated protein.