The function of a protein generally depends on adoption specific folding pattern, which in turn is determined by the side chain sequence along polypeptide backbone. Here we show that sequence-encoded structural information peptides derived from yeast transcriptional activator GCN4 can be used to prepare hybrid α/β-peptide foldamers adopt helix bundle quaternary structures. Crystal structures two α/β-peptides are reported with detailed comparison α-peptides analogous sequence. There...

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

The extent to which polypeptide conformation depends on side-chain composition and sequence has been widely studied, but less is known about the importance of maintaining an α-amino acid backbone. Here, we examine a series peptides with backbones that feature different repeating patterns α- β-amino residues invariant sequence. In pure α-backbone, this corresponds previously studied peptide GCN4-pLI, forms very stable four-helix bundle quaternary structure. Physical characterization in...

Carbohydrate-aromatic interactions mediate many biological processes. However, the structure-energy relationships underpinning direct carbohydrate-aromatic packing in aqueous solution have been difficult to assess experimentally and remain elusive. Here, we determine structures folding energetics of chemically synthesized glycoproteins quantify contributions hydrophobic effect CH-π proteins. We find that contributes significantly protein-carbohydrate interactions. Interactions between...

The development of unnatural oligomers that adopt predictable secondary structures has led to increased interest in expanding the conformational repertoire foldamers include discrete, cooperatively folded tertiary and quaternary structures. Here we report first examples heterogeneous structure: stable tetrameric helix bundles incorporating both α-peptides α/β-peptide foldamers. results suggest hydrophobic interactions core bundle contribute stability assembly, as do cyclic β-amino acid...

Asparagine glycosylation is one of the most common and important post-translational modifications proteins in eukaryotic cells. N-Glycosylation occurs when a triantennary glycan precursor transferred en bloc to nascent polypeptide (harboring N−X−T/S sequon) as peptide cotranslationally translocated into endoplasmic reticulum (ER). In addition facilitating binding interactions with components ER proteostasis network, N-glycans can also have intrinsic effects on protein folding by directly...

Cotranslational N-glycosylation can accelerate protein folding, slow unfolding, and increase stability, but the molecular basis for these energetic effects is incompletely understood. of proteins at naïve sites could be a useful strategy stabilizing in therapeutic research applications, without engineering guidelines, often results unpredictable changes to energetics. We recently introduced enhanced aromatic sequon as family portable structural motifs that are stabilized upon glycosylation...

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

PEGylation of protein side chains has been used for more than 30 years to enhance the pharmacokinetic properties drugs. However, there are no structure- or sequence-based guidelines selecting sites that provide optimal PEG-based enhancement with minimal losses biological activity. We hypothesize globally characterized by ability PEG oligomer increase conformational stability; however, current understanding how influences stability proteins is incomplete. Here we use WW domain human Pin 1...

We report high-resolution crystal structures of six new α/β-peptide foldamers that have a regular α-residue/α-residue/β-residue (ααβ) backbone repeat pattern. All these were crystallized from aqueous solution, and all display four-helix bundle quaternary structure in the crystalline state. These oligomers are based on well-studied 33-residue α-peptide GCN4-pLI, which is an engineered derivative dimerization domain GCN4, yeast transcription factor. GCN4-pLI forms stable tetramer solution...

PEGylation, or addition of poly(ethylene glycol) chains to proteins, is widely used improve delivery in pharmaceutical applications. Recent studies suggest that stabilization a protein by PEG, and hence its proteolytic degradability, sequence-dependent requires only short PEG chains. Here we connect directly the structural dynamics chain. We measured stability human Pin1 WW domain with PEG-4 at asparagine 19 for full mutant cycle two positions thought influence PEG-protein interaction:...

Macrocyclization or stapling is an important strategy for increasing the conformational stability and target-binding affinity of peptides proteins, especially in therapeutic contexts. Atomistic simulations such stapled proteins could help rationalize existing experimental data provide predictive tools design new proteins. Standard approaches exist incorporating nonstandard amino acids functional groups into force fields required MD have been used context more than a decade. However,...

Backbone thioester exchange is used to explore a fundamental type of protein–foldamer packing motif, the association an α helix and α/β-peptide foldameric helix, which analogous antiparallel coiled-coil tertiary structure in pure α-residue backbone. Side-chain preferences at this chimeric interface are comparable those that determine pairing propensities among helices. Detailed facts importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but not...

Protein PEGylation is an effective method for reducing the proteolytic susceptibility, aggregation propensity, and immunogenicity of protein drugs. These pharmacokinetic challenges are fundamentally related to conformational stability, become much worse proteins that populate unfolded state under ambient conditions. If consistently led increased its beneficial effects could be extended enhanced. However, impact on stability currently unpredictable. Here we show appending a short PEG oligomer...

Familial amyloidosis of Finnish type (FAF), or gelsolin amyloidosis, is a systemic amyloid disease caused by mutation (D187N/Y) in domain 2 human plasma gelsolin, resulting misfolding within the secretory pathway. When D187N/Y passes through Golgi, furin endoproteolysis occurs as consequence abnormal conformations that enable to bind and cleave, secretion 68 kDa C-terminal fragment (amino acids 173−755, C68). The C68 cleaved upon from cell membrane 1 matrix metalloprotease (MT1-MMP),...

Anions have long been known to engage in stabilizing interactions with electron-deficient arenes. However, the precise nature and energetic contribution of anion-π protein stability remains a subject debate. Here, we show that placing negatively charged Asp close proximity electron-rich Phe reverse turn within WW domain results favorable interaction increases conformational by -1.3 kcal/mol.

Site-specific PEGylation is an important strategy for enhancing the pharmacokinetic properties of protein drugs, and has been enabled by recent development many chemoselective reactions side-chain modification. However, impact these different conjugation strategies on PEG-protein conjugates poorly understood. Here we show that ability PEG to enhance conformational stability depends strongly identity linker, with most stabilizing linkers involving planar polar groups near peptide backbone. We...

Cooperative catalytic systems are making significant advances in modern organic synthesis due to the potential combine multiple cycles or enable enzyme-like proximity effects. We report rational design of a bifunctional helical peptide catalyst that displays an imidazolidinone close thiourea binding site and enables proximity-enhanced reactivity selectivity. The structure both reactants shown be essential for enhanced Diels–Alder indole alkylation reactions, up 28 000 turnovers achieved. A...

Antibiotic resistance is an escalating global health threat. Due to their diverse mechanisms of action and evasion traditional mechanisms, peptides hold promise as future antibiotics. Their ability disrupt bacterial membranes presents a potential strategy combat drug-resistant infections address the increasing need for effective antimicrobial treatments. Amphipathic α-helical possess distinctive molecular structure with both charged/hydrophilic hydrophobic regions that interact cell...

The bulky dehydroamino acids dehydrovaline (ΔVal) and dehydroethylnorvaline (ΔEnv) can be inserted into the turn regions of β-hairpin peptides without altering their secondary structures. These residues increase proteolytic stability, with ΔVal at (i + 1) position having most substantial impact. Additionally, a acid paired d-amino (i.e., d-Pro) to synergistically enhance resistance proteolysis. A link between stability peptide structure is established by finding that stabilized...