Sodium Dodecyl Sulfate Analogs as a Potential Molecular Biology Reagent.

In this study, we review the properties of three anionic detergents, sodium dodecyl sulfate (SDS), Sarkosyl, and sodium lauroylglutamate (SLG), as they play a critical role in molecular biology research. SDS is widely used in electrophoresis and cell lysis for proteomics. Sarkosyl and, more frequently, SDS are used for the characterization of neuropathological protein fibrils and the solubilization of proteins.

Successful removal of an accidentally swallowed press-through package sheet using a detachable snare: A case report.

Accidental swallowing of press-through package (PTP) sheets that could cause esophageal perforation is commonly encountered in emergency departments requiring early detection and removal. We report a case in which an accidentally swallowed PTP sheet was removed from the esophagus using a detachable snare after usual endoscopic methods proved ineffective. A Japanese woman in her 60s visited the emergency department with a persistent sore throat.

Structure Analysis of Proteins and Peptides by Difference Circular Dichroism Spectroscopy.

Difference circular dichroism (CD) spectroscopy was used here to characterize changes in structure of flexible peptides upon altering their environments. Environmental changes were introduced by binding to a large target structure, temperature shift (or concentration increase) or so-called membrane-mimicking solvents. The first case involved binding of a largely disordered peptide to its target structure associated with chromatin remodeling, leading to a transition into a highly helical structure.

Survival Rate and Shunt Infection Incidence Following Gastrostomy in Adult Patients with an Existing Ventriculoperitoneal Shunt.

Ventriculoperitoneal shunts (VPS) and gastrostomies are frequently provided in daily practice. This study investigated the incidence of VPS infection and the survival rate among adult patients who underwent gastrostomy at least 1 month after VPS placement. This single-center retrospective cohort study was conducted among patients with a VPS, who underwent a gastrostomy.

Procedure-Related Complications and Survival after Gastrostomy: Results from a Japanese Cohort.

Introduction: In 2010, a large-scale multi-institutional study in Japan showed a good prognosis for percutaneous endoscopic gastrostomy (PEG). However, the function and efficacy of PEG are not fully understood by patients, families, and health-care professionals; thus, the number of PEG treatments in Japan has declined. Therefore, we aimed to investigate the safety of the PEG procedure and subsequent survival after PEG.

Protein Solvent Interaction: Transition of Protein-solvent Interaction Concept from Basic Research into Solvent Manipulation of Chromatography.

Previously, we have reviewed in this journal (Arakawa, T., Kita, Y., Curr.

Capto MMC mixed-mode chromatography of murine and rabbit antibodies.

Murine antibodies have weak affinity for Protein-A. Here, we have tested binding of murine monoclonal antibody (mAb) to Protein-A or Protein-A/Protein-G mixture under salting-out conditions. The addition of ammonium sulfate to HEK conditioned medium (CM) expressing murine mAb resulted in complete binding, leading to its elution by low pH or neutral arginine solution.

SUMO3 modification accelerates the aggregation of ALS-linked SOD1 mutants.

Mutations in superoxide dismutase 1 (SOD1) are a major cause of familial amyotrophic lateral sclerosis (ALS), whereby the mutant proteins misfold and aggregate to form intracellular inclusions. We report that both small ubiquitin-like modifier (SUMO) 1 and SUMO2/3 modify ALS-linked SOD1 mutant proteins at lysine 75 in a motoneuronal cell line, the cell type affected in ALS. In these cells, SUMO1 modification occurred on both lysine 75 and lysine 9 of SOD1, and modification of ALS-linked SOD1 mutant proteins by SUMO3, rather than by SUMO1, significantly increased the stability of the proteins and accelerated intracellular aggregate formation.

Multi-faceted arginine: mechanism of the effects of arginine on protein.

Arginine is widely used in such applications as protein refolding, solubilization of proteins and small molecules, protein and small molecule formulation, column chromatography and viral inactivation as summarized in this review. What makes arginine effective in these applications is largely based on its ability to suppress protein-protein interactions and protein-surface interactions. The mechanism of these widespread effects of arginine on proteins can be explained at least in part from its unique interactions with the protein surface.

Structural characteristics of short peptides in solution.

Short peptides are important biopharmaceuticals as agonistic or antagonistic ligands, aggregation inhibitors, and vaccines, as well as in many other applications. They behave differently from globular proteins in solution. Many short peptides are unstructured and tend to aggregate and undergo structural transition in response to changes in solvent environment, including pH, temperature, ionic strength, presence of organic solvents or surfactants, and exposure to lipid membranes.

Inactive C8A‑humanin analog is as stable as a potent S14G‑humanin analog.

We have previously shown that the structural stability of humanin (HN), a neuroprotective peptide ligand, is one of the attributes to the observed activity differences between HN analogs. It has been observed that the activity increased consecutively in the S7A‑HN analog, the parent HN and the S14G‑HN analog, consistent with the increased stability observed in that order. In the present study, the structure and stability of another inactive analog, C8A‑HN, was measured, which has been revealed to have no neuroprotective activity similar to that of the S7A‑HN analog and hence may have compromised stability.

Interactions of formulation excipients with proteins in solution and in the dried state.

A variety of excipients are used to stabilize proteins, suppress protein aggregation, reduce surface adsorption, or to simply provide physiological osmolality. The stabilizers encompass a wide variety of molecules including sugars, salts, polymers, surfactants, and amino acids, in particular arginine. The effects of these excipients on protein stability in solution are mainly caused by their interaction with the protein and the container surface, and most importantly with water.

The biological activity of Humanin analogs correlates with structure stabilities in solution.

A single mutation has resulted in large differences in neuroprotective activity of a 24 amino acid Humanin (HN). A mutation of Ser7Ala (S7A-HN) resulted in loss of activity, while a mutation of Ser14Gly (S14G-HN) resulted in about 1000-fold increase. The mechanism of the effects conferred by these mutations have been totally unclear, although our recent structure analysis suggested a possibility of the effect of mutation on the structure stability.

Structure of three Humanin peptides with different activities upon interaction with liposome.

We have recently shown that a 24 amino acid Humanin (HN) adopts an anti-parallel β-sheet structure in the presence of a negatively charged 1,2-dioleoyl-sn-glycero-3-phosphoglycerol (DOPG) and suggested a possibility that it interacts with lipid membranes and thereby exerts neuroprotective effects through the target cell surface receptors or the intracellular signaling molecules following membrane interaction events. The structures of two HN analogs, having either a S7A mutation or a S14G mutation, were examined under the identical conditions, as the S7A analog is inactive and the S14G analog is 1000-fold more active than the wild type HN. These analogs showed a secondary structure indistinguishable from the structure of HN in the presence of DOPG liposome, while unrelated peptides were disordered with and without DOPG.

Chemical and pharmacological chaperones: application for recombinant protein production and protein folding diseases.

Since protein function depends on folding, successful development of active pharmaceutical proteins requires in vitro production of functional, properly folded proteins. In vitro protein folding and hence production can be assisted by co-solvents, including osmolytes and arginine. Osmolytes accumulate in the cytoplasm to raise the osmotic pressure against environmental water stresses, resulting in stabilization of proteins.

Structure changes of natively disordered Humanin in the presence of lipid.

While neuroprotective activities of Humanin peptides have been clearly demonstrated, the functional mechanism has not been fully understood. Humanin and a majority of Humanin analogs showed a disordered structure at low peptide concentrations and aggregation at higher concentrations in aqueous solution at pH 7.0.

Stabilizing and destabilizing effects of arginine on deoxyribonucleic acid.

Aqueous arginine solution now finds a wide range of applications in biotechnology fields, including protein refolding, chromatography and virus inactivation. While progress has been made for mechanistic understanding of the effects of arginine on proteins, we have little understanding on how arginine inactivates viruses. One of the viral components is nucleic acid.

MEP HyperCel chromatography II: binding, washing and elution.

Binding, washing and elution conditions for MEP HyperCel chromatography were examined using two conditioned media (CM) containing monoclonal antibodies (humanized IgG1) and bovine serum albumin (BSA). Monoclonal antibodies derived from mammalian expression system bound to the column without pretreatment, although a majority of contaminating proteins present in the CM also showed binding. Inorganic salts, ethanol and glycerol were ineffective in eluting proteins under the conditions examined, suggesting that electrostatic or hydrophobic interactions are not a major factor for antibody binding to the MEP resin.

Stress-free chromatography: IEC and HIC.

Ion exchange chromatography (IEC) poses stresses on proteins in both binding and elution steps. Proteins often bind to the column with high affinity, resulting in concentration of the protein upon binding. Elution often requires high salt concentration, leading to high protein concentration with high salt concentration.

Stress-free chromatography: affinity chromatography.

A number of approaches are available in minimizing aggregation of the final protein products. This chapter describes one such approach, i.e.

Short neuroprotective peptides, ADNF9 and NAP, are structurally disordered and monomeric in PBS.

Activity-dependent neurotrophic factor 9 (ADNF9) and NAP are nine and eight amino acid peptides, which exhibit neuroprotective activity at femtomolar concentrations against cell toxic agents. We have here characterized their structures and interactions with dodecylphosphocholine (DPC) in phosphate-buffered saline (PBS). Circular dichroism analysis showed that ADNF9 and NAP are structurally disordered in PBS independent of peptide concentration and temperature, but appear to assume different secondary structure at increasing temperature.

Active form of neuroprotective Humanin, HN, and inactive analog, S7A-HN, are monomeric and disordered in aqueous phosphate solution at pH 6.0; No correlation of solution structure with activity.

A novel neuroprotective peptide, Humanin (HN), has a strong tendency to aggregate in phosphate-buffered saline. Here we attempted to reduce aggregation employing an aqueous phosphate solution, without NaCl, at pH 6.0 and low peptide concentrations wherever possible.

MEP chromatography of antibody and Fc-fusion protein using aqueous arginine solution.

MEP HyperCel resin, one of the Protein-A mimetic columns, is designed to bind antibodies at physiological pH and elutes the bound antibodies at mildly acidic pH. We have tested aqueous arginine solution for washing and elution of the resin. To our surprise, bound antibody and Fc-fusion protein eluted at pH 7.