Protein- and Cell-Resistance of Zwitterionic Peptide-Based Self-Assembled Monolayers: Anti-Biofouling Tests and Surface Force Analysis.

Peptide-based self-assembled monolayers (peptide-SAMs) with specific zwitterionic amino acid sequences express an anti-biofouling property. In this work, we performed protein adsorption and cell adhesion tests using peptide-SAMs with repeating units of various zwitterionic pairs of amino acids (EK, DK, ER, and DR). The SAMs with the repeating units of EK and DK (EK and DK SAMs) manifested excellent bioinertness, whereas the SAMs with the repeating units of ER and DR (ER and DR SAMs) adhered proteins and cells.

Effect of the Molecular Weight of Poly(2-methoxyethyl acrylate) on Interfacial Structure and Blood Compatibility.

The blood-compatible polymer poly(2-methoxyethyl acrylate) (PMEA) is composed of nanometer-scale interfacial structures because of the phase separation of the polymer and water at the PMEA/phosphate-buffered saline (PBS) interface. We synthesized PMEA with four different molecular weights (19, 30, 44, and 183 kg/mol) to investigate the effect of the molecular weight on the interfacial structures and blood compatibility. The amounts of intermediate water and fibrinogen adsorption were not affected by the molecular weight of PMEA.

Combined sodium ion sensitivity in agonist binding and internalization of vasopressin V1b receptors.

Reducing Na(+) in the extracellular environment may lead to two beneficial effects for increasing agonist binding to cell surface G-protein coupled receptors (GPCRs): reduction of Na(+)-mediated binding block and reduce of receptor internalization. However, such combined effects have not been explored. We used Chinese Hamster Ovary cells expressing vasopressin V1b receptors as a model to explore Na(+) sensitivity in agonist binding and receptor internalization.

Subcellular localization and internalization of the vasopressin V1B receptor.

Only limited information is available on agonist-dependent changes in the subcellular localization of vasopressin V1B receptors. Our radioligand binding study of membrane preparations and intact cells revealed that a large fraction of the V1B receptor is located in the cytoplasm in unstimulated CHO cells, which is in contrast to the plasma membrane localization of the V1A and V2 receptors. Moreover, when the affinity of radiolabeled arginine-vasopressin ([3H]AVP) was compared between membrane preparations and intact cells, the affinity of [3H]AVP to the cell surface V1B receptors, but not the V1A receptors, was significantly reduced.

Pharmacological lineage analysis revealed the binding affinity of broad-spectrum substance P antagonists to receptors for gonadotropin-releasing peptide.

A group of synthetic substance P (SP) antagonists, such as [Arg(6),D-Trp(7,9),N(Me)Phe(8)]-substance P(6-11) and [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]-substance P, bind to a range of distinct G-protein-coupled receptor (GPCR) family members, including V1a vasopressin receptors, and they competitively inhibit agonist binding. This extended accessibility enabled us to identify a GPCR subset with a partially conserved binding site structure. By combining pharmacological data and amino acid sequence homology matrices, a pharmacological lineage of GPCRs that are sensitive to these two SP antagonists was constructed.