Silver(I) complexes with aza-oxa macrocyclic Schiff bases L (L = 1,5-diaza-2,4:7,8:16,17-tribenzo-9,15-dioxa-cyclooctadeca-1,5-dien) were prepared by the reaction of corresponding macrocycle four different silver salts (AgX; X ClO4, PF6, SbF6 and BF4). In all compounds, ions are exo-coordinated two neighboring ligand molecules in linear T-shaped geometries. Such a coordination mode results form...

A supramolecular system in which the concentration of a molecule is buffered over several orders of magnitude is presented. Molecular buffering is achieved as a result of competition in a ring-chain equilibrium of multivalent ureidopyrimidinone monomers and a monovalent naphthyridine molecule which acts as an end-capper. While we previously only considered divalent ureidopyrimidinone monomers w...

We study a minimal extension of the wormlike chain model to describe polypeptides having a-helical secondary structure. In this model the presence or absence of secondary structure enters as a scalar variable that controls the local chain bending modulus. Using this model we compute the extensional compliance of an a-helix under tensile stress, the bending compliance of the molecule under exter...

GGAs, a class of monomeric clathrin adaptors, are involved in the sorting of cargo at the trans-Golgi network of eukaryotic cells. They are modular structures consisting of the VHS, the GAT, hinge, and GAE domains, which have been shown to interact directly with cargo, ARF, clathrin, and accessory proteins, respectively. Previous studies have shown that GGAs interact with clathrin both in solut...

Polyreactive antibodies (Abs) constitute a major proportion of the early Ab repertoire and are an important component of the natural defense mechanisms against infections. They are primarily immunoglobulin M (IgM) and bind a variety of structurally dissimilar self and exogenous antigens (Ags) with moderate affinity. We analyzed the contribution of Ig polyvalency and of heavy (H) and light (L) c...

2-Hydroxy-N-{2-[2-hydroxyethyl)amino]ethyl}benzamide (L¹H₃) and 2-hydroxy-N-{2-[2-hydroxybutyl)amino]ethyl}benzamide (L²H₃) ligands coordinate to copper ions to give anionic metalloligands, L¹Cu⁻ and L²Cu⁻, after deprotonation of their amide, alcohol and phenol functions. In presence of ancillary ligands as diketones, these metalloligands react with lanthanide salts to yield tetranuclear [Cu-Ln...

Abnormal IgA1 half-molecules consisting of one heavy and one light chain were found in a patient (N.N.) with typical multiple myeloma. The serum and the urine of this patient contained both 7.0S and 3.9S IgA myeloma proteins. The IgA half-molecules (3.9S) were found to have a molecular weight of 59,000 daltons and were composed of one alpha1 chain of about 40,000 daltons and one light chain of ...

Immunological studies of rat skin collagen were carried out with a sensitive and quantitative radioimmunoassay. Hyperimmune rabbit antisera to rat skin collagen and isolated alpha2 chains were used. Iodine-labeled alpha chains and CNBr-produced peptides served as test antigens, and native collagen, alpha chains, and CNBr peptides were employed as inhibitors in the assay. The alpha1 and alpha2 c...

Muscle contraction is powered by the interaction of the molecular motor myosin with actin. With new techniques for single molecule manipulation and fluorescence detection, it is now possible to correlate, within the same molecule and in real time, conformational states and mechanical function of myosin. A spot-confocal microscope, capable of detecting single fluorophore polarization, was develo...