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Cadherins are calcium-binding proteins which are responsible for cell-cell adhesion in biological systems. Cadherins are involved in embryo compaction, neurite growth, cellular differentiation and formation of biological barriers (i.e., intestinal and blood brain barriers). A short linear peptide, LRAHAVDVNG-NH2 (Peptide 1), which contains His-Ala-Val sequence and is derived from the N-cadherin sequence has been shown to inhibit embryo compaction and neurite growth; this is caused by inhibition of the cadherin-cadherin interactions. Peptide 1 was synthesized and its solution conformation was determined by proton nuclear magnetic resonance, circular dichroism and molecular dynamics simulations. These studies indicated that the peptide has an extended structure from residue Leu1 to Asp7, possibly a beta-sheet structure, followed by a beta-turn from Asp7 to Gly10. The X-ray crystal structure of a sequence similar to that of peptide 1 in hemagglutinin indicated that it also has a beta-sheet structure around the HAV sequence, followed by a beta-turn.

Cadherins are calcium dependent glycoproteins involved in homophilic cell-cell adhesion. To further elucidate the interaction between cadherins we have developed an immobilized peptide ELISA to quickly scan the extracellular domains of E-cadherin. Peptides displaying antigenic reactivity to anti-E-cadherin antibody are presumably on the surface and thus may be involved in cadherin-cadherin interaction. We have found three peptides from the EC-1 domain which are recognized by the anti-E-cadherin antibody. These peptides are in the two important regions of the EC-1 domain that was deduced from its secondary structure.

The chemistry associated with the process of N,O-acyl migration was explored in both cyclic and linear peptides under aqueous acid conditions. The importance of backbone cyclization and N-methylation of the peptide bond on the kinetics of N,O-acyl migration in a series of linear and cyclic peptides related in structure to cyclosporin A (CsA) were examined. The similarity in the chemical reactivity of the cyclic peptide [MeLeu (3-OH)]1-CsA and the corresponding linear peptide [Val-MeLeu (3-OH)-Abu], suggested that for this series, cyclization of the peptide backbone may not play an important role in controlling the kinetics of N,O-acyl migration. In contrast, the disparity in the chemical reactivity of tripeptides [Val-MeLeu (3-OH)-Abu] and [Val-Leu (3-OH)-Abu], indicated that N-methylation of amide bond significantly impacted the kinetics. Various hypothesis are proposed to account for this observation.

RGD peptides are known as important ligands for integrin receptors in the cell adhesion process. The selectivity of RGD peptides for a certain integrin receptor is partly dependent on the RGD conformation and the residues surrounding the RGD sequence. This paper investigates the effect of the addition of a phenylalanine residue on the RGD conformation in cyclo(1,6)Ac-Cys-Arg-Gly-Asp-Phe-Pen-NH2 (1) as compared to the previously studied cyclo(1,5)Ac-Pen-Arg-Gly-Asp-Cys-NH2 (2). The conformational study of peptide 1 was done in aqueous solution using nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulations. This work will increase the understanding of the flanking residue's effect in RGD peptides.

Cyclo(1,5)-Ac-Pen-Arg-Gly-Asp-Cys-NH2 (3) is a potent inhibitor of platelet aggregation. Nuclear magnetic resonance (NMR) and restrained molecular dynamics were used to study the conformations of 3. Elucidation of RGD conformations in 3 will increase the understanding of interaction between the RGD-sequence with GPIIb/IIIa.

Today, alloarthroplasty is one of the many standard therapeutical procedures in osteoarthrosis of the hip, or coxarthrosis. With this operation, many patients can be completely relieved from pain and regain their ability to walk to an excellent degree. However, long-term observations have shown that the stability of the prostheses does not always correlate with the life expectation of the operated patient. Dislocations and states of irritation, over and above infections, may necessitate repeat surgery. It must be borne in mind that such repeated operations are by no means certain to produce safe results. Hence, it is recommended to employ for the first implantation a prosthesis model which offers a better chance of interchangeability. This possibility is supplied by the double-cup prosthesis of the type described by Wagner and other authors. Certain limitations are imposed by the prosthetic form and by the surgical approach; these limitations should be taken into account when choosing the double-cup prosthesis.

The sequences of the homoeo domain containing the three alpha-helices were modeled based on secondary structure prediction, sequence homologies and coordinates of known helix-turn-helix motif containing DNA-binding proteins. The model reveals very similar three dimensional structure to repressors and suggest binding to DNA with its helix 3.