Proteins that mimic

Complement Some microorganisms produce proteins that bind to and inactivate components of the complement system and hence decrease activation of the cascade, e.g. the vaccinia virus secretes a protein that inhibits activation of both the classical and alternative pathways. Some bacteria produce a protein that mimics the action of an acceleration factor, which increases the rate of destruction of the active convertase this factor is normally produced by the host when the complement response is no longer required. 

Cytokines Some microorganisms produce proteins that mimic receptors for the cytokines these sequester the cytokines and prevent them from reaching their normal targets. 

Natural products from the Euphorbiaccae family of plants that mimic the effects of diacylglycerol by binding the Cl domain of proteins such as PKC. 

The first elastomeric protein is elastin, this structural protein is one of the main components of the extracellular matrix, which provides stmctural integrity to the tissues and organs of the body. This highly crosslinked and therefore insoluble protein is the essential element of elastic fibers, which induce elasticity to tissue of lung, skin, and arteries. In these fibers, elastin forms the internal core, which is interspersed with microfibrils [1,2]. Not only this biopolymer but also its precursor material, tropoelastin, have inspired materials scientists for many years. The most interesting characteristic of the precursor is its ability to self-assemble under physiological conditions, thereby demonstrating a lower critical solution temperature (LCST) behavior. This specific property has led to the development of a new class of synthetic polypeptides that mimic elastin in its composition and are therefore also known as elastin-like polypeptides (ELPs). 

Both influx and efflux transporters are located in intestinal epithelial cells and can either increase or decrease oral absorption. Influx transporters such as human peptide transporter 1 (hPEPTl), apical sodium bile acid transporter (ASBT), and nucleoside transporters actively transport drugs that mimic their native substrates across the epithelial cell, whereas efflux transporters such as P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and breast cancer resistance protein (BCRP) actively pump absorbed drugs back into the intestinal lumen. 

Another direction in liquid crystal research is the fabrication of new molecules that mimic natural materials. The molecule shown here forms two different liquid crystals because of the cylindrical properties of the color-shaded portions of the molecule. These two trios are tethered together by long hydrocarbon chains. In addition to forming liquid crystals, this molecule self-assembles into organized larger units, as do proteins and DNA. The techniques used to synthesize this particular molecule can be adapted to incorporate... 

Gaertner, H.F., Offord, R.E., Cotton, R., Timms, D., Camble, R., and Rose, K. (1994) Chemo-enzymic backbone engineering of proteins. Site-specific incorporation of synthetic peptides that mimic the 64-74 disulfide loop of granulocyte colony-stimulating factor. J. Biol. Chem. 269, 7224-7230. 

Synthetic models of myoglobin and hemoglobin are complex molecules that mimic the stereochemical properties of the protein active center [24] and have oxygen affinities similar to those measured for the protein [25-27]. The first heme model that reversibly binds oxygen (i.e. the picket-fence-oxygen complex Fe(TpivPP)(l,2-Melm)(02), shown in Fig. 3.3) was obtained in the early nine-teen-seventies by Collman and coworkers (TpivPP = tetrapivalami-nophenyl porphyrin 2-meIm = 2-methylimidazole) [18]. Research on synthetic models of the protein has led to a deeper understand-... 

---