Molecular velcro

The crystal structure of the extracellular domain of P0 has also been determined [41]. The arrangement of molecules in the crystal indicates that P0 may exist on the membrane surface as a tetramer (Fig. 7-7) that can link to other tetramers from the opposing membrane to form an adhesive lattice, like a molecular Velcro . The structure also suggests that P0 mediates adhesion through the direct interaction of apically directed tryptophan side chains with the opposing membrane [42], in addition to homo-philic protein-protein interaction. 

Cloning would not be possible without restriction enzymes. DNA chains with a "sticky" end act like molecular "Velcro", thereby enabling two pieces of DNA with complementary nucleotide sequences to be joined together. The linking of the DNA strands is brought about by the enzyme DNAligase which permanently joins the assembled DNA sequences with covalent bonds, thereby producing a recombinant DNA molecule. 

Most applications of the biotin-avidin technology do not rely on the incorporation of the biotinylated probe within the protein environment provided by (strept) avidin. Typically, the introduction of a long spacer (at least five atoms) between the biotin anchor and the probe is recommended (Fig. 1). The biotin-avidin technology can thus be regarded as a molecular velcro that allows the bringing together of up to four biotinylated probes. 

Type III SAPs are known as molecular paint or molecular Velcro due to their ability to self-assemble onto surfaces, instead of self-assembling among themselves. This... 

McLendon, G. Control of Biological Electron Transport via Molecular Recognition and Binding The Velcro Model. Vol. 75, pp. 159-174. 

Molecular recognition and binding is the first step in protein electron-electron transfer. The foregoing data suggests that for the prototypical cyt c ccp system, this binding does not involve specific lock and key recognition, but rather involves complementary sticky patches of protein surfaces (rather like two pieces of velcro adhesive). 

Fig. 4 Deconstruction of crystalline Ru3(CO)i2 (a) a row of molecules constituting the crystal backbone is obtained by inserting one axial CO-ligand into a tetragonal cavity, formed by two axial and two radial COs on a next neighboring, equally oriented molecule (b) a molecular layer is obtained by placing other rows on both sides of the central one. uith the (CO)3 and (CO)4 units protruding from the surface affording a "Velcro"-type interaction for the incoming molecular layers. (From Ref. [17].)...

This keying idea has been applied to particles for example, Evans" stated, strength of (powder) compacts results mainly from the interlocking of irregularities on the particle surfaces. This concept is totally false. The same idea has also been applied to the binding of antigens to antibodies. It is a macroscopic idea which we have presumed is also true at the nanometer level. However, it is an idea which cannot be correct. There are no Velcro hooks and eyes at the molecular level. Newton knew this and dismissed the notion of hook d atoms. He found that the smoother he polished his glass marbles, the better they adhered. Atomically smooth surfaces stick best of aU. These conceptual problems have arisen because we assume that macroscopic behavior applies to molecules. Some critical observations show this to be a false premise. 

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