Recombination synapse

How are such intermediates formed from the parental duplexes and resolved to form products Many details for this process are now available, based largely on the results of studies of Cre recombinase from bacteriophage PI. This mechanism begins with the recombinase binding to the DNA substrates (Figure 27 39). Four molecules of the enzyme and their associated DNA molecules come together to form a. recombination synapse. The reaction begins with the... 

Figure 27.39. Recombination Mechanism. Recombination begins as two DNA molecules come together to form a recombination synapse. One strand from each duplex is cleaved by the recombinase enzyme the 3 end of each of the cleaved strands is linked to a tyrosine (Y) residue on the recombinase enzyme. New phosphodiester bonds are formed when a 5 end of the other cleaved strand in the complex attacks these tyrosine-DNA adducts. After isomerization, these steps are repeated to form the recombined products.

Cox B., Rosser M., Kozlowski M., Duwe K., Neve R., Neve K. Regulation and functional characterization of a rat recombinant dopamine D3 receptor. Synapse. 21 1, 1995. 

A transmitter substance is present in, and in many instances it is synthesized by, nerves it is released from the presynaptic terminals of the nerve fibres when they are stimulated. On release, it produces changes leading to the excitation or inhibition of neurones standing in synaptic relationship with those from which it has been liberated and after exerting its physiological action, it is inactivated by enzymatic destruction, by recombination into an inactive form in the presynaptic terminals or by diffusion from the region of the synapse. 

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