Complementarity(redirected from complementarity-determining region (CDR))
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in molecular biology, the mutual correspondence that makes for the connection between complementary structures (macromoiecules, molecules, radicals) and is determined by the chemical properties of the structures.
According to J. Watson, complementarity is possible if the surfaces of the molecules have complementary structures, so that a protruding group or positive charge on one surface corresponds to a cavity or negative charge on the other; in other words, interacting molecules must fit one another like lock and key. The complementarity of chains of nucleic acids is based on the interaction of their nitrogenous bases. Thus, only when the arrangement is such that the adenine (A) in one chain is opposite the thymine (T) or uracyl (U) in the other and the guanine (G) in one is opposite the cytosine (C) in the other will there be hydrogen bonds between the bases of the chains. Complementarity seems to be the only and universal chemical mechanism for the storage and transmission of genetic information.
Another example of complementarity is the interaction of an enzyme with its corresponding substrate. In immunology, the word “complementarity” refers to the relationship between an antigen and its corresponding antibodies. The term “complementarity” is sometimes used in biological literature in a sense that is closely related to the concept of complementation.
REFERENCEWatson, J. Molekuliarnaia biologiia gena. Moscow, 1967. (Translated from English.)
V. N. SOIFER