Unusual distributions of amino acids in complementarity-determining (hypervariable) segments of heavy and light chains of immunoglobulins and their possible roles in specificity of antibody-combining sites.

From the $National CancerInstitute, National Institutes ofHealth, Bethesda, Maryland 20014, and the Departments of Microbiology, Human Genetics and Development and Neurology, Columbia University, and the Neurological Institute, Presbyterian Hospital, New York, New York 10032;s the Departments of Engineering Sciences and Biochemistry and Molecular Biology, Northwestern University, Evanston, Illinois 60201; and j(Bolt Beranek and Newman Inc., Cambridge, Massachusetts 02138