 selma ( selection 
 with modified aptamers ) is a directed evolution 
 method which can be used to develop dna - supported clusters of carbohydrates 
 in which the geometry of clustering is optimized for strong recognition 
 by a lectin of interest . 
 herein , we report a modification of selma 
 which results in glycoclusters which achieve dramatically stronger 
 target recognition ( 100-fold ) with dramatically fewer glycans ( 23-fold ) . 
 our first applications of selma yielded clusters of 510 oligomannose 
 glycans which were recognized by broadly neutralizing hiv antibody 
 2g12 with moderate affinities ( 150500 nm kd s ) . 
 in the present manuscript , we report glycoclusters 
 containing just 34 glycans , which are recognized by 2g12 with kd s as low as 1.7 nm . these glycoclusters 
 are recognized by 2g12 as tightly as is the hiv envelope protein gp120 , 
 and they are the first constructs to achieve this tight recognition 
 with the minimal number of man9units ( 34 ) necessary to occupy the binding sites 
 on 2g12 . 
 they are thus of great interest as immunogens which 
 might elicit broadly neutralizing antibodies against hiv . 
Supplementary Material