A model for an antibody specific for the carcinoembryonic antigen (CEA) has been constructed using a method which combines the concept of canonical structures with conformational search. A conformational search technique is introduced which couples random generation of backbone loop conformations to a simulated annealing method for assigning side chain conformations. This technique was used both to verify conformations selected from the set of known canonical structures and to explore conformations available to the H3 loop in CEA ab initio. Canonical structures are not available for H3 due to its variability in length, sequence, and observed conformation in known antibody structures. Analysis of the results of conformational search resulted in three equally probable conformations for H3 loop in CEA. Force field energies, solvation free energies, exposure of charged residues and burial of hydrophobic residues, and packing of hydrophobic residues at the base of the loop were used as selection criteria. The existence of three equally plausible structures may reflect the high degree of flexibility expected for an exposed loop of this length. The nature of the combining site and features which could be important to interaction with antigen are discussed.
Modeling the anti-CEA antibody combining site by homology and conformational search.,Mas MT, Smith KC, Yarmush DL, Aisaka K, Fine RM Proteins. 1992 Dec;14(4):483-98. PMID:1438186[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Mas MT, Smith KC, Yarmush DL, Aisaka K, Fine RM. Modeling the anti-CEA antibody combining site by homology and conformational search. Proteins. 1992 Dec;14(4):483-98. PMID:1438186 doi:http://dx.doi.org/10.1002/prot.340140409
