ANALOGOUS SALICYLIC ACID AFFINITY REGIONS IN SERUM ALBUMIN AND SOYBEAN BETA-CONGLYCININ

摘要

The known structures of human serum albumin and its binding sites for salicylic acid (SA) were used as a model for examining the amino acid sequence of soybean beta-conglycinin to determine whether a plant protein might share structural similarities with albumin relative to the binding of SA. Molecular mechanics energy calculations for computed nonionized and ionized interactions in vacuo identified the two major SA affinity regions in human serum albumin and a single analogous region in the alpha-subunit of soybean beta-conglycinin. SA interactions with 21-residue segments from both proteins suggest redundant binding sites with multiple degrees of affinity. High-affinity segments incorporate hydrophobic amino acids with combinations or multiple residues of histidine, tryptophan, lysine, or arginine in keeping with a preference of SA for homopolymers of these acids over other homopolypeptides. Residue spacing also seems important. High affinity is associated with but not imparted by genetic similarity. Profiles from beta-sheet conformations simplify identification of analogous segments. [References: 14]