Specificity of chicken liver carbohydrate binding protein

Chicken hepatic lectin was isolated with affinity chromatography by using neoglycoproteins of bovine serum albumin (BSA) to which n moles of glycosides has been attached by amidination (Glycn-AI-BSA) [Lee, Y. C., Stowell, C. P., & Krantz, M. J. (1976) Biochemistry 15, 3956-3963] attached to Sepharose 4B. The same protein could be isolated from Man-, GlcNAc-, and Glc-AI-BSA-Sepharose columns and was identical with the protein previously reported [Kawasaki, T., & Ashwell, G. (1977) J. Biol. Chem. 252, 6536-6543]. The sugar specificity for binding to the isolated chicken hepatic lectin examined with Glycn-AI-BSA showed the order of potency for binding Glycn-AI-BSA to be D-GlcNAc greater than D-Glc, D-Man, L-Fuc greater than D-Gal, and the estimated Ki's for binding GlcNAc36-AI-BSA, Glc37-AI-BSA, Man33-AI-BSA, and L-Fuc28-AI-BSA were (6-20) X 10(-11), (2-3) X 10(-8), (3-9) X 10(-8), and 5 X 10(-8) M, respectively. The binding requirements of the binding protein were studied with a wide variety of Glycn-BSA's with different sugars and aglyconic linkages, as well as simple sugars and glycosides. It was concluded that (1) GlcNAc is the most potent sugar for binding, (2) the requirement for C-2 substituents is flexible, (3) an equatorial OH group at C-3 and C-4 must be present, (4) the 5-CH2OH group is not required for binding, (5) the lectin cannot accommodate a negative charge at C-6, and (6) D-Man and L-Fuc bind equally well.(ABSTRACT TRUNCATED AT 250 WORDS)