Microheterogeneity among carbohydrate structures at the cell surface may be important in recognition phenomena.

Independently derived mutants of Chinese hamster ovary cells have been isolated and shown to exhibit a subtle glycosylation defect resulting in the premature termination of certain asparagine-linked carbohydrate moieties. This carbohydrate alteration is akin to the types of structural variation termed microheterogeneity and is thought not to affect the biological activities of glycoproteins that manifest the phenomenon. However, the carbohydrate change expressed by the mutants is stable and heritable, and 125I-lectin-binding studies suggest that it profoundly alters their surface recognition properties. The mutation appears to affect a specific subpopulation of galactose residues in asparagine-linked carbohydrate of the type found associated with the G glycoprotein of vesicular stomatitis virus. The mutant cells also exhibit morphological changes in substratum culture.