A chaperone-like function of intramolecular high-mannose chains in the oxidative refolding of bovine pancreatic RNase B.

This paper describes a chaperone-like function of the intramolecular N-glycans of bovine pancreatic RNase B. We studied air-oxidative regeneration from reductively denatured species of RNase B and its nonglycosylated form, RNase A. RNase B was reactivated much faster than RNase A, while RNase A was liable to aggregate during the regeneration. An Asn-linked oligosaccharide, Man5GlcNA2Asn, which corresponds to the most predominant sugar chain (ca. 60%) of RNase B, enhanced the reactivation of the denatured RNases A and B. The stimulatory effect of this Asn-oligosaccharide revealed that the N-glycans of RNase B facilitate the transformation of bulky intermediates into folded, compact species.