Inhibitory Peptides of the Sulfotransferase Domain of the Heparan Sulfate Enzyme, N-Deacetylase-N-sulfotransferase-1

Abstract

N-Deacetylase-N-sulfotransferase 1 (Ndst1) catalyzes theinitial modification of heparan sulfate and heparin duringtheir biosynthesis by removal of acetyl groups from subsets ofN-acetylglucosamine units and subsequent sulfation of theresulting free amino groups. In this study, we used a phage displaylibrary to select peptides that interact with Ndst1, withthe aim of finding inhibitors of the enzyme. The phage libraryconsisted of cyclic random 10-mer peptides expressed in thephage capsid protein pIII. Selection was based on the ability ofengineered phage to bind to recombinant murine Ndst1(mNdst1) and displacement with heparin. Peptides that wereenriched through multiple cycles of binding and disassociationdisplayed two specific sequences, CRGWRGEKIGNC andCNMQALSMPVTC. Both peptides inhibited mNdst1 activityin vitro, however, by distinct mechanisms. The peptide CRGWRGEKIGNCpresents a chemokine-like repeat motif (BXX,where B represents a basic amino acid and X is a nonchargedamino acid) and binds to heparan sulfate, thus blockingthe binding of substrate to the enzyme. The peptideNMQALSMPVT inhibits mNdst1 activity by direct interactionwith the enzyme near the active site. The discovery of inhibitorypeptides in this way suggests a method for developingpeptide inhibitors of heparan sulfate biosynthesis. (AU)