Tunicamycin inhibits GlcNAc-lipid formation in plants.

M.C Ericson,J.T Gafford,A.D Elbein

doi:10.1016/s0021-9258(17)40981-1

Abstract

Previous studies from this laboratory (Forsee, W. T., and Elbein, A. D. (1975) J. Biol. Chem. 250, 9283-9293; Forsee, W. T., Valkovich, G., and Elbein, A. D. (1976) Arch Biochem. Biophys. 174, 469-479) have shown that particulate extracts from cotton fibers and mung been seedlings catalyze the transfer of mannose from GDP-[14C]mannose and GlcNAc from UDP-[3H]GlcNAc into lipid-linked saccharides, Concentrations of tunicamycin of 5 microgram/ml or higher inhibit the incorporation of GlcNAc into GlcNAc-pyrophosphoryl-polyprenol but this antibiotic, even at 500 microgram/ml, had no effect on the synthesis of mannosyl-phosphoryldolichol. Tunicamycin also caused a slight inhibition in the incorporation of mannose into lipid-linked oligosaccharides. The concentration of tunicamycin necessary for inhibition was dependent on the amount of particulate enzyme in the incubations.

Highlights

We previously showed that particulate enzyme fractions from mung bean seedlings [10] and from cotton fibers [11]
We show that tunicamycin inhibits the formation of the GlcNAcpyrophosphoryl-polyprenol in mung beans and cotton, but has no effect on the formation of mannosyl-phosphoryl-polyprenol
This antibiotic markedly inhibited the incorporation of GlcNAc-pyrophosphoryl-dolichol and (GlcNAc) into lipid at concentrations as low as 5 @g/ml

Summary

Introduction

We show that tunicamycin inhibits the formation of the GlcNAcpyrophosphoryl-polyprenol in mung beans and cotton, but has no effect on the formation of mannosyl-phosphoryl-polyprenol. In all experiments involving tunicamycin, the enzyme was preincubated with antibiotic for 5 min at room temperature before adding other reaction components. The effect of tunicamycin concentration on the incorporation of mannose from GDP-[%]mannose into mannosyl-phosphoryl-polyprenol and of GlcNAc from UDP-[“H]GlcNAc into

Results

Conclusion