Studies on the substrate specificity of a GDP-mannose pyrophosphorylase from Salmonella enterica

Lu Zou,Todd L Lowary,Ruixiang Blake Zheng

doi:10.3762/bjoc.8.136

Abstract

A series of methoxy and deoxy derivatives of mannopyranose-1-phosphate (Manp-1P) were chemically synthesized, and their ability to be converted into the corresponding guanosine diphosphate mannopyranose (GDP-Manp) analogues by a pyrophosphorylase (GDP-ManPP) from Salmonella enterica was studied. Evaluation of methoxy analogues demonstrated that GDP-ManPP is intolerant of bulky substituents at the C-2, C-3, and C-4 positions, in turn suggesting that these positions are buried inside the enzyme active site. Additionally, both the 6-methoxy and 6-deoxy Manp-1P derivatives are good or moderate substrates for GDP-ManPP, thus indicating that the C-6 hydroxy group of the Manp-1P substrate is not required for binding to the enzyme. When taken into consideration with other previously published work, it appears that this enzyme has potential utility for the chemoenzymatic synthesis of GDP-Manp analogues, which are useful probes for studying enzymes that employ this sugar nucleotide as a substrate.

Highlights

Modified sugar nucleotide analogues are valuable probes to study glycosyltransferases and other enzymes that use these activated glycosylating agents as substrates [1,2,3,4,5]
To further probe the potential of this enzyme for the chemoenzymatic synthesis of modified GDP-Manp derivatives, we describe here the preparation of all four singly methylated Manp-1P analogues 9–12, as well as the 6-deoxy-Manp-1P derivative 13, and an initial evaluation of their ability to serve as a substrate for S. enterica GDP-ManPP
9–13, in which one of the hydroxy groups was methylated or deoxygenated were generated by chemical synthesis, and the ability of these compounds to be converted to the corresponding GDP-Manp analogues by GDP-ManPP from S. enterica was evaluated

Summary

Introduction

Modified sugar nucleotide analogues are valuable probes to study glycosyltransferases and other enzymes that use these activated glycosylating agents as substrates [1,2,3,4,5]. To further probe the potential of this enzyme for the chemoenzymatic synthesis of modified GDP-Manp derivatives, we describe here the preparation of all four singly methylated Manp-1P analogues 9–12, as well as the 6-deoxy-Manp-1P derivative 13, and an initial evaluation of their ability to serve as a substrate for S. enterica GDP-ManPP.

Results

Conclusion