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Determination of protonation states of iminosugar-enzyme complexes using photoinduced electron transfer.

ABSTRACT: A series of N-alkylated analogues of 1-deoxynojirimycin containing a fluorescent 10-chloro-9-anthracene group in the N-alkyl substituent were prepared. The anthracene group acted as a reporting group for protonation at the nitrogen in the iminosugar because an unprotonated amine was found to quench fluorescence by photoinduced electron transfer. The new compounds were found to inhibit β-glucosidase from Phanerochaete chrysosporium and α-glucosidase from Aspergillus niger, with K_i values in the low micro- to nanomolar range. Fluorescence and inhibition versus pH studies of the β-glucosidase-iminosugar complexes revealed that the amino group in the inhibitor is unprotonated when bound, while one of the active site carboxylates is protonated.

SUBMITTER: Wang B

PROVIDER: S-EPMC5672842 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Determination of protonation states of iminosugar-enzyme complexes using photoinduced electron transfer.

Wang Bo B Olsen Jacob Ingemar JI Laursen Bo W BW Navarro Poulsen Jens Christian JC Bols Mikael M

Chemical science 20170914 11

A series of N-alkylated analogues of 1-deoxynojirimycin containing a fluorescent 10-chloro-9-anthracene group in the N-alkyl substituent were prepared. The anthracene group acted as a reporting group for protonation at the nitrogen in the iminosugar because an unprotonated amine was found to quench fluorescence by photoinduced electron transfer. The new compounds were found to inhibit β-glucosidase from Phanerochaete chrysosporium and α-glucosidase from Aspergillus niger< ...[more]

PMID: 29163889

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