A ¹H NMR study of the specificity of α-l-arabinofuranosidases on natural and unnatural substrates.
Biochim Biophys Acta
; 1840(10): 3106-14, 2014 Oct.
Article
em En
| MEDLINE
| ID: mdl-25016078
ABSTRACT
BACKGROUND:
The detailed characterization of arabinoxylan-active enzymes, such as double-substituted xylan arabinofuranosidase activity, is still a challenging topic. Ad hoc chromogenic substrates are useful tools and can reveal subtle differences in enzymatic behavior. In this study, enzyme selectivity on natural substrates has been compared with enzyme selectivity towards aryl-glycosides. This has proven to be a suitable approach to understand how artificial substrates can be used to characterize arabinoxylan-active α-l-arabinofuranosidases (Abfs).METHODS:
Real-time NMR using a range of artificial chromogenic, synthetic pseudo-natural and natural substrates was employed to determine the hydrolytic abilities and specificity of different Abfs.RESULTS:
The way in which synthetic di-arabinofuranosylated substrates are hydrolyzed by Abfs mirrors the behavior of enzymes on natural arabinoxylo-oligosaccharide (AXOS). Family GH43 Abfs that are strictly specific for mono-substituted d-xylosyl moieties (AXH-m) do not hydrolyze synthetic di-arabinofuranosylated substrates, while those specific for di-substituted moieties (AXH-d) remove a single l-arabinofuranosyl (l-Araf) group. GH51 Abfs, which are supposedly AXH-m enzymes, can release l-Araf from disubstituted d-xylosyl moieties, when these are non-reducing terminal groups. CONCLUSIONS AND GENERALSIGNIFICANCE:
The present study reveals that although the activity of Abfs on artificial substrates can be quite different from that displayed on natural substrates, enzyme specificity is well conserved. This implies that carefully chosen artificial substrates bearing di-arabinofuranosyl d-xylosyl moieties are convenient tools to probe selectivity in new Abfs. Moreover, this study has further clarified the relative promiscuity of GH51 Abfs, which can apparently hydrolyze terminal disubstitutions in AXOS, albeit less efficiently than mono-substituted motifs.Palavras-chave
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Bases de dados:
MEDLINE
Assunto principal:
Oligossacarídeos
/
Bacillus
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Proteínas de Bactérias
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Glicosídeo Hidrolases
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
França