Structure-Guided Tuning of a Selectivity Switch towards Ribonucleosides in Trypanosoma brucei Purine Nucleoside 2'-Deoxyribosyltransferase.
Chembiochem
; 20(24): 2996-3000, 2019 12 13.
Article
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| MEDLINE
| ID: mdl-31264760
ABSTRACT
The use of nucleoside 2'-deoxyribosyltransferases (NDTs) as biocatalysts for the industrial synthesis of nucleoside analogues is often hindered by their strict preference for 2'-deoxyribonucleosides. It is shown herein that a highly versatile purine NDT from Trypanosoma brucei (TbPDT) can also accept ribonucleosides as substrates; this is most likely because of the distinct role played by Asn53 at a position that is usually occupied by Asp in other NDTs. Moreover, this unusual activity was improved about threefold by introducing a single amino acid replacement at position 5, following a structure-guided approach. Biophysical and biochemical characterization revealed that the TbPDTY5F variant is a homodimer that displays maximum activity at 50 °C and pHâ
6.5 and shows a remarkably high melting temperature of 69 °C. Substrate specificity studies demonstrate that 6-oxopurine ribonucleosides are the best donors (inosine>guanosineâ«adenosine), whereas no significant preferences exist between 6-aminopurines and 6-oxopurines as base acceptors. In contrast, no transferase activity could be detected on xanthine and 7-deazapurines. TbPDTY5F was successfully employed in the synthesis of a wide range of modified ribonucleosides containing different purine analogues.
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Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Pentosiltransferasa
/
Ribonucleósidos
/
Trypanosoma brucei brucei
Idioma:
En
Revista:
Chembiochem
Asunto de la revista:
BIOQUIMICA
Año:
2019
Tipo del documento:
Article
País de afiliación:
España