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An Enzyme Module System for the Synthesis of dTDP‐activated Deoxysugars from dTMP and Sucrose
Author(s) -
Elling Lothar,
Rupprath Carsten,
Günther Nicole,
Römer Ulrike,
Verseck Stefan,
Weingarten Petra,
Dräger Gerald,
Kirschning Andreas,
Piepersberg Wolfgang
Publication year - 2005
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200500037
Subject(s) - biochemistry , enzyme , sucrose synthase , biology , invertase
A flexible enzyme module system is presented that allows preparative access to important dTDP‐activated deoxyhexoses from dTMP and sucrose. The strategic combination of the recombinant enzymes dTMP‐kinase and sucrose synthase (SuSy), and the enzymes RmlB (4,6‐dehydratase), RmlC (3,5‐epimerase) and RmlD (4‐ketoreductase) from the biosynthetic pathway of dTDP‐β‐ L ‐rhamnose was optimized. The SuSy module (dTMP‐kinase, SuSy, ±RmlB) yielded the precursor dTDP‐α‐ D ‐glucose ( 2 ) or the biosynthetic intermediate dTDP‐6‐deoxy‐4‐keto‐α‐ D ‐glucose ( 3 ) on a 0.2–0.6 g scale with overall yields of 62 % and 72 %, respectively. A two‐step strategy in which the SuSy module was followed by the deoxysugar module (RmlC and RmlD) resulted in the synthesis of dTDP‐β‐ L ‐rhamnose ( 4 ; 24.1 μmol, overall yield: 35.9 %). Substitution of RmlC by DnmU from the dTDP‐β‐ L ‐daunosamine pathway of Streptomyces peucetius in this module demonstrated that DnmU acts in vitro as a 3,5‐epimerase with 3 as substrate to yield 4 (32.2 μmol, overall yield: 44.7 %). Chemical reduction of 3 with NaBH 4 gave a mixture of the C‐4 epimers dTDP‐α‐ D ‐quinovose ( 6 ) and dTDP‐α‐ D ‐fucose ( 7 ) in a ratio of 2:1. In summary, the modular character of the presented enzyme system provides valuable compounds for the biochemical characterization of deoxysugar pathways playing a major role in microbial producers of antibiotic and antitumour agents.