Functional characterization of tlmH in Streptoalloteichus hindustanus E465-94 ATCC 31158 unveiling new insight into tallysomycin biosynthesis and affording a novel bleomycin analog.
Tallysomycins (TLMs) belong to the bleomycin (BLM) family of anticancer antibiotics and differ from the BLMs principally by the presence of a 4-amino-4,6-dideoxy-L-talose attached to C-41 of the TLM backbone as part of a glycosylcarbinolamide. To facilitate an understanding of the differences in anticancer activities observed between TLMs and BLMs, we thought to generate des-talose TLM analogs by engineering TLM biosynthesis in Streptoalloteichus hindustanus E465-94 ATCC 31158. Here we report (i) the engineering of the DeltatlmH mutant SB8005 strain that produces the two TLM analogs, TLM H-1 and TLM H-2, (ii) production, isolation, and structural elucidation of TLM H-1 and TLM H-2 by NMR and mass spectroscopic analyses as the desired des-talose TLM analogs, and (iii) comparison of the DNA cleavage activities of TLM H-1 with selected TLMs and BLMs. These findings support the previous functional assignment of tlmH to encode an alpha-ketoglutarate-dependent hydroxylase and unveil the TlmH-catalyzed hydroxylation at both C-41 and C-42 and the TlmK-catalyzed glycosylation of a labile carbinolamide intermediate as the final two steps for TLM biosynthesis. TlmH is apparently distinct from other enzymes known to catalyze carbinolamide formation. The availability of TLM H-1 now sets the stage to study the TlmH enzymology in vitro and to elucidate the exact contribution of the l-talose to the anticancer activities of TLMs in vivo.
Tao
Meifeng
M
Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA.
Wang
Liyan
L
Wendt-Pienkowski
Evelyn
E
Zhang
Ningning
N
Yang
Dong
D
Galm
Ute
U
Coughlin
Jane M
JM
Xu
Zhinan
Z
Shen
Ben
B
D000192:Actinomycetales / Q000235:genetics / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000737:chemistry; D001761:Bleomycin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D019906:Nuclear Magnetic Resonance, Biomolecular; D017384:Sequence Deletion
D000903:Antibiotics, Antineoplastic; D001761:Bleomycin; D004247:DNA; C016126:talisomycin