An ATP-dependent ligase with substrate flexibility involved in assembly of the peptidyl nucleoside antibiotic polyoxin.

An ATP-dependent ligase with substrate flexibility involved in assembly of the peptidyl nucleoside antibiotic polyoxin.
Appl Environ Microbiol. 2018 Apr 27;:
Authors: Gong R, Qi J, Wu P, Cai YS, Ma H, Liu Y, Duan H, Wang M, Deng Z, Price NPJ, Chen W
Abstract
Polyoxin (POL) is an unusual peptidyl nucleoside antibiotic, in which peptidyl moiety and nucleoside skeleton are linked by an amide bond. However, their biosynthesis remains poorly understood. Here, we report the deciphering of PolG as an ATP-dependent ligase responsible for the assembly of POL. A polG mutant is capable of accumulating multiple intermediates, including the peptidyl moiety (carbamoylpolyoxamic acid, CPOAA) and the nucleosides skeletons (POL-C and the previously overlooked thymine POL-C). We further demonstrated that PolG employs an ATP-dependent mechanism for amide bond formation, and that the generation of the hybrid nucleoside antibiotic, POL-N, is also governed by PolG. Finally, we determined that the deduced ATP-binding sites are functionally essential for PolG, and that they are highly conserved in a number of related ATP-dependent ligases. These insights have allowed us proposed a catalytic mechanism for the assembly of peptidyl nucleoside antibiotic via an acyl-phosphate intermediate, and have opened the way for the combinatorial biosynthesis/pathway engineering of this group of nucleoside antibiotics.Importance POL is well known for its remarkable antifun...

Source: Applied and Environmental Microbiology - April 27, 2018 Category: Microbiology Authors: Gong R, Qi J, Wu P, Cai YS, Ma H, Liu Y, Duan H, Wang M, Deng Z, Price NPJ, Chen W Tags: Appl Environ Microbiol Source Type: research