Fluorous-assisted synthesis of (E)-5-[3-Aminoallyl]-uridine-5′-triphosphate

A cocktail of protein engineering strategies: breaking the enzyme bottleneck one by one for high UTP production in vitro

The pyrimidine metabolic pathway is tightly regulated in microorganisms, allowing limited success in metabolic engineering for the production of pathway-related substances. Here, we constructed a four-enzyme coupled system for the in vitro production of uridine triphosphate (UTP). The enzymes used include nucleoside kinase, uridylate kinase, nucleoside diphosphate kinase, and polyphosphate kinase for energy regeneration. All these enzymes are derived from extremophiles. To increase the total and unit time yield of the product, three enzymes other than polyphosphate kinase were modified separately by multiple protein engineering strategies. A nucleoside kinase variant with increased specific activity from 2.7 U/mg to 36.5 U/mg, a uridylate kinase variant (specific activity of 37.1 U/mg) with a 5.2-fold increase in thermostability, and a nucleoside diphosphate kinase variant with a 2-fold increase in specific activity to over 900 U/mg were obtained, respectively. The reaction conditions of the coupled system were further optimized, and a two-stage method was taken to avoid the problem of enzymatic pH adaptation mismatch. Under optimal conditions, this system can produce more than 65 mM UTP (31.5 g/L) in 3.0 h. The substrate conversion rate exceeded 98% and the maximum UTP productivity reached 40 mM/h. This article is protected by copyright. All rights reserved.

Concise and efficient synthesis of 3'-O-tetraphosphates of 2'-deoxyadenosine and 2'-deoxycytidine

We describe concise and efficient synthesis of biologically very important 3'-O-tetraphosphates namely 2'-deoxyadenosine-3'-O-tetraphosphate (2'-d-3'-A4P) and 2'-deoxycytidine-3'-O-tetra-phosphate (2'-d-3'-C4P). N(6)-benzoyl-5'-O-levulinoyl-2'-deoxyadenosine was converted into N(6)-benzoyl-5'-O-levulinoyl-2'-deoxyadenosine-3'-O-tetraphosphate in 87% yield using a one-pot synthetic methodology. One-step concurrent deprotection of N(6)-benzoyl and 5'-O-levulinoyl groups using concentrated aqueous ammonia resulted 2'-d-3'-A4P in 74% yield. The same synthetic strategy was successfully employed to convert N(4)-benzoyl-5'-O-levulinoyl-2'-deoxycytidine into 2'-d-3'-C4P in 68% yield.

Short and straightforward synthesis of triphosphates of artificial nucleobase pairs displaying unconventional pairing scheme

Concise, facile and efficient synthesis of 5'-O-triphosphates of 6-amino-5-nitro-3-(1'-β-D-2'-deoxyribofuranosyl)-2(1H)-pyridone (dZ) and its Watson-Crick complement 2-amino-8-(1'-β-D-2'-deoxyribofuranosyl)-imidazo[1,2a]-1,3,5-triazin-4(8H)-one (dP) is reported using a one-pot synthetic procedure.

Fluorous-assisted synthesis of (E)-5-[3-aminoallyl]-uridine-5'-O-triphosphate

An efficient, reliable method for the chemical synthesis of (E)-5-[3-aminoallyl]-uridine-5'-O-triphosphate (AA-UTP), starting from 5-iodouridine, is described. This new strategy features the involvement of one-pot triphosphate formation and fluorous solid-phase extraction (F-SPE). The one-pot synthesis involves the mono phosphorylation of fluorous-tagged uridine, followed by the reaction with pyrophosphate to afford the fluorous-tagged AA-UTP. The F-SPE is achieved by installing a fluorous-tag onto the uridine prior to triphosphate formation, purification via F-SPE, and cleavage of the fluorous-tag. It is worth mentioning that this protocol produces AA-UTP in high yield and purity using one simple F-SPE; no conventional column chromatography is involved.