Difference between revisions of "Part:BBa K2739008"

Revision as of 21:58, 10 October 2018

Bktb

BtkB is paralogous to the phaA protein, which is involved in the bioplastic Polyhydroxyalkanoate (PHA) synthetic pathway. The PHA pathway is usually conducted through the PHA operon, which involve 3 enzymatic reactions. PhaA catalyses the first step of the pathway and allow the formation of acetoacetyl-CoA through condensation of two molecules of acetyl-CoA. The bktB was isolated from R. eutropha H16, and instead of forming acetoacetyl-CoA, it allows the formation of 3-ketovaleryl-CoA and contribute to the formation of PHBV end product.

Usage and Biology

BktB's main function is to form the 3-ketovaleryl-CoA through condensation of two moleculesof acetyl-CoA. BktB was isolatedfrom R. eutrophaH16 as the most importantparalogous genefor PHBV production since itshowed higher substrate specificity to the C5 monomer and used 3-ketovaleryl-CoA more efficiently (Mifune et al 2010). The kinetic properties analysis of phaA and BktB revealed that the specific activity of PhaA is 150 fold lowerthan BktBif 3-ketovaleryl-CoA was used as substrates, and the abilityof PhaA and BktB to incorporate 3HV fraction in produced PHBV differed when growing in M9 minimal medium with 1% glucose and different amount propionate(Slater et al., 1998).This result was further supported by themselves analysing and comparing bktBmutant strainwith wild type R. eutropha, which indicated BktB was responsible for generating 3HV in PHBV(ibid).

Sequence and Features