1. Characterization of the Highly Active Polyhydroxyalkanoate Synthase of Chromobacterium Sp. Strain Usm2
- Author
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Harvard University--MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology. Biomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology. Department of Biology, Massachusetts Institute of Technology. Engineering Systems Division, Sinskey, Anthony J., Brigham, Christopher J., Rha, ChoKyun, Bhubalan, Kesaven, Chuah, Jo-Ann, Shozui, Fumi, Taguchi, Seiichi, Sudesh, Kumar, Sinskey, Anthony J, Rha, Chokyun, Harvard University--MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology. Biomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology. Department of Biology, Massachusetts Institute of Technology. Engineering Systems Division, Sinskey, Anthony J., Brigham, Christopher J., Rha, ChoKyun, Bhubalan, Kesaven, Chuah, Jo-Ann, Shozui, Fumi, Taguchi, Seiichi, Sudesh, Kumar, Sinskey, Anthony J, and Rha, Chokyun
- Abstract
The synthesis of bacterial polyhydroxyalkanoates (PHA) is very much dependent on the expression and activity of a key enzyme, PHA synthase (PhaC). Many efforts are being pursued to enhance the activity and broaden the substrate specificity of PhaC. Here, we report the identification of a highly active wild-type PhaC belonging to the recently isolated Chromobacterium sp. USM2 (PhaC[subscript Cs]). PhaC[subscript Cs] showed the ability to utilize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) monomers in PHA biosynthesis. An in vitro assay of recombinant PhaC[subscript Cs] expressed in Escherichia coli showed that its polymerization of 3-hydroxybutyryl-coenzyme A activity was nearly 8-fold higher (2,462 ± 80 U/g) than that of the synthase from the model strain C. necator (307 ± 24 U/g). Specific activity using a Strep2-tagged, purified PhaC[subscript Cs] was 238 ± 98 U/mg, almost 5-fold higher than findings of previous studies using purified PhaC from C. necator. Efficient poly(3-hydroxybutyrate) [P(3HB)] accumulation in Escherichia coli expressing PhaC[subscript Cs] of up to 76 ± 2 weight percent was observed within 24 h of cultivation. To date, this is the highest activity reported for a purified PHA synthase. PhaC[subscript Cs] is a naturally occurring, highly active PHA synthase with superior polymerizing ability., Ministry of Science, Technology and Innovation, Malaysia
- Published
- 2011