BioChem - DOS

Engineering an aldehyde dehydrogenase toward its substrates, 3-hydroxypropanal and NAD+, for enhancing the production of 3-hydroxypropionic acid

Scientific reports

Park, Ye Seop; Choi, Un Jong; Nam, Nguyen Hoai; Choi, Sang Jin; Nasir, Abdul; Lee, Sun-Gu; Kim, Kyung Jin; Jung, Gyoo Yeol; Choi, Sangdun; Shim, Jeung Yeop; Park, Sunghoon; Yoo, Tae Hyeon

<P>3-Hydroxypropionic acid (3-HP) can be produced via the biological route involving two enzymatic reactions: dehydration of glycerol to 3-hydroxypropanal (3-HPA) and then oxidation to 3-HP. However, commercial production of 3-HP using recombinant microorganisms has been hampered with several problems, some of which are associated with the toxicity of 3-HPA and the efficiency of NAD<SUP>+</SUP> regeneration. We engineered &alpha;-ketoglutaric semialdehyde dehydrogenase (KGSADH) from <I>Azospirillum brasilense</I> for the second reaction to address these issues. The residues in the binding sites for the substrates, 3-HPA and NAD<SUP>+</SUP>, were randomized, and the resulting libraries were screened for higher activity. Isolated KGSADH variants had significantly lower K<SUB>m</SUB> values for both the substrates. The enzymes also showed higher substrate specificities for aldehyde and NAD<SUP>+</SUP>, less inhibition by NADH, and greater resistance to inactivation by 3-HPA than the wild-type enzyme. A recombinant <I>Pseudomonas denitrificans</I> strain with one of the engineered KGSADH variants exhibited less accumulation of 3-HPA, decreased levels of inactivation of the enzymes, and higher cell growth than that with the wild-type KGSADH. The flask culture of the <I>P. denitrificans</I> strain with the mutant KGSADH resulted in about 40% increase of 3-HP titer (53 mM) compared with that using the wild-type enzyme (37 mM).</P>

2017

Nature Publishing Group UK

cc-by

2045-2322

7

pp.17155

10.1038/s41598-017-15400-x

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART79322622

https://www.nature.com/articles/s41598-017-15400-x.pdf