초록
<P><B>Highlights</B></P><P>► In the present work, we identified a <I>pduP</I>-encoded CoA-dependent propionaldehyde dehydrogenase of <I>Klebsiella pneumoniae</I>. ► Deletion of <I>pduP</I> abolished 3-HP synthesis in <I>K. pneumoniae</I>, especially at late stages of growth. ► Purified recombinant PduP showed broad enzymatic activity upon aliphatic aldehydes, including 3-hydroxypropionaldehyde. ► The present report is the first to confirm that the <I>pduP</I> gene is a member of the 3-HP biosynthesis pathway.</P> <P><B>Abstract</B></P><P>The <I>pduP</I> gene encodes a propionaldehyde dehydrogenase (PduP) was investigated for the role in 3-hydroxypropionic acid (3-HP) glycerol metabolism in <I>Klebsiella pneumoniae</I>. The enzyme assay showed that cell extracts from a <I>pduP</I> mutant strain lacked measurable dehydrogenase activity. Additionally, the mutant strain accumulated the cytotoxic intermediate metabolite 3-hydroxypropionaldehyde (3-HPA), causing both cell death and a lower final 3-HP titer. Ectopic expression of <I>pduP</I> restored normal cell growth to mutant. The enzymatic property of recombinant protein from <I>Escherichia coli</I> was examined, exhibiting a broad substrate specificity, being active on 3-HPA. The present work is thus the first to demonstrate the role of PduP in glycerol metabolism and biosynthesis of 3-HP.</P>