Acid phosphatase/phosphotransferases from enteric bacteria

Area of Science:

• Enzymology
• Microbial biochemistry
• Molecular biology

Background:

• Morganella morganii phoC acid phosphatase displays pyrophosphate (PP(i))-nucleoside phosphotransferase activity.
• Acid phosphatases are crucial enzymes in various biological processes.

Purpose of the Study:

• To isolate and characterize acid phosphatases with regioselective phosphotransferase activity (AP/PTase) from bacterial species.
• To compare the enzymatic characteristics and primary structures of these enzymes with M. morganii AP/PTase.
• To investigate the synthesis of inosine-5 '-monophosphate (5 '-IMP) using these enzymes.

Main Methods:

• Gene isolation of AP/PTase from Providencia stuartii, Enterobacter aerogenes, Escherichia blattae, and Klebsiella planticola.
• Comparative analysis of primary structures and enzymatic properties.
• Assessment of 5 '-IMP production in E. coli overexpressing the isolated acid phosphatases.

Main Results:

• Isolated AP/PTases showed high homology with M. morganii AP/PTase and belong to class A1 acid phosphatases.
• The P. stuartii enzyme demonstrated high 5 '-IMP productivity, comparable to the M. morganii enzyme.
• Enzymes from E. aerogenes, E. blattae, and K. planticola exhibited lower 5 '-IMP productivity, suggesting K(m) values influence efficiency.

Conclusions:

• Bacterial AP/PTases share significant structural homology but exhibit varying efficiencies in nucleotide synthesis.
• Differences in nucleotide production efficiency are likely due to local sequence variations within the enzyme's binding pocket.
• Optimizing K(m) values is critical for enhancing nucleotide production using these phosphotransferase enzymes.