Molecular evolution of the lysine biosynthetic pathways

Area of Science:

• Biochemistry
• Molecular Biology
• Evolutionary Biology

Background:

• Lysine biosynthesis features two distinct anabolic pathways: diaminopimelic acid (DAP) and alpha-aminoadipic acid (AAA).
• A variant AAA pathway involving arginine and leucine biosynthesis enzymes has been identified in Thermus thermophilus.
• Understanding the evolutionary relationships between these pathways is crucial for comprehending metabolic diversity.

Purpose of the Study:

• To conduct a detailed genomic analysis of genes involved in both lysine anabolic routes (DAP and AAA).
• To investigate potential evolutionary relationships between the DAP and AAA pathways and related metabolic routes.
• To clarify the connections between lysine biosynthesis and arginine/leucine metabolism.

Main Methods:

• Genomic analysis of sequences for DAP and AAA pathway enzymes.
• Comparative analysis of genes involved in lysine, arginine, and leucine biosynthesis.
• Bioinformatic identification of evolutionary relationships between gene families.

Main Results:

• No evolutionary relationship was found between DAP and AAA pathway enzymes.
• The DAP pathway shows a clear relationship with arginine metabolism genes (lysC/argB, asd/argC, dapC/argD, dapE/argE, lysA/speAC).
• The AAA pathway is related to leucine biosynthesis and the tricarboxylic acid cycle, supporting previous findings.

Conclusions:

• The DAP and AAA lysine biosynthesis pathways are evolutionarily distinct.
• A strong link exists between the DAP pathway and arginine metabolism.
• The AAA pathway is connected to leucine biosynthesis, highlighting metabolic pathway interconnections.