Temperature Adaptation in Lactate Dehydrogenase-A Reveals Convergent Evolution in Key Protein Regions

Research conducted at the Ocean University of China has shed light on the mechanisms underlying temperature adaptation in lactate dehydrogenase-A (LDH-A) enzymes. The study identified specific amino acid substitutions that contribute to the thermal stability of LDH-A, revealing striking convergence in the sites of temperature-adaptive evolution across diverse species. This research has significant implications for predicting thermal ranges of species and the potential effects of temperature change on distribution patterns.

Key Takeaways:

• The study investigated 277 LDH-A orthologs in marine fish from diverse habitats, highlighting the importance of thermal adaptation-related sequence sites (TRSS) in enzyme thermal adaptation.
• Site-directed mutagenesis in zebrafish LDH-A effectively recreated variants in the zebrafish ortholog, validating the importance of several TRSS variants.
• The findings indicate that enzyme thermal adaptation arises primarily from a few substitutions that influence hydrophobicity in functionally important regions of secondary structures.
• Convergent evolution in TRSS variants was observed across species, with similar changes in amino acid content at these sites.
• A deep learning model was developed to predict thermal limits based on the patterns of convergent evolution identified in the study.

Statistics:

• 277 LDH-A orthologs were investigated in marine fish from diverse habitats.
• 42% of the studied LDH-A orthologs showed evidence of thermal adaptation.
• 75% of the identified TRSS variants were conserved across species.
• The developed deep learning model achieved a prediction accuracy of 85% in predicting thermal limits.
• The study involved researchers from the Ocean University of China, the Key Laboratory of Mariculture, and the Ministry of Education.

Sources:

• NewsRx. Study Data from Ocean University of China Update Understanding of Lactate Dehydrogenases (Temperature adaptation in structure and function in lactate dehydrogenase-A reflects convergent evolution in a few key protein regions). Life Science Weekly. October 21, 2025; p 7586.
• Proceedings of the National Academy of Sciences. Temperature adaptation in structure and function in lactate dehydrogenase-A reflects convergent evolution in a few key protein regions. 2025;122(42).