Interrogating the Lactate Dehydrogenase Tetramerization Site Using (Stapled) Peptides

Lactate dehydrogenases
(LDHs) are tetrameric enzymes of major significance
in cancer metabolism as well as promising targets for cancer therapy.
However, their wide and polar catalytic sites make them a challenging
target for orthosteric inhibition. In this work, we conceived to target
LDH tetramerization sites with the ambition of disrupting their oligomeric
state. To do so, we designed a protein model of a dimeric LDH-H. We
exploited this model through WaterLOGSY nuclear magnetic resonance
and microscale thermophoresis for the identification and characterization
of a set of α-helical peptides and stapled derivatives that
specifically targeted the LDH tetramerization sites. This strategy
resulted in the design of a macrocyclic peptide that competes with
the LDH tetramerization domain, thus disrupting and destabilizing
LDH tetramers. These peptides and macrocycles, along with the dimeric
model of LDH-H, constitute promising pharmacological tools for the de novo design and identification of LDH tetramerization
disruptors. Overall, our study demonstrates that disrupting LDH oligomerization
state by targeting their tetramerization sites is achievable and paves
the way toward LDH inhibition through this novel molecular mechanism.