A quantitative model of thermal stabilization and destabilization of proteins by ligands.
Equilibrium binding ligands usually increase protein thermal stability by an amount proportional to the concentration and affinity of the ligand. High-throughput screening for the discovery of drug-like compounds uses an assay based on thermal stabilization. The mathematical description of this stabilization is well developed, and the method is widely applicable to the characterization of ligand-protein binding equilibrium. However, numerous cases have been experimentally observed where equilibrium binding ligands destabilize proteins, i.e., diminish protein melting temperature by an amount proportional to the concentration and affinity of the ligand. Here, we present a thermodynamic model that describes ligand binding to the native and unfolded (denatured) protein states explaining the combined stabilization and destabilization effects. The model also explains nonsaturation and saturation effects on the protein melting temperature when the ligand concentration significantly exceeds the protein concentration. Several examples of the applicability of the model are presented, including specific sulfonamide binding to recombinant hCAII, peptide and ANS binding to the Polo-box domain of Plk1, and zinc ion binding to the recombinant porcine growth hormone. The same ligands may stabilize and destabilize different proteins, and the same proteins may be stabilized and destabilized by different ligands.
Cimmperman
Piotras
P
Laboratory of Biothermodynamics and Drug Design, Institute of Biotechnology, LT-02241 Vilnius, Lithuania.
Baranauskiene
Lina
L
Jachimoviciūte
Simona
S
Jachno
Jelena
J
Torresan
Jolanta
J
Michailoviene
Vilma
V
Matuliene
Jurgita
J
Sereikaite
Jolanta
J
Bumelis
Vladas
V
Matulis
Daumantas
D
D000818:Animals; D002256:Carbonic Anhydrases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D011485:Protein Binding; D011489:Protein Denaturation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism; D011789:Quantum Theory; D013552:Swine / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics; D044366:Transition Temperature / Q000187:drug effects; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology; D000097869:Polo-Like Kinase 1
D002256:Carbonic Anhydrases; D018797:Cell Cycle Proteins; D013006:Growth Hormone; D008024:Ligands; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D015032:Zinc; D000097869:Polo-Like Kinase 1