Thermochemistry of Binary and Ternary Protein Interactions Measured by Titration Calorimetry: Complex Formation of CD4, HIV gp120, and Anti-gp120

摘要: This chapter describes the use of solution biophysical technologies for quantitative analysis protein-protein interactions. Biophysical have potential revealing detailed, molecular information about binding mechanism protein interactions, such as stoichiometry, thermodynamics, coupled protonation events, and accurate determination affinity. However, interactions between proteins can be more complex than often assumed. An interpretation data in terms normally requires multiple methods to evaluate roles various processes that may oligomerization, folding, protonation, changes hydration. presents two applications. The first is binary interaction human receptor soluble CD4 immunodeficiency vius envelop gp 120. A strategy outlined characterizing evaluating commonly occuring side reactions conformational change. sCD4-gp 120 reaction has one largest enthalpy energies any interaction. origin this highly unusual feature assignes, after considering several possible origins, a large change within sCD4. second application builds on first, includes ternary formation sCD4, 120, anti-gp monoclonal antibody 48d. importance energetic constrainst set by thermodynamic cycle equilibrium described.