Coordinate-Dependent Drift-Diffusion Reveals the Kinetic Intermediate Traps of Top7-Based Proteins

J Phys Chem B. 2022 Dec 29;126(51):10854-10869. doi: 10.1021/acs.jpcb.2c07031. Epub 2022 Dec 15.

Abstract

The computer-designed Top7 served as a scaffold to produce immunoreactive proteins by grafting of the 2F5 HIV-1 antibody epitope (Top7-2F5) followed by biotinylation (Top7-2F5-biotin). The resulting nonimmunoglobulin affinity proteins were effective in inducing and detecting the HIV-1 antibody. However, the grafted Top7-2F5 design led to protein aggregation, as opposed to the soluble biotinylated Top7-2F5-biotin. The structure-based model predicted that the thermodynamic cooperativity of Top7 increases after grafting and biotin-labeling, reducing their intermediate state populations. In this work, the folding kinetic traps that might contribute to the aggregation propensity are investigated by the diffusion theory. Since the engineered proteins have similar sequence and structural homology, they served as protein models to study the kinetic intermediate traps that were uncovered by characterizing the position-dependent drift-velocity (v(Q)) and the diffusion (D(Q)) coefficients. These coordinate-dependent coefficients were taken into account to obtain the folding and transition path times over the free energy transition states containing the intermediate kinetic traps. This analysis may be useful to predict the aggregated kinetic traps of scaffold-epitope proteins that might compose novel diagnostic and therapeutic platforms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biotin* / metabolism
  • Epitopes
  • HIV Antibodies
  • HIV Envelope Protein gp41
  • Protein Folding*
  • Proteins / chemistry
  • Thermodynamics

Substances

  • Biotin
  • Proteins
  • Epitopes
  • HIV Envelope Protein gp41
  • HIV Antibodies