Some useful ideas for multistate protein design: Effect of amino acid substitutions on the multistate proteins stability and the rate of protein structure formation.

The design of new protein variants is usually confined to slightly "fixing" an already existing protein, adapting it to certain conditions or to a new substrate. This is relatively easy to do if the fragment of the protein to be affected, such as the active site of the protein, is known. But what if you need to "fix" the stability of a protein or the rate of its native or intermediate state formation? Having studied a large number of protein mutant forms, we have established the effect of various amino acid substitutions on the energy landscape of the protein. As a result, we have revealed a number of patterns to help researchers identify amino acid residues that determine the folding rate and the stability of globular proteins states and design a mutant form of a protein with desired properties.

[Effect of Substitutions in Surface Amino Acid on Energy Profile of Apomyoglobin].

Studies on the process of spontaneous protein folding into a unique native state are an important issue of molecular biology. Apomyoglobin from the sperm whale is a convenient model for these studies in vitro. Here, we present the results of equilibrium and kinetic experiments carried out in a study on the folding and unfolding of eight mutant apomyoglobin forms of with hydrophobic amino acid substitutions on the protein surface. Calculated values of apparent constants of folding/unfolding rates, as well as the data on equilibrium conformational transitions in the urea concentration range of 0-6 М at 11°C are given. Based on the obtained information on the kinetic properties of the studied proteins, a Φ-value analysis of the transition state has been performed and values of urea concentrations corresponding to the midpoint of the transition from the native to intermediate state have been determined for the given forms of mutant apomyoglobin. It has been found that a significant increase in the stability of the native state can be achieved by a small number of amino acid substitutions on the protein surface. It has been shown that the substitution of only one amino acid residue exclusively affects the height of the energy barrier that separates different states of apomyoglobin.