Xueyu Song of Iowa State University is supported by an award from the Theoretical and Computational Chemistry program to develop a realistic model of protein-protein interactions at the residue level. A key feature of the model is that it is parameterized using generic properties of twenty amino acids in nature and experimentally accessible properties of water and crystallization agents, and is therefore portable to all of the protein-protein interactions in aqueous solutions. A major effort in the research is the development of reliable methods to calculate the interactions which occur when the protein molecules are close together. In this situation, the molecular nature of the solution becomes important. Song and his group are studying the crystallization of lysozyme, which is well characterized experimentally. In these studies they are striving to understand the reasons lysozyme crystallization occurs under certain conditions in a lysozyme-ammonium-sulfate-water system. Studies on the crystallization of crystallins and their various mutants are also being performed.
From these studies new insights into the mechanism of protein crystallization, will be gained. It may also be possible to more fully understand the formation of cataracts which involves a protein crystallization process. The work is, thus, having a broad impact on the field of biology but is also having a broad impact through the training of students in an interdisciplinary area of study. Song is also including undergraduate students from the REU center he directs in his research, further broadening its impact.
