Faculty Advisor

Grinstead, Jeff

Area of Study

Science and Mathematics

Publication Date

Summer 2011


AppA is a protein in Rhodobacter sphaeroides that has been the topic of debate among scientists for the past several years with regards to the structure of the protein. It has been known that AppA has an effect on the activity of PpsR, which controls the gene expression of photosystems. There are two conflicting experimental structures (2IYG and 1YRX) of the protein, both of which claim to be taken in the dark phase (meaning when there is no light shining on the protein). The debate is about whether some slight differences in the structures represent the shift from the dark state to the light-induced state. It is known that in the light state, AppA releases PpsR and undergoes a dimerization event with itself. We observed the interactions within an experimental structure of the AppA dimer and compared them to the 2IYG and 1YRX structures. Most scientists have focused on the positioning of Trp104 to explain the functional changes of AppA upon light excitation, but our analysis of experimental structures suggests that the dimerization could play a larger role in the functional mechanism of AppA.


University of Puget Sound

Summer Research Symposium response.docx (14 kB)
Tieu_summer_2011_poster.ppt (1720 kB)
Poster in MS Powerpoint format

Included in

Biochemistry Commons