Kaitlyn Turo

Rudgers University

Drennan Laboratory
Mentor: Kaity Ryan

Summer 2007

The GTPase YjiA as a Homolog of Metal Ion Insertion Proteins

YjiA is suspected to bind metals as part of its role as a GTPase protein. Previous studies on homologous proteins, UreG and HypB, have described bindings, interactions, and insertions of Ni 2+ into target enzymes. Collaborators on YjiA have affirmed that YjiA binds both Ni 2+ and Zn 2+ . YjiA was successfully crystallized in 0.1 M HEPES pH 6.9 with 1.55 M Am 2 SO 4 , a condition unlike that previously published. Crystal morphology was optimized by the addition of 0.1 M Ca 2+. Crystals from this condition were soaked with GDP, GTP-g-S (a non-hydrolyzable GTP analog), Ni 2+ , and Zn 2+. Diffraction data were recently collected for each of these crystals. The native data set was solved to a resolution of 2.53 Å and appropriately matches the published structure. The data for the other four crystals are currently being analyzed to observe the success of the binding. Detection of a metal ion or GDP binding site may suggest a functional role for YjiA in Ni 2+ incorporation, similar to that of HypB or UreG.