STRUCTURAL COMPARISONS OF GLUTAMINE SYNTHETASE &CREATINE KINASE

University Of California San Francisco, San Francisco CA

Investigators

Linked publications & trials

Abstract

The study of structure-function relationships is extremely important to the understanding of proteins and protein engineering. We have set out to better understand structure function relationships through the structural comparisons of glutamine synthetase (GS) and creatine kinase (CK). The The Computer Graphics Laboratory resources are invaluable to this type of research. Using two new programs under development by the CGL (MinRMS and Chimera) and MidasPlus, we are able to generate an incredibly accurate multiple sequence files of GS and CK. These new tools enable us to look at the three dimensional alignments and sequence alignments simultaneously, thereby allowing us to fully visualize and compare catalytic residues and binding domains. GS and CK have no significant sequence similarity, yet they both have multimeric forms, similar tertiary structure, and catalyze similar reactions. GS catalyzes the reaction of glutamate and ammonia to form glutamine through a phosphorylated intermediate, while CK simply catalyzes the transfer of a phosphate group from ATP to creatine to yield phosphocreatine. The information we have gained from these resources indicates that a similar scaffold is used in both GS and CK. This scaffold also utilizes potentially homologous residues to bind ATP and assist in the transferance of the gamma phosphate. With this base of information we have an excellent model to continue our important study of structure-function relationships. Further studies of the multimer interfaces and substrate binding domains of these enzymes using CGL resources will continue to benefit this type of research throughout the year.