Katie Mitchell-KochKatie Mitchell-Koch
Assistant Professor, Chemistry
Wichita State University

Structure-dynamics of cofactor binding in human aldose reductases (2017-18)

The human aldose reductase enzymes are involved in processes that give rise to diabetic complications and resistance to chemotherapy treatments in cancer patients. This work provides atomic-level details of the protein structures, which will provide valuable information as drugs are being developed to target these enzymes.

This project investigates fundamental structure-dynamics-function relationships in the human aldose reductase enzymes, which are drug targets for treatment of diabetes and several types of cancer. Although there is spectroscopic evidence suggesting that protein conformational changes accompany cofactor binding and release, which is rate-contributing, no atomic-level detail of these conformations is currently available. Furthermore, a crystal structure of AKR1B15 is not available presently, although a homology model has been proposed.

Aim #1 will characterize cofactor binding in AKR1B10 and AKR1B15 through crystallographic studies. The human aldose reductase enzymes AKR1B10 and AKR1B15 will be expressed ad purified by the PSFCOBRE Protein Production Lab for the purpose of structural studies. Crystallization of the protein will be carried out at the PSF-COBRE Protein Structure Lab, with the goal to obtain structures for AKR1B10 complexed with NADPH cofactor; AKR1B15 apo-protein (without cofactor), and AKR1B15 complexed with both NADP+ and NADPH cofactors.

In Aim #2, molecular dynamics simulations of holo and apo enzymes of AKR1B10 and AKR1B15 will be conducted and analyzed, comparing conformational dynamics in NADP+ vs. NADPH-bound enzymes. Analysis will focus on structural characteristics of cofactor binding (close contacts, hydrogen bonds), enzyme conformational changes associated with binding, and comparison of enzyme conformational dynamics with and without cofactors.