Technical Staff Member (Scientist 3)

Expertise: (i) Structural and functional analysis of proteins, (ii) X-ray crystallography. (iii) molecular biology and genetic engineering, (iv) Large scale cloning and protein/antibody purification, (v) High throughput proteins' ligand analysis, (vi) Structure-based drug development for Mtb & Influenza virus targets, (vii) High throughput drug target analysis, (viii) Identification and optimization of drug leads, (ix)Academic training; research advising for undergraduate and graduate student. (Personal Statement) I have a broad background in the field of biochemistry and biophysics with specific training of ligand-related structure-function analysis of wide range of proteins. Through Ph. D. and the 1st Post-Doc period, I was involved in nucleic acid ligands-eukaryotic initiation factor (eIFiso-4F) interaction analysis project, which was investigated by protein chemistry approach. During the 2nd Post-Doc period, my research focused on the interaction of DNA and metal ligands with human DNA repair proteins, flap endonuclease-1(FEN-1) and XPG using Fourier transform infrared (FT-IR) and small angle X-ray scattering (SAXS) techniques. For the first 15 years in my career at Los Alamos National Laboratory (LANL), I have led the high throughput cloning and protein production facility with annual ~$1 million support from the NIH through five large-scale structural genomics projects. In these projects, my lab contributed to over 50 structures in the Protein Data Bank. Particularly, we initiated the project to develop dye-ligand affinity chromatography (DLAC) technique. The Cibacron Blue dye has an unusual character to bind nucleot(s)ide interacting enzymes with its unique feature of structural similarity to common nucleot(s)ides. Using this dye-resin's capability to interact with this large group of important enzymes, after confirmation of binding ~ 50% of Mycobacterium tuberculosis (Mtb) cell extract proteins onto the dye-resin, we showed the selective elution of proteins by nucleot(s)ide ligands from this resin as a high throughput assay for protein-ligand interactions, and reported the dramatic enhancement of protein crystallization with aid of ligands identified by this DLAC approach. By application of ligand data obtained from DLAC approach to structural analysis of Mtb proteins, we could raise success rate of protein crystallization from 20-30 % up to 50 %. Implementing this DLAC for drug target analysis by using drugs as eluting ligands, we have pursued to identify targets of anti-tb drugs from Mtb cell extract. Based on the Mtb drug target information, we have developed a new program on drug discovery for tuberculosis. Lately, we also have discovered the conditions that can overcome the encapsulation of nonionic detergent micelles on anionic dye. Under these conditions, our DLAC approach can be used to identify the interacting membrane proteins of the applied ligands. Based on this result, we are developing the research programs to identify Mtb membrane protein targets of the reported anti-Mtb drugs (the inhibitory drugs for Mtb growth) using our DLAC technique. The data for Mtb membrane drug target proteins, which have never been explored, will give crucial information for the discovery of unique anti-tb drugs. In our current projects, we are developing drugs against Mtb persistent target, L-alanine dehydrogenase (L-alaDH) and a novel and essential drug target, 6-phosphogluconate dehydrogenase (6-PGDH), human orthologous cancer target, 6-PGDH, Burkholderia pseudomallei efflux pump membrane proteins, and the complexes of human and virus proteins (p85β, CrkL + NS1) by lead identification, co-crystallization of target and lead(s), optimization of identified leads and efficacy test of optimized compounds. Through these projects, we have established the drug discovery pipeline facilities for early drug development processes; (1) lead generation by the DLAC, (2) target activity inhibition assay and enzyme kinetics analysis, (3) co-crystal structure analysis with target and leads, (4) modeling by docking with simulation programs, (5) optimization of leads by drug design and synthesis based on the models of target protein and leads, (6) cytotoxicity test, and (7) minimum inhibition concentration test to make the optimized compounds against targets to move forward for the next steps of drug development process, pharmacokinetics, ADME, pharmacodynamics, animal and preclinical tests.