Heungbok Kim

Microsphere-based protease assays and screening application for lethal factor and factor Xa.

Proteases regulate many biological pathways in humans and are components of several bacterial toxins. Protease studies and development of protease inhibitors do not follow a single established methodology and are mostly protease specific.

Direct fluorescent staining and analysis of proteins on microspheres using CBQCA.

General methods for accurate determination of microsphere surface protein loading are needed for applications from protein arrays to molecular assembly studies. Current methods include bulk absorption measurements of stained microspheres or use of known fluorescently tagged binding partners, which limit sensitivity and general applicability, respectively.

Enhancement of crystallization with nucleotide ligands identified by dye-ligand affinity chromatography

Ligands interacting with Mycobacterium tuberculosis recombinant proteins were identified through use of the ability of Cibacron Blue F3GA dye to interact with nucleoside/nucleotide binding proteins, and the effects of these ligands on crystallization were examined. Co-crystallization with ligands enhanced crystallization and enabled X-ray diffraction data to be collected to a resolution of at least 2.7 Å for 5 of 10 proteins tested. Additionally, clues about individual proteins’ functions were obtained from their interactions with each of a panel of ligands.

Chemical shift assignments for Rv0577, a putative glyoxylase associated with virulence from Mycobacterium tuberculosis.

Approximately one-third of mankind has been exposed to Mycobacterium tuberculosis, the etiological agent responsible for tuberculosis (TB). As part of an effort to develop a new generation of anti-TB agents, the chemical shifts for the 261-residue, virulence-associated protein Rv0577 from M. tuberculosis has been extensively assigned.

1.55 Å resolution X-ray crystal structure of Rv3902c from Mycobacterium tuberculosis.

The 1.55 Å resolution X-ray crystal structure of Rv3902c from M. tuberculosis reveals a novel fold.

Expression, purification and preliminary crystallographic analysis of O-acetylhomoserine sulfhydrylase from Mycobacterium tuberculosis.

The gene product of the open reading frame Rv3340 from Mycobacterium tuberculosis is annotated as encoding a probable O-acetylhomoserine (OAH) sulfhydrylase (MetC), an enzyme that catalyzes the last step in the biosynthesis of methionine, which is an essential amino acid in bacteria and plants. Following overexpression in Escherichia coli, the M. tuberculosis MetC enzyme was purified and crystallized using the hanging-drop vapor-diffusion method. Native diffraction data were collected from crystals belonging to space group P2(1) and were processed to a resolution of 2.1 Å.