Structure Determination

The tertiary structure of a macromolecule is its three-dimensional structure defined by the atomic coordinates. Up to present, the common drug targets are proteins and nucleic acids. Proteins and nucleic acids need to fold into complex three-dimensional structures to produce molecular functions. Structure determination is a procedure to obtain the three-dimensional structures using various analytical techniques such as X-ray crystallography, cryo-electron microscopy, nuclear magnetic resonance (NMR) spectroscopy and small-angle scattering. When a target is identified, the explanation of molecular geometry (i.e. the spatial position of atoms in molecules and the chemical bonds that keep atoms together) and the electronic form is essential. Structure determination has been widely used in a group of targets, not only extremely complex ones, but also very simple molecules.

Figure 1. Overall Structure of MmpL3 from M. smegmatis. (Zhang, B., et al., 2019)

Creative Biolabs offers high-quality structure determination services to get exact structural information for target validation of drug discovery process thus to deal with data reproducibility crisis which is a big obstacle for drug research and development and may lead to failure and high risk of investment.

Creative Biolabs offers structure determination services based on various approaches, including but not limited to the following:

X-Ray Crystallography

X-ray crystallography is a useful technique for determining the atomic and molecular structure of a crystal. X-ray crystallography uses the scattering effect of electrons on X-ray to obtain the distribution of electron density in crystals and a variety of other information such as atomic position, chemical bond and crystallographic disorder. This technique has become one of the most favorite tools for structure determination.

Nuclear Magnetic Resonance (NMR) Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy is a spectroscopic technique based on the phenomena of nuclear magnetic resonance to observe local magnetic fields around atomic nuclei. NMR spectroscopy can provide specified information about the dynamics, reaction state, structure, and chemical state of molecules. This technique has been used to analyze the intact structural and conformational of complex molecules and the quantitative analysis of the complex mixtures.

Cryo-Electron Microscopy

Cryo-electron microscopy (cryo-EM) is a transmission electron microscopy technique that is applied on samples cooled to cryogenic temperatures and is gradually turning into a favorite tool for researching the formation of cells, viruses, and protein fittings at molecular resolution. This technique without the need for crystallization has attracted wide attention and became an alternative to X-ray crystallography or NMR spectroscopy for macromolecular structure determination.

Small-Angle Scattering

Small angle scattering (SAS) is a scattering technique that can give information about the size, shape and direction of the structure in the sample. SAS can refer to small-angle X-ray scattering (SAXS) or small-angle neutron scattering (SANS). SAXS is a small angle scattering technique to quantify the nanoscale density difference in the sample. SANS is another small angle scattering technique that uses elastic neutron scattering at small scattering angles to investigate the structure of various substances.

Creative Biolabs has a dedicated assay development team that will work closely with you to design customized assays. Our service will meet your specific needs fast at extremely competitive prices. If you need more information, please feel free to contact us at anytime. We look forward to working with you to help your drug research and development project succeed.

Reference

1. Zhang, B., et al., 2019. Crystal structures of membrane transporter MmpL3, an anti-TB drug target. Cell, 176(3), pp. 636-648.