Equipment

The School of Biological Sciences houses  a variety of equipment for studying the structure, dynamics and interactions of biological molecules. If you want to use these instruments please contact Dr Richard Kingston (rl.kingston@auckland.ac.nz), who can explain the access arrangements.


Laser Light Scattering


Dynamic Light Scattering allows us to measure the speed at which molecules move through solution - which is dependent on their size and shape. We have a Wyatt  Dynapro Titan dynamic light scattering instrument.


Static Light Scattering allows us to estimate the mass of proteins and protein assemblies.  We have a Polymer Standards Service SLD7000 Multi-Angle Laser Light Scattering detector linked to a Dionex HPLC. This enables Size Exclusion Chromatography coupled with Multi-angle Laser Light Scatterring (SEC-MALLS).


Spectroscopy


Ultraviolet and visible  absorbance spectroscopy

The absorption of ultraviolet and visible light by molecules has numerous applications. These include simple concentration measurements, the study of enzymatic reactions, and the study of molecular conformation. We have a Cary 4000 UV / visible spectrometer with a thermostatted multi-cell holder.


Circular Dichroism and Fluorescence Spectroscopy 

Circular dichroism (CD) spectroscopy is a very sensitive probe of molecular conformation. It is frequently used to study protein stability as a function of temperature or solution composition, and to follow conformational changes associated with binding. We have Applied Photophysics PiStar and Chirascan Spectrometers. The Chirascan is used exlusively for CD spectroscopy. The Pistar is also capable of making fluoresence measurements and has a stopped flow accessory, enabling the study of very rapid processes.


Temperature Scanning Fluorimetry.

Real Time PCR machines have a lot of applications in biology. We have one, but we don't use it for PCR. We use it for the qualitative study of protein stability. The temperature at which a protein unfolds is assessed by the increase in fluorescence of a hydrophobic dye, which binds to the exposed core of the protein as it unravels. A Bio-Rad MyIQ Real Time PCR system, is dedicated to these experiments.


Calorimetry


Isothermal Titration Calorimetry is a basic quantitative technique for studying molecular interactions, in which the tiny amount of heat released or absorbed during binding is accurately measured. From this raw data, a very complete description of binding can be achieved. The technique can also be used to study enzymatic reactions. A Microcal VP-ITC isothermal titration calorimeter was installed in 2007. 


Differential Scanning Calorimetry is a basic quantitative technique for studying molecular stability, in which the heat required to raise the temperature of a molecular solution is measured. Applied to proteins, this can provide a comprehensive energetic description of the protein folding and unfolding process. A TA Instruments Nano DSC was installed in 2015.


Measurement of solution properties


Measurement of the refractive index of solutions is required for light scattering studies, and is also often used to measure solution composition in biochemistry and biophysics. We have a Schmidt and Haensch multiple wavelength refractometer.


Measurement of solution viscosity is required for correct interpretation of hydrodynamic techniques, involving molecular diffusion. It can also tell us something about molecular conformation, as the impacts of a molecule on solution viscosity are very sensitive to shape. We have a Rheosense microfluidic viscometer (m-VROC), with accurate temperature control (4-100 °C)


Interpretation of data from hydrodynamic techniques sometimes requires the measurement of solution density. We have a Rudolph DDM 2910 Digital Density Meter to enable this.


High Resolution Molecular Imaging


X-ray diffraction

X-ray crystallography is the highest resolution direct imaging technique currently available. X-rays can be used to visualize structures at the atomic and molecular level - covering sizes from 0.1 - 100 nm. Installed in 2006, was a Rigaku MicroMax-007 HF rotating anode generator, 2 mar research desktop beamline stations, Osmic mirror optics, and an Oxford Cobra cryo-cooling system.


Electron Microscopy

The electron microscope can be used to visualize molecules and molecular assemblies that are too large or too irregular to be studied by X-ray diffraction. Electron microscopy is also uniquely suited for the study of integral membrane proteins. Housed in the basement is a FEI Tecnai FEG20 electron microscope, equipped with a high- tilt Cryo-stage and a Gatan Energy Filter.  We have an automated vitrification system for cryo-em sample preparation  (FEI Vitrobot). This equipment is managed as part of the University’s Imaging Centre.


Other Equipment


Nuclear Magnetic Resonance spectroscopy


Nuclear Magnetic Resonance (NMR) spectroscopy, based on the absorbance of radio frequency radiation, is one of the most powerful spectroscopic techniques in biology. It provides information on molecular structure and dynamics. Not housed within SBS, but nearby in the chemistry department, is a Bruker 600 MHz NMR spectrometer equipped with a triple resonance cryoprobe, suitable for solution NMR spectroscopy of biological samples.  This equipment is part of the University’s NMR centre.