Analytical Ultracentrifugation Facility
Analytical ultracentrifugation (AUC) methods are enjoying a resurgence of interest in recent years for reason of new sample detection methods and much improved data handling and structural analyses. The availability of two AUC instruments in the lab makes possible simultaneous velocity and equilibrium experiments so that protein associative behaviour in solution can be explored in detail.

The two AUC instruments were funded by several external equipment grants to Prof Steve Perkins as PI. Other funding has come from UCL via SRIF, a CIF bid made jointly with Biochemical Engineering, and a further CIF bid. Our track record with setting up the AUC enables us to claim that we are the most successful AUC laboratory in the London area. We are always interested in new AUC collaborations with colleagues.

It should be noted that we also possess Biacore surface plasmon resonance (SPR) and dual polarisation interferometry (DPI) equipment which makes complementary measurements on sensor surfaces compared to those in solution from AUC (see “Biacore”).

Contacts

Please email Jayesh Gor in the first instance: Academic (who should often be the first point of call, to advise on feasibility and experimental plan) – Prof Steve Perkins (Structural and Molecular Biology): 020 7679 7048 (via Hearing Assistant) s.perkins@ucl.ac.uk Technician (day-to-day and practical issues) – Jayesh Gor: 020 7679 2989 j.gor@ucl.ac.uk


Location
Room SB16 in the Darwin Subbasement - two Beckman AUC instruments
Second floor in the Darwin – Anton-Paar densitometer, server for AUC data storage, multi-user PCs for data analysis.

List of Equipment
One Beckman XL-I analytical ultracentrifuge (purchased 1998) equipped with absorbance, interference and fluorescent optics. The fluorescent optics permit measurements down to pM concentrations. Eight-hole and four-hole rotors. Aluminium and carbon six-sector and two-sector cells.

One Beckman XL-I analytical ultracentrifuge (purchased 2007) equipped with absorbance and  interference optics. Eight-hole and four-hole rotors. Aluminium and carbon six-sector and two-sector cells.

Techniques and capabilities
There are two types of experiments:
(1) In sedimentation equilibrium experiments at low rotor speeds, diffusion opposes the process of sedimentation. When the two opposing forces reach equilibrium, the sample distribution is exponential in appearance. Molecular weights are obtained and equilibria can be studied to yield dissociation constants.
(2) In sedimentation velocity experiments, if the sample is subjected to a high speed centrifugal field, the rapid sedimentation of protein towards the bottom of the cell occurs. The sedimentation coefficient provides structural data, and sample polydispersity is readily analysed using size distribution c(s) plots. We can study a broad range of complexes by this approach. In particular, the sedimentation coefficients can be directly compared with predicted values calculated from crystallography and/or NMR structures.

Costs/Charges

Negotiable. Usually we charge £100 per run (+ VAT if required) for maintenance to those at UCLwith grant support. A typical in-depth project carried out to completion costs about £500-£1000. Please contact us if you need costs for a grant application.


Training
We will run the samples for you. Data processing is the users’ responsibility and we provide users with either access to multiuser PC’s or give them their data and the necessary software. We have written protocols based on our setup that can be used by undergraduates, graduate students and upwards.

Publications
This link provides a short description of our recent projects that illustrates the above:
http://www.smb.ucl.ac.uk/bsm/structure/Ultracentrifugation.htm
This has a series of photographs and images that reflects the work in the AUC laboratory.

We have described the AUC facility in the ISMB Newsletter (issues 1 and 2) – see our website

This link provides a list of our publications based on the analytical ultracentrifuge as well as other technologies including X-ray and neutron scattering and constrained modelling. Our own interests reside in the study of the weak and strong interactions that comprise the immune response.
http://www.smb.ucl.ac.uk/bsm/structure/Publications


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Page last modified on 05 jun 13 15:19