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NMR Facility Policy

Access to and Utilization of NMR Instruments in the Biomolecular NMR Facility

The biomolecular NMR instrumentation is available to all Vanderbilt University faculty, staff, and students who completed training and are active members of the users group. Training for new users is offered three times a year by the facility staff. All prospective users must either (1) successfully complete an appropriate training course or (2) demonstrate equivalent knowledge with regard to the operation of the NMR spectrometers. Users are also expected to participate in Users Group meetings, which are held twice per month.  Use of the NMR instrumentation of the facility is billed to the user’s P.I., and a cost center needs to be provided for each user.

Utilize Priorities

The Facility houses instrumentation essential for Biomolecular NMR research and was developed through funding of the Center for Structural Biology. Consequently, priority is given to Vanderbilt University faculty, staff, and students who are pursuing research in biomolecular NMR.  Broadly defined, biomolecular NMR experiments are performed on biological macromolecules, or complexes of biological macromolecules, including but not necessarily limited to, proteins, peptides, nucleic acids, oligonucleotides, oligosaccharides, and lipids, and are usually conducted in aqueous buffer. NMR data collection on other types of molecules, or in solvents other than aqueous buffer, is possible, but requires several adjustments of the controlling parameters. Prospective users with experiments not falling within the general regime of biomolecular NMR should inquire with Dr. Michael Stone, Chair of the User Committee.

Every effort is made to accommodate the access needs of all Vanderbilt University users in a timely manner. Biomolecular NMR experiments are time-intensive. The amount of sample is often limited, requiring substantial signal averaging to achieve reasonable signal-to-noise ratios, even with high magnetic fields or cryogenic probes. The complexity of the NMR spectra for large molecules generally mandates multi-dimensional data acquisition, also a time-intensive process. In many instances, samples are unstable, necessitating data collection before sample decomposition occurs.  In other instances, users must follow the time course of a biochemical process, necessitating multiple complex measurements as a function of time. Finally, because this is complex instrumentation, individual spectrometers in the facility may require unexpected maintenance and repair. Consequently, all users of the biomolecular NMR facility must be cognizant of the fact that there may often be a substantial wait for access to the instrumentation. Indeed, “walk-up” use of the instrumentation is not possible. When the NMR instrumentation is subject to high demand, the Biomolecular NMR Facility staff may find it necessary to prioritize individual experiments and to re-schedule the experiments of individual users, so as to utilize the NMR instrumentation as efficiently and as effectively as is possible. In appropriate instances, individual users may be requested to shift their experiments to other instruments, e.g., to a lower magnetic field strength instrument, or a non-cryoprobe-equipped instrument, if in the judgment of the facility staff, the experiments in question could be successfully conducted on another instrument. Oversight of instrument utilization and potential conflict resolution are handled by a faculty user committee.

Requesting Instrument Time

All authorized users who have completed appropriate training courses or who demonstrate comparable experience, are eligible to request NMR time, via a web-based sign-up system. The sign-up system allows users to request time on specific NMR instruments and requires a listing of the experiments to be performed. This documentation is used by the staff to facilitate scheduling, since the instruments are run on a 24 hour/day, 7 days/week basis. The facility staff will do everything in their power to schedule users in a way that minimizes their need to be at the console late at night and weekends, and to accommodate any special needs, e.g. the collection of kinetic data. However, during busy periods, users must anticipate the need to set up experiments at any time, day or night, weekdays or weekends. Plans for multiple day requests must be especially clearly detailed. The staff recognizes the need to balance instrument time distribution between well-justified long and short term experiments in order to accommodate a range of user time needs. It is each user’s responsibility to check the website and determine when they have been assigned time on a given machine. The website is the final word as to which user is assigned to which machine at a specific time.

If an instrument is not scheduled, the request queue defines the order of which persons can use the instrument. For this reason a request has always to be submitted before any user starts working on a spectrometer. This typically happens only if instrument usage is low and the facility manager has not yet updated the schedule that day.

When changes are made in already-awarded time,users will be informed of the change. The website data is used to monitor NMR usage by individual user groups. Once time is assigned, individual users are responsible for their experiments running during the assigned period. If a user cannot use his/her assigned instrument time, it is their responsibility to notify the facility staff in a timely manner, so that another user can use the time instead.  Such changes must be relayed to and approved by facility staff. Scheduled instrument time will be charged if cancelled less than 2 days before the start of scheduled time, unless another user can be found. Users who are consistently unprepared to use their assigned access times may lose access privileges.

Collecting Data

No adjustments to the NMR hardware are permitted without clearance from facility staff. Users who anticipate a need to adjust spectrometer hardware should consult in advance with facility staff and arrange to schedule experiments during time periods when staff will be available to assist as is necessary.  Where a change in hardware has been carried out, it is essential to restore the instrument to its original configuration following use. The maximum allowed temperature on any instrument is 60 deg. C. When variable temperature work has been undertaken, the temperature should be reset to 25 degrees upon completion.

The use of proper pulse sequences and parameters is essential because errors can lead to costly damage of the NMR probe. A standard library of fully verified experiments with appropriate standard parameters is available for all users. These pulse programs include the standard Bruker pulse sequences or modified sequences with an extension “.mv”. If an experiment is needed that is not in the library, facility staff will assist in developing the pulse sequence and testing. In such cases, it is imperative to provide the staff with as much advance notice as possible.  Instrument time for development will be billed at the usual rate. The facility staff is available to help users develop the knowledge needed to create new pulse programs and set parameters. Once a user achieves a reasonable level of proficiency as judged by the facility staff, the staff will provide certification for their creation and use of specific non-“.mv” standard sequences. Users should never attempt to use pulse sequences obtained from external sources without first having them checked by facility staff. Downloading of pulse sequences and parameters from an external website does not mean these will work properly in the Vanderbilt University facility. If users observe error messages or warning signals during operation of an instrument, they should report these to facility staff immediately, as such messages may indicate serious problems that must be corrected.

Many biomolecular NMR experiments involve collecting data over a period of days. When running long experiments, users must check daily in person at the console that the machine is running properly.

When time is scheduled based on days, it is to be understood that an NMR day begins and ends at 10 AM, which is the time at which the next scheduled user should expect to begin his/her experiments. It is critical that your experiment not run beyond the time specifically assigned to you. Moreover, users are expected to remove their own samples from the machine and transfer NMR data prior to the start of the next users time.

The Users Committee requests that each user and their P.I. carefully consider that in some cases, the scientific contributions made by the staff to a particular project are sufficient to merit being listed as a co-author of any resulting papers. Moreover, long term involvement in one or more projects may justify fractional salary support for the staff member from the grant supporting the research program.

Data Storage

All data needs to be copied to the user’s local computer system or the CSB disk space and archived immediately following completion of acquisition. All .ser and .fid files will be deleted 21 days after the data is created. All files containing processed spectra are deleted every Sunday morning at 4 AM.

Users Group Meetings

Users are required to attend Users Group meetings which will be held twice a month. The purpose of these meetings is to enhance communication and cooperation within the Vanderbilt NMR community and to provide informal education in NMR spectroscopy. Users are expected to attend these 1 hour meetings. Failure by a user to participate in these meetings without a compelling excuse may result in loss of facility access privileges.

Other Considerations

The Vanderbilt University Biomolecular Center is one of the largest dedicated to Biomolecular NMR facilities in the country. The policies and procedures regarding access to this multi-user facility were designed, and are evaluated periodically, to ensure that it operates at the highest possible efficiency for the entire user community. All users view their continuing access to this facility as a unique privilege. Please do not abuse this privilege!

Please address your concerns and any suggested modifications to the Chair of the User Committee, Michael Stone.