Biomedical subjects

T E Malliavin

Publications and source records attributed to T E Malliavin.

3 recordsLinked to original sources

PubMed1999

Quantitative measurement of longitudinal and transverse cross-relaxation rates: an application to the analysis of the internal dynamics of ranalexin in water and trifluoroethanol.

We describe a quantitative processing method which gives access to the longitudinal and transverse cross-relaxation rates from off-resonance ROESY intensities. This method takes advantage of the dependence of the off-resonance ROESY experiments at any mixing time and any spin-lock angle θ on two relaxation matrices, the longitudinal and the transverse ones. This allows one to take into account multistep magnetization transfers even if the measurements are performed only at one or two mixing times. The ratio of the longitudinal to transverse cross-relaxation rates can then be used as a local indicator of the internal dynamics, without assuming a structure or a model of motion. After validation of this processing method by numerical simulations, it is applied to the analysis of the dynamics of the peptide ranalexin dissolved in pure water and in water/TFE.

Anti-Infective Agents↗

PubMed1998

An NMR assignment module implemented in the Gifa NMR processing program.

MOTIVATION: Peptide and protein structures are determined daily using NMR spectroscopy. Assignment of the NMR spectra is an important step within the procedure and is usually the limiting one. Computer-aided assignment tools should be user friendly with open architecture to communicate with other programs involved in the structure determination. RESULTS: Here we present an interactive NMR assignment module which provides numerous graphic tools for the user. The module is composed of a database management system-handling peaks, spins and spin-systems. The assignment information is maintained as a set of interrelated associative arrays, which serve as generic high-level data structures. The module is developed in the macro language embedded in the Gifa NMR processing program (Pons et al. , J. Biomol. NMR, 8 , 445-452, 1996). This provides the user with a consistent interface, a set of sophisticated tools, and an easily extendible and customizable environment. AVAILABILITY: The program is available on request from the authors. The Gifa package can be accessed at: ((http://www.cbs. univ-montp1.fr/GIFA)) CONTACT: Marc-Andre.Delsuc@cbs.univ-montp1.fr

Database Management Systems↗

PubMedDate not supplied

Accurate estimation of inter-atomic distances in large proteins by NMR.

Recently a method was proposed which permits the extraction of the exact interatomic distance information from the measurement of the evolution of a single cross-peak relative to the mixing time in a NOESY experiment. This is performed through a careful multi-exponential analysis allowing the extraction of the relaxation parameter, and, consequently, the inter-proton distance. We investigate in the present paper whether this technique, already evaluated theoretically, can be used in a real experimental case. We have recorded and analyzed a set of 56 NOESY experiments on a lysozyme sample. Some 81 nOe build-up curves obtained from these data were analyzed in terms of distance. It is shown that the correlation between the measured distances and the reference distances obtained from crystallographic studies, is quite good. An accuracy of the order of 10% is obtained.

Magnetic Resonance Spectroscopy↗