P-31 solid-state NMR measurements used to detect interactions between NADPH and water and to determine the ionisation state of NADPH in a protein-ligand complex subjected to low-level hydration
Φόρτωση...
Ημερομηνία
Συγγραφείς
Gerothanassis, I. P.
Barrie, P. J.
Birdsall, B.
Feeney, J.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Wiley-Blackwell
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
European Journal of Biochemistry
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
P-31-NMR spectra of NADPH and NADPH bound to Lactobacillus casei dihydrofolate reductase have been recorded using the techniques of cross-polarization, magic-angle spinning and high-power proton-decoupling on both lyophilized and hydrated samples. Previous studies on the lyophilized complex of L. casei dihydrofolate reductase with NADPH and methotrexate, measuring the isotropic shifts and principal components of the chemical shift tensors, have shown that the 2'-phosphate group of bound NADPH exists as a mixture of the dianionic and monoanionic states [Gerothanassis, I. P., Barrie, P. J., Birdsall, B. & Feeney, J. (1994) Eur. J. Biochem. 226, 211-218]. In the present study on hydrated samples, the characterization of the isotropic shift and chemical shift tensors of the 2'-phosphate signal indicates that the 2'-phosphate is almost exclusively in the dianionic state. This is in agreement with earlier P-31-NMR studies in solution [Feeney, J., Birdsall, B., Roberts, G. C. K. & Burgen, A. S. V. (1975) Nature 257, 564-566]. In experiments examining progressively hydrated (6%, 12%, 15%, by mass) samples, the observed signals become increasingly narrower probably because the microenvironments of the P-31 nuclei become more homogeneous upon sample hydration. Chemical exchange between mobile water molecules and bound protons close to individual sites on NADPH has been indirectly monitored on a hydrated sample (15% water, by mass) using a pulse sequence proposed by Harbison and coworkers [Harbison, G. S., Roberts, J. E., Herzfeld, J. & Griffin, R. G. (1988) J. Am. Chem. Sec. 110, 7221-7223]. In this experiment, the two diphosphate signals are totally suppressed while the 2'-phosphate phosphorus signal remains: this indicates a significant polarization of the 2'-phosphate nuclei from protons in exchange with those of mobile water molecules.
Περιγραφή
Λέξεις-κλειδιά
p-31 solid-state nmri dihydrofolate reductase, nadph, magnetization transfer, hydration, casei dihydrofolate-reductase, nuclear magnetic-resonance, lactobacillus-casei, escherichia-coli, c-13-nmr spectroscopy, crystal-structures, magic angle, binding, methotrexate, conformation
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://A1996TQ25600034
http://onlinelibrary.wiley.com/store/10.1111/j.1432-1033.1996.00262.x/asset/j.1432-1033.1996.00262.x.pdf?v=1&t=hmn3nk3f&s=6b190f33f25046fccbcaef40d2de77445d4c4b8d
http://onlinelibrary.wiley.com/store/10.1111/j.1432-1033.1996.00262.x/asset/j.1432-1033.1996.00262.x.pdf?v=1&t=hmn3nk3f&s=6b190f33f25046fccbcaef40d2de77445d4c4b8d
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας