The BioMagResBank (BMRB: www.bmrb.wisc.edu) is a repository for experimental and derived data gathered from nuclear magnetic resonance (NMR) spectroscopic studies of biological molecules. BMRB is a partner in the Worldwide Protein Data Bank (wwPDB). The BMRB archive consists of four main data depositories: (i) quantitative NMR spectral parameters for proteins, peptides, nucleic acids, carbohydrates and ligands or cofactors (assigned chemical shifts, coupling constants and peak lists) and derived data (relaxation parameters, residual dipolar couplings, hydrogen exchange rates, pKa values, etc.), (ii) databases for NMR restraints processed from original author depositions available from the Protein Data Bank, (iii) time-domain (raw) spectral data from NMR experiments used to assign spectral resonances and determine the structures of biological macromolecules and (iv) a database of one- and two-dimensional 1H and 13C one- and two-dimensional NMR spectra for over 250 metabolites. The BMRB website provides free access to all of these data. BMRB has tools for querying the archive and retrieving information and an ftp site (ftp.bmrb.wisc.edu) where data in the archive can be downloaded in bulk. Two BMRB mirror sites exist: one at the PDBj, Protein Research Institute, Osaka University, Osaka, Japan (bmrb.protein.osaka-u.ac.jp) and the other at CERM, University of Florence, Florence, Italy (bmrb.postgenomicnmr.net/). The site at Osaka also accepts and processes data depositions.

The interaction of mono-, di-, and trivalent metal ions with bilayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was investigated with deuterium and phosphorus magnetic resonance. With selectively deuterated lipids the measurements of the residual deuterium quadrupole splitting provided a sensitive handle to monitor directly the binding of ions, including the weak binding of Na+ or (CH3)4N+. For the a segment of the choline group (-N-CH2CD20-) changes in the quadrupole splitting of up to 9 kHz were observed. All measurements were made with nonsonicated DPPC dispersions. The ion concentrations were varied between 5 mM and 2 M, an almost 50-fold larger concentration range than accessible with nuclear magnetic resonance shift reagents. From a systematic comparison of various ions the following conclusions could be derived. (1) Addition of metal ions led to a structural change at the level of the polar groups. The glycerol backbone or the beginning of the fatty acyl chains was not affected. (2) The strength of interaction increased with the charge of the metal ion in the order Na+ < Ca2+ C La3+. However, distinct differences were also noted between ions of the same charge. Furthermore, the strongly hydrophobic tetraphenylammonium ion Phosphatidylcholine is one of the predominant phospholipids in membranes, and a large fraction of most membrane surfaces is occupied by phosphocholine groups. The interactions of metal ions with the uncharged phosphatidylcholine bilayer can be expected to be relatively weak compared to those with negatively charged lipids such as phosphatidylglycerol or phosphatidylserine. Nevertheless, even small changes in the head-group orientation and flexibility could significantly alter the electrical properties of the membrane surface, producing, in turn, changes in the physiological or biochemical characteristics of the membrane. Thus, the problem of metal ion binding to phosphatidylcholine bilayers has attracted much attention, and a variety of methods have been employed [for a review, see Hauser & Phillips (1 979)]. Deuterium magnetic induced almost the same change as La3+. (3) The variation of the quadrupole splittings with ion concentration exhibited a plateau value at high concentrations of La3+. The titration curves of DPPC with Ca2+ and La3+ could be described in terms of a Langmuir adsorption isotherm with an interaction potential. Apparent binding constants of KLacI, N 120 M-' and KQCl2 N 19 M-' were derived. (4) The addition of NaCl considerably enhanced the binding of Ca2+ and La3+, apparently without affecting the plateau value of the quadrupole splitting. (5) The ion-induced conformational changes were qualitatively similar for all ions investigated. The various binding data could be summarized by plotting the quadrupole splittings of the a segment (-OCD2CH2N-) vs. those of the P position (-OCH2CD2N-). This plot yielded a straight line comprising all ions and concentrations investigated except Eu3+.The quadrupole splittings of DPPC observed in the presence of chloroform or...

The subunit of bacterial and chloroplast FoF1-ATP synthases modulates their ATP hydrolysis activity. Here, we report the crystal structure of the ATP-bound subunit from a thermophilic Bacillus PS3 at 1.9-Å resolution. The C-terminal two ␣-helices were folded into a hairpin, sitting on the ␤ sandwich structure, as reported for Escherichia coli. A previously undescribed ATP binding motif, I(L)DXXRA, recognizes ATP together with three arginine and one glutamate residues. The E. coli subunit binds ATP in a similar manner, as judged on NMR. We also determined solution structures of the C-terminal domain of the PS3 subunit and relaxation parameters of the whole molecule by NMR. The two helices fold into a hairpin in the presence of ATP but extend in the absence of ATP. The latter structure has more helical regions and is much more flexible than the former. These results suggest that the Cterminal domain can undergo an arm-like motion in response to an ATP concentration change and thereby contribute to regulation of F oF1-ATP synthase.ATP hydrolysis ͉ ATP-binding motif ͉ ATPase regulation ͉ ATP synthase ͉ F1 rotation