Graheme J. B. Williams

The Protein Data Bank: a computer-based archival file for macromolecular structures.

The Protein Data Bank is a computer-based archival file for macromolecular structures. The Bank stores in a uniform format atomic co-ordinates and partial bond connectivities, as derived from crystallographic studies. Text included in each data entry gives pertinent information for the structure at hand (e.g. species from which the molecule has been obtained, resolution of diffraction data, literature citations and specifications of secondary structure). In addition to atomic co-ordinates and connectivities, the Protein Data Bank stores structure factors and phases, although these latter data are not placed in any uniform format. Input of data to the Bank and general maintenance functions are carried out at Brookhaven National Laboratory. All data stored in the Bank are available on magnetic tape for public distribution, from Brookhaven (to laboratories in the Americas), Tokyo (Japan), and Cambridge (Europe and worldwide). A master file is maintained at Brookhaven and duplicate copies are stored in Cambridge and Tokyo. In the future, it is hoped to expand the scope of the Protein Data Bank to make available co-ordinates for standard structural types (e.g. alpha-helix, RNA double-stranded helix) and representative computer programs of utility in the study and interpretation of macromolecular structures.

Bridged Ferrocenes: IV. The crystal and molecular structure of 1,1′,2,2′,3,3′,4,5,4′,5′-pentakis(trimethylene)ferrocene

The title compound (molecular formula C 25 H 30 Fe) forms prismatic crystals from hexane which belong to the monoclinic space group P 2 1 / n with lattice constants a 9.486(2), b 12.134(2), c 16.024(2)A, β 93.12(1)°, and Z = 4. The structure was solved by the heavy atom method and refined by full-matrix least squares against 3839 F 2 terms to yield R = 0.08 and R w = 0.12. The Fe to cyclopentadienyl ring-carbon distances range from 1.985(3) to 2.042(4)A. The two cyclopentadienyl rings are eclipsed, they are slightly non-planar, and the angle between their least-squares planes is 12.5°.

The Crystal Structure of PrOHSO4

The phase equilibria and structural relationships of the anion substitution phases of the lanthanide hydroxides are both interesting and complex. The consequences of anion substitution have been most thoroughly investigated for monovalent anion systems of the type Ln(OH) 3−xXx (X=Xl−, Br−, I−, NO−3). Equilibria, structures and structural correlations of these systems are described and reviewed in recent reports. (1–3)