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H H Paradies

Publications and source records attributed to H H Paradies.

At least 19 recordsLinked to original sources
PubMed1979

Structure of cross-linked rabbit muscle phosphofructokinase in solution.

Cross-linked rabbit muscle phosphofructokinase in the active tetrameric and octameric state was studied in solution by hydrodynamic methods and small angle x-ray scattering techniques. The translational diffusion coefficients were determined by means of inelastic light scattering and were found to be 3.60 (+/- 0.02) x 10(-7) cm2 . s-1 for the tetramer and 2.54 (+/- 0.15) x 10(-7) cm2 . s-1 for the octamer. From small angle x-ray scattering measurements the radius of gyration, the specific inner surface area, and the volume were determined for both enzyme forms, revealing that the octameric cross-linked form is approximately spherical, with a diameter of 120.0 A, whereas the tetrameric form is asymmetric having an axial ratio of 2. By comparison of the scattering curves with triaxial geometric bodies which are equivalent in scattering, the tetrameric enzyme is described as a rectangular prism, with overall dimensions of A = 131.0 A, B = 131.0 A, and C = 65.0 A, and the octameric form as that of a cube with A = B = C = 120.0 A. The shape of the protomer, having a radius of gyration of 24.8 A, in the tetramer and octamer is similar to that for the native tetramer at pH 10 in the presence of 5 mM fructose 6-phosphate or 15 mM fructose 1,6-bis-phosphate. From the different shapes of the scattering curves of the native phosphofructokinase at pH 7.5 in the presence of 15 mM ATP and of the cross-linked tetramer or octamer, it can be inferred that the shapes of the protomers are different: in the presence of ATP the protomers are elongated, having an axial ratio of 1.8 to 2.0; the cross-linked state reveals a spherical protomer of radius 33.0 A, similar to that of the native enzyme at pH 7.5 in the presence of fructose 6-phosphate or fructose 1,6-bisphosphate.

Animals↗
PubMed1979

Size and molecular parameters of adenosine triphosphatase from Escherichia coli.

The Mg2+- and Ca2+-stimulated ATPase (bacterial coupling factor) has been investigated in solution with different independent techniques. The molecular weight of the five-subunit enzyme was found to be 345,000 +/- 5,000 by means of light scattering, 350,000 by sedimentation equilibrium experiments, and 358,000 by means of small-angle x-ray scattering. The radius of gyration was found to be 41.9 A, the volume 7.39 x 10(5) A3, and the surface to volume ratio 5.5 x 10(-2) A-1 from small-angle x-ray scattering measurements of the enzyme in solution. The degree of hydration was found to be 0.62 ml of H2O/g of ATPase. The translational diffusion coefficient was determined to be 3.47 x 10(-7) cm2 s-1 by means of inelastic light scattering. The distribution of the scattered intensity near the origin appears to be bimodal, suggesting that the ATPase molecule is composed of spherical parts bound together by a flexible polypeptide chain. The largest dimension of the ATPase in solution is 120.0 A, determined from the pair distribution function.

Calcium-Transporting ATPases↗
PubMed1976

Geometry of the protein S4 from Escherichia coli ribosomes.

The shape of protein S4 from Escherichia coli ribosomes in solution was determined by hydrodynamic methods and low-angle X-ray scattering. The molecular weight of 24000 determined by low-angle X-ray scattering is within 3% of that found by sedimentation equilibrium analysis and 8% of that determined by amino acid sequence work. The radius of gyration of 3.36 nm, the radius of gyration of the cross section of 0.41 nm and the hydrodynamic studies revealed that protein S4 is not spherical, but rather has a markedly extended shape. Calculations of different conformations, e.g. random coil, based on the parameters evaluated from hydrodynamic methods, revealed a rod-like structure of S4 with a length of 14 nm and a diameter of 1 nm. This is supported by a model of an equivalent scattering particle of uniform density based on all parameters obtained in this study.

Bacterial Proteins↗