摘要:

AbstractSmall‐angle x‐ray scattering studies have been carried out on the enzyme yeast inorganic pyrophosphatase (PPase), and its overall conformational changes on interaction with divalent metal ions (Mg2+and Mn2+) and with phosphoryl ligands [inorganic phosphate (Pi) and hydroxymethane bisphosphonate (PCHOHP), a nonhydrolyzable inorganic pyrophosphate analog] were assessed. The enzyme undergoes an apparent reduction in size on simultaneous addition of Mg2+and high Piconcentration, although neithough neither Mg2+nor Piadded separately induced any measurable conformational changes. By contrast, simultaneous addition of Mn2+and Pito PPase does not result in an observable conformational change. However, the overall structure of the enzyme appears to enlarge in the simultaneous presence of Mn2+ions and PCHOHP. The significance of the structural changes seen in PPase under various conditions is discus

ISSN:0006-3525    

DOI:10.1002/bip.360230112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe method of Ermak and McCammon [Ermak, D. L.&McCammon, J. A. (1978)J. Chem. Phys.69, 1352–1360] is used to simulate the Brownian dynamics of a system of identical, interacting beads. In the present study, we use the method to obtain transport coefficients for a variety of rigid and flexible structures modeled as arrays of spherical subunits. Constraints are enforced using the SHAKE algorithm or a modification, SHAKE‐HI, that is described for the first time. In SHAKE‐HI, hydrodynamic interactions between subunits are taken into account when the constraints are enforced. Use of SHAKE‐HI yields transport coefficients that are in perfect agreement with those obtained by other methods. The primary advantage of the present method is its generality. We also propose that multistep Brownian dynamics may be important in simulating actual experiments (such as fluorescence depolarization) on well‐defined model systems that possess an arbitrary degree of internal fl

ISSN:0006-3525    

DOI:10.1002/bip.360230113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0006-3525    

DOI:10.1002/bip.360230101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY